Class: PG::Connection

Inherits:
Object
  • Object
show all
Includes:
Constants
Defined in:
lib/pg/connection.rb,
ext/pg_connection.c

Overview

The PostgreSQL connection class. The interface for this class is based on libpq, the C application programmer’s interface to PostgreSQL. Some familiarity with libpq is recommended, but not necessary.

For example, to send query to the database on the localhost:

require 'pg'
conn = PG::Connection.open(:dbname => 'test')
res = conn.exec_params('SELECT $1 AS a, $2 AS b, $3 AS c', [1, 2, nil])
# Equivalent to:
#  res  = conn.exec('SELECT 1 AS a, 2 AS b, NULL AS c')

See the PG::Result class for information on working with the results of a query.

Many methods of this class have three variants kind of:

  1. #exec - the base method which is an alias to #async_exec . This is the method that should be used in general.

  2. #async_exec - the async aware version of the method, implemented by libpq’s async API.

  3. #sync_exec - the method version that is implemented by blocking function(s) of libpq.

Sync and async version of the method can be switched by Connection.async_api= , however it is not recommended to change the default.

Constant Summary

Constants included from Constants

PG::Constants::CONNECTION_AUTH_OK, PG::Constants::CONNECTION_AWAITING_RESPONSE, PG::Constants::CONNECTION_BAD, PG::Constants::CONNECTION_CHECK_STANDBY, PG::Constants::CONNECTION_CHECK_TARGET, PG::Constants::CONNECTION_CHECK_WRITABLE, PG::Constants::CONNECTION_CONSUME, PG::Constants::CONNECTION_GSS_STARTUP, PG::Constants::CONNECTION_MADE, PG::Constants::CONNECTION_NEEDED, PG::Constants::CONNECTION_OK, PG::Constants::CONNECTION_SETENV, PG::Constants::CONNECTION_SSL_STARTUP, PG::Constants::CONNECTION_STARTED, PG::Constants::DEF_PGPORT, PG::Constants::INVALID_OID, PG::Constants::INV_READ, PG::Constants::INV_WRITE, PG::Constants::InvalidOid, PG::Constants::PGRES_BAD_RESPONSE, PG::Constants::PGRES_COMMAND_OK, PG::Constants::PGRES_COPY_BOTH, PG::Constants::PGRES_COPY_IN, PG::Constants::PGRES_COPY_OUT, PG::Constants::PGRES_EMPTY_QUERY, PG::Constants::PGRES_FATAL_ERROR, PG::Constants::PGRES_NONFATAL_ERROR, PG::Constants::PGRES_PIPELINE_ABORTED, PG::Constants::PGRES_PIPELINE_SYNC, PG::Constants::PGRES_POLLING_FAILED, PG::Constants::PGRES_POLLING_OK, PG::Constants::PGRES_POLLING_READING, PG::Constants::PGRES_POLLING_WRITING, PG::Constants::PGRES_SINGLE_TUPLE, PG::Constants::PGRES_TUPLES_OK, PG::Constants::PG_DIAG_COLUMN_NAME, PG::Constants::PG_DIAG_CONSTRAINT_NAME, PG::Constants::PG_DIAG_CONTEXT, PG::Constants::PG_DIAG_DATATYPE_NAME, PG::Constants::PG_DIAG_INTERNAL_POSITION, PG::Constants::PG_DIAG_INTERNAL_QUERY, PG::Constants::PG_DIAG_MESSAGE_DETAIL, PG::Constants::PG_DIAG_MESSAGE_HINT, PG::Constants::PG_DIAG_MESSAGE_PRIMARY, PG::Constants::PG_DIAG_SCHEMA_NAME, PG::Constants::PG_DIAG_SEVERITY, PG::Constants::PG_DIAG_SEVERITY_NONLOCALIZED, PG::Constants::PG_DIAG_SOURCE_FILE, PG::Constants::PG_DIAG_SOURCE_FUNCTION, PG::Constants::PG_DIAG_SOURCE_LINE, PG::Constants::PG_DIAG_SQLSTATE, PG::Constants::PG_DIAG_STATEMENT_POSITION, PG::Constants::PG_DIAG_TABLE_NAME, PG::Constants::PQERRORS_DEFAULT, PG::Constants::PQERRORS_SQLSTATE, PG::Constants::PQERRORS_TERSE, PG::Constants::PQERRORS_VERBOSE, PG::Constants::PQPING_NO_ATTEMPT, PG::Constants::PQPING_NO_RESPONSE, PG::Constants::PQPING_OK, PG::Constants::PQPING_REJECT, PG::Constants::PQSHOW_CONTEXT_ALWAYS, PG::Constants::PQSHOW_CONTEXT_ERRORS, PG::Constants::PQSHOW_CONTEXT_NEVER, PG::Constants::PQTRANS_ACTIVE, PG::Constants::PQTRANS_IDLE, PG::Constants::PQTRANS_INERROR, PG::Constants::PQTRANS_INTRANS, PG::Constants::PQTRANS_UNKNOWN, PG::Constants::PQ_PIPELINE_ABORTED, PG::Constants::PQ_PIPELINE_OFF, PG::Constants::PQ_PIPELINE_ON, PG::Constants::SEEK_CUR, PG::Constants::SEEK_END, PG::Constants::SEEK_SET

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.async_api=(enable) ⇒ Object

Switch between sync and async libpq API.

PG::Connection.async_api = true

this is the default. It sets an alias from #exec to #async_exec, #reset to #async_reset and so on.

PG::Connection.async_api = false

sets an alias from #exec to #sync_exec, #reset to #sync_reset and so on.

pg-1.1.0+ defaults to libpq’s async API for query related blocking methods. pg-1.3.0+ defaults to libpq’s async API for all possibly blocking methods.

PLEASE NOTE: This method is not part of the public API and is for debug and development use only. Do not use this method in production code. Any issues with the default setting of async_api=true should be reported to the maintainers instead.



946
947
948
949
950
951
952
953
954
955
956
# File 'lib/pg/connection.rb', line 946

def async_api=(enable)
	self.async_send_api = enable
	REDIRECT_METHODS.each do |ali, (async, sync)|
		remove_method(ali) if method_defined?(ali)
		alias_method( ali, enable ? async : sync )
	end
	REDIRECT_CLASS_METHODS.each do |ali, (async, sync)|
		singleton_class.remove_method(ali) if method_defined?(ali)
		singleton_class.alias_method(ali, enable ? async : sync )
	end
end

.async_send_api=(enable) ⇒ Object



923
924
925
926
927
928
# File 'lib/pg/connection.rb', line 923

def async_send_api=(enable)
	REDIRECT_SEND_METHODS.each do |ali, (async, sync)|
		undef_method(ali) if method_defined?(ali)
		alias_method( ali, enable ? async : sync )
	end
end

.conndefaultsObject

call-seq:

PG::Connection.conndefaults() -> Array

Returns an array of hashes. Each hash has the keys:

:keyword

the name of the option

:envvar

the environment variable to fall back to

:compiled

the compiled in option as a secondary fallback

:val

the option’s current value, or nil if not known

:label

the label for the field

:dispchar

“” for normal, “D” for debug, and “*” for password

:dispsize

field size



377
378
379
380
381
382
383
384
385
386
387
388
# File 'ext/pg_connection.c', line 377

static VALUE
pgconn_s_conndefaults(VALUE self)
{
	PQconninfoOption *options = PQconndefaults();
	VALUE array = pgconn_make_conninfo_array( options );

	PQconninfoFree(options);

	UNUSED( self );

	return array;
}

.conndefaults_hashObject

Return the Postgres connection defaults structure as a Hash keyed by option keyword (as a Symbol).

See also #conndefaults



329
330
331
332
333
# File 'lib/pg/connection.rb', line 329

def self.conndefaults_hash
	return self.conndefaults.each_with_object({}) do |info, hash|
		hash[ info[:keyword].to_sym ] = info[:val]
	end
end

.connect_hash_to_string(hash) ⇒ Object

Convert Hash options to connection String

Values are properly quoted and escaped.



44
45
46
# File 'lib/pg/connection.rb', line 44

def self.connect_hash_to_string( hash )
	hash.map { |k,v| "#{k}=#{quote_connstr(v)}" }.join( ' ' )
end

.PG::Connection.connect_start(connection_hash) ⇒ Object .PG::Connection.connect_start(connection_string) ⇒ Object .PG::Connection.connect_start(host, port, options, tty, dbname, login, password) ⇒ Object

This is an asynchronous version of PG::Connection.new.

Use #connect_poll to poll the status of the connection.

NOTE: this does not set the connection’s client_encoding for you if Encoding.default_internal is set. To set it after the connection is established, call #internal_encoding=. You can also set it automatically by setting ENV['PGCLIENTENCODING'], or include the ‘options’ connection parameter.

See also the ‘sample’ directory of this gem and the corresponding libpq functions.



314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
# File 'ext/pg_connection.c', line 314

static VALUE
pgconn_s_connect_start( int argc, VALUE *argv, VALUE klass )
{
	VALUE rb_conn;
	VALUE conninfo;
	t_pg_connection *this;

	/*
	 * PG::Connection.connect_start must act as both alloc() and initialize()
	 * because it is not invoked by calling new().
	 */
	rb_conn  = pgconn_s_allocate( klass );
	this = pg_get_connection( rb_conn );
	conninfo = rb_funcall2( klass, rb_intern("parse_connect_args"), argc, argv );
	this->pgconn = gvl_PQconnectStart( StringValueCStr(conninfo) );

	if( this->pgconn == NULL )
		rb_raise(rb_ePGerror, "PQconnectStart() unable to allocate PGconn structure");

	if ( PQstatus(this->pgconn) == CONNECTION_BAD )
		pg_raise_conn_error( rb_eConnectionBad, rb_conn, "%s", PQerrorMessage(this->pgconn));

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_conn, pgconn_finish, rb_conn );
	}
	return rb_conn;
}

.conninfo_parse(conninfo) ⇒ Object

call-seq:

PG::Connection.conninfo_parse(conninfo_string) -> Array

Returns parsed connection options from the provided connection string as an array of hashes. Each hash has the same keys as PG::Connection.conndefaults() . The values from the conninfo_string are stored in the :val key.



400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
# File 'ext/pg_connection.c', line 400

static VALUE
pgconn_s_conninfo_parse(VALUE self, VALUE conninfo)
{
	VALUE array;
	char *errmsg = NULL;
	PQconninfoOption *options = PQconninfoParse(StringValueCStr(conninfo), &errmsg);
	if(errmsg){
		VALUE error = rb_str_new_cstr(errmsg);
		PQfreemem(errmsg);
		rb_raise(rb_ePGerror, "%"PRIsVALUE, error);
	}
	array = pgconn_make_conninfo_array( options );

	PQconninfoFree(options);

	UNUSED( self );

	return array;
}

.PG::Connection.encrypt_password(password, username) ⇒ String

This is an older, deprecated version of #encrypt_password. The difference is that this function always uses md5 as the encryption algorithm.

Returns:

  • (String)


456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
# File 'ext/pg_connection.c', line 456

static VALUE
pgconn_s_encrypt_password(VALUE self, VALUE password, VALUE username)
{
	char *encrypted = NULL;
	VALUE rval = Qnil;

	UNUSED( self );

	Check_Type(password, T_STRING);
	Check_Type(username, T_STRING);

	encrypted = PQencryptPassword(StringValueCStr(password), StringValueCStr(username));
	rval = rb_str_new2( encrypted );
	PQfreemem( encrypted );

	return rval;
}

.escape_bytea(string) ⇒ String

Escapes binary data for use within an SQL command with the type bytea.

Certain byte values must be escaped (but all byte values may be escaped) when used as part of a bytea literal in an SQL statement. In general, to escape a byte, it is converted into the three digit octal number equal to the octet value, and preceded by two backslashes. The single quote (‘) and backslash () characters have special alternative escape sequences. #escape_bytea performs this operation, escaping only the minimally required bytes.

Consider using exec_params, which avoids the need for passing values inside of SQL commands.

NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.

Returns:

  • (String)


1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
# File 'ext/pg_connection.c', line 1681

static VALUE
pgconn_s_escape_bytea(VALUE self, VALUE str)
{
	unsigned char *from, *to;
	size_t from_len, to_len;
	VALUE ret;

	Check_Type(str, T_STRING);
	from      = (unsigned char*)RSTRING_PTR(str);
	from_len  = RSTRING_LEN(str);

	if ( rb_obj_is_kind_of(self, rb_cPGconn) ) {
		to = PQescapeByteaConn(pg_get_pgconn(self), from, from_len, &to_len);
	} else {
		to = PQescapeBytea( from, from_len, &to_len);
	}

	ret = rb_str_new((char*)to, to_len - 1);
	PQfreemem(to);
	return ret;
}

.escape_string(str) ⇒ String

Returns a SQL-safe version of the String str. This is the preferred way to make strings safe for inclusion in SQL queries.

Consider using exec_params, which avoids the need for passing values inside of SQL commands.

Character encoding of escaped string will be equal to client encoding of connection.

NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.

See also convenience functions #escape_literal and #escape_identifier which also add proper quotes around the string.

Returns:

  • (String)


1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
# File 'ext/pg_connection.c', line 1627

static VALUE
pgconn_s_escape(VALUE self, VALUE string)
{
	size_t size;
	int error;
	VALUE result;
	int enc_idx;
	int singleton = !rb_obj_is_kind_of(self, rb_cPGconn);

	StringValueCStr(string);
	enc_idx = singleton ? ENCODING_GET(string) : pg_get_connection(self)->enc_idx;
	if( ENCODING_GET(string) != enc_idx ){
		string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx));
	}

	result = rb_str_new(NULL, RSTRING_LEN(string) * 2 + 1);
	PG_ENCODING_SET_NOCHECK(result, enc_idx);
	if( !singleton ) {
		size = PQescapeStringConn(pg_get_pgconn(self), RSTRING_PTR(result),
			RSTRING_PTR(string), RSTRING_LEN(string), &error);
		if(error)
			pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(pg_get_pgconn(self)));

	} else {
		size = PQescapeString(RSTRING_PTR(result), RSTRING_PTR(string), RSTRING_LEN(string));
	}
	rb_str_set_len(result, size);

	return result;
}

.new(*args) ⇒ Object Also known as: async_connect, connect, open, setdb, setdblogin

call-seq:

PG::Connection.new -> conn
PG::Connection.new(connection_hash) -> conn
PG::Connection.new(connection_string) -> conn
PG::Connection.new(host, port, options, tty, dbname, user, password) ->  conn

Create a connection to the specified server.

connection_hash must be a ruby Hash with connection parameters. See the list of valid parameters in the PostgreSQL documentation.

There are two accepted formats for connection_string: plain keyword = value strings and URIs. See the documentation of connection strings.

The positional parameter form has the same functionality except that the missing parameters will always take on default values. The parameters are:

host

server hostname

port

server port number

options

backend options

tty

(ignored in all versions of PostgreSQL)

dbname

connecting database name

user

login user name

password

login password

Examples:

# Connect using all defaults
PG::Connection.new

# As a Hash
PG::Connection.new( dbname: 'test', port: 5432 )

# As a String
PG::Connection.new( "dbname=test port=5432" )

# As an Array
PG::Connection.new( nil, 5432, nil, nil, 'test', nil, nil )

# As an URI
PG::Connection.new( "postgresql://user:[email protected]:5432/testdb?sslmode=require" )

If the Ruby default internal encoding is set (i.e., Encoding.default_internal != nil), the connection will have its client_encoding set accordingly.

Raises a PG::Error if the connection fails.



763
764
765
766
767
768
769
770
771
772
773
774
# File 'lib/pg/connection.rb', line 763

def new(*args)
	conn = connect_to_hosts(*args)

	if block_given?
		begin
			return yield conn
		ensure
			conn.finish
		end
	end
	conn
end

.parse_connect_args(*args) ⇒ Object

Parse the connection args into a connection-parameter string. See PG::Connection.new for valid arguments.

It accepts:

  • an option String kind of “host=name port=5432”

  • an option Hash kind of “name”, port: 5432

  • URI string

  • URI object

  • positional arguments

The method adds the option “fallback_application_name” if it isn’t already set. It returns a connection string with “key=value” pairs.



64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
# File 'lib/pg/connection.rb', line 64

def self.parse_connect_args( *args )
	hash_arg = args.last.is_a?( Hash ) ? args.pop.transform_keys(&:to_sym) : {}
	iopts = {}

	if args.length == 1
		case args.first.to_s
		when /=/, /:\/\//
			# Option or URL string style
			conn_string = args.first.to_s
			iopts = PG::Connection.conninfo_parse(conn_string).each_with_object({}){|h, o| o[h[:keyword].to_sym] = h[:val] if h[:val] }
		else
			# Positional parameters (only host given)
			iopts[CONNECT_ARGUMENT_ORDER.first.to_sym] = args.first
		end
	else
		# Positional parameters with host and more
		max = CONNECT_ARGUMENT_ORDER.length
		raise ArgumentError,
				"Extra positional parameter %d: %p" % [ max + 1, args[max] ] if args.length > max

		CONNECT_ARGUMENT_ORDER.zip( args ) do |(k,v)|
			iopts[ k.to_sym ] = v if v
		end
		iopts.delete(:tty) # ignore obsolete tty parameter
	end

	iopts.merge!( hash_arg )

	if !iopts[:fallback_application_name]
		iopts[:fallback_application_name] = PROGRAM_NAME.sub( /^(.{30}).{4,}(.{30})$/ ){ $1+"..."+$2 }
	end

	return connect_hash_to_string(iopts)
end

.ping(*args) ⇒ Object Also known as: async_ping

call-seq:

PG::Connection.ping(connection_hash)       -> Integer
PG::Connection.ping(connection_string)     -> Integer
PG::Connection.ping(host, port, options, tty, dbname, login, password) ->  Integer

PQpingParams reports the status of the server.

It accepts connection parameters identical to those of PQ::Connection.new . It is not necessary to supply correct user name, password, or database name values to obtain the server status; however, if incorrect values are provided, the server will log a failed connection attempt.

See PG::Connection.new for a description of the parameters.

Returns one of:

PQPING_OK

server is accepting connections

PQPING_REJECT

server is alive but rejecting connections

PQPING_NO_RESPONSE

could not establish connection

PQPING_NO_ATTEMPT

connection not attempted (bad params)

See also check_socket for a way to check the connection without doing any server communication.



867
868
869
870
871
872
873
874
875
# File 'lib/pg/connection.rb', line 867

def ping(*args)
	if Fiber.respond_to?(:scheduler) && Fiber.scheduler
		# Run PQping in a second thread to avoid blocking of the scheduler.
		# Unfortunately there's no nonblocking way to run ping.
		Thread.new { sync_ping(*args) }.value
	else
		sync_ping(*args)
	end
end

.quote_connstr(value) ⇒ Object

Quote a single value for use in a connection-parameter string.



37
38
39
# File 'lib/pg/connection.rb', line 37

def self.quote_connstr( value )
	return "'" + value.to_s.gsub( /[\\']/ ) {|m| '\\' + m } + "'"
end

.quote_ident(str) ⇒ String .quote_ident(array) ⇒ String .PG::Connection.quote_ident(str) ⇒ String .PG::Connection.quote_ident(array) ⇒ String

Returns a string that is safe for inclusion in a SQL query as an identifier. Note: this is not a quote function for values, but for identifiers.

For example, in a typical SQL query: SELECT FOO FROM MYTABLE The identifier FOO is folded to lower case, so it actually means foo. If you really want to access the case-sensitive field name FOO, use this function like conn.quote_ident('FOO'), which will return "FOO" (with double-quotes). PostgreSQL will see the double-quotes, and it will not fold to lower case.

Similarly, this function also protects against special characters, and other things that might allow SQL injection if the identifier comes from an untrusted source.

If the parameter is an Array, then all it’s values are separately quoted and then joined by a “.” character. This can be used for identifiers in the form “schema”.“table”.“column” .

This method is functional identical to the encoder PG::TextEncoder::Identifier .

If the instance method form is used and the input string character encoding is different to the connection encoding, then the string is converted to this encoding, so that the returned string is always encoded as PG::Connection#internal_encoding .

In the singleton form (PG::Connection.quote_ident) the character encoding of the result string is set to the character encoding of the input string.

Overloads:

  • .quote_ident(str) ⇒ String

    Returns:

    • (String)
  • .quote_ident(array) ⇒ String

    Returns:

    • (String)
  • .PG::Connection.quote_ident(str) ⇒ String

    Returns:

    • (String)
  • .PG::Connection.quote_ident(array) ⇒ String

    Returns:

    • (String)


3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
# File 'ext/pg_connection.c', line 3006

static VALUE
pgconn_s_quote_ident(VALUE self, VALUE str_or_array)
{
	VALUE ret;
	int enc_idx;

	if( rb_obj_is_kind_of(self, rb_cPGconn) ){
		enc_idx = pg_get_connection(self)->enc_idx;
	}else{
		enc_idx = RB_TYPE_P(str_or_array, T_STRING) ? ENCODING_GET( str_or_array ) : rb_ascii8bit_encindex();
	}
	pg_text_enc_identifier(NULL, str_or_array, NULL, &ret, enc_idx);

	return ret;
}

.sync_connect(*args) ⇒ Object



271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
# File 'ext/pg_connection.c', line 271

static VALUE
pgconn_s_sync_connect(int argc, VALUE *argv, VALUE klass)
{
	t_pg_connection *this;
	VALUE conninfo;
	VALUE self = pgconn_s_allocate( klass );

	this = pg_get_connection( self );
	conninfo = rb_funcall2( rb_cPGconn, rb_intern("parse_connect_args"), argc, argv );
	this->pgconn = gvl_PQconnectdb(StringValueCStr(conninfo));

	if(this->pgconn == NULL)
		rb_raise(rb_ePGerror, "PQconnectdb() unable to allocate PGconn structure");

	if (PQstatus(this->pgconn) == CONNECTION_BAD)
		pg_raise_conn_error( rb_eConnectionBad, self, "%s", PQerrorMessage(this->pgconn));

	pgconn_set_default_encoding( self );

	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, self, pgconn_finish, self);
	}
	return self;
}

.sync_ping(*args) ⇒ Object



342
343
344
345
346
347
348
349
350
351
352
# File 'ext/pg_connection.c', line 342

static VALUE
pgconn_s_sync_ping( int argc, VALUE *argv, VALUE klass )
{
	PGPing ping;
	VALUE conninfo;

	conninfo = rb_funcall2( klass, rb_intern("parse_connect_args"), argc, argv );
	ping     = gvl_PQping( StringValueCStr(conninfo) );

	return INT2FIX((int)ping);
}

.PG::Connection.unescape_bytea(string) ⇒ Object

Converts an escaped string representation of binary data into binary data — the reverse of #escape_bytea. This is needed when retrieving bytea data in text format, but not when retrieving it in binary format.



1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
# File 'ext/pg_connection.c', line 1713

static VALUE
pgconn_s_unescape_bytea(VALUE self, VALUE str)
{
	unsigned char *from, *to;
	size_t to_len;
	VALUE ret;

	UNUSED( self );

	Check_Type(str, T_STRING);
	from = (unsigned char*)StringValueCStr(str);

	to = PQunescapeBytea(from, &to_len);

	ret = rb_str_new((char*)to, to_len);
	PQfreemem(to);
	return ret;
}

Instance Method Details

#backend_keyInteger

Returns the key of the backend server process for this connection. This key can be used to cancel queries on the server.

Returns:

  • (Integer)


1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
# File 'ext/pg_connection.c', line 1010

static VALUE
pgconn_backend_key(VALUE self)
{
	int be_key;
	struct pg_cancel *cancel;
	PGconn *conn = pg_get_pgconn(self);

	cancel = (struct pg_cancel*)PQgetCancel(conn);
	if(cancel == NULL)
		pg_raise_conn_error( rb_ePGerror, self, "Invalid connection!");

	if( cancel->be_pid != PQbackendPID(conn) )
		rb_raise(rb_ePGerror,"Unexpected binary struct layout - please file a bug report at ruby-pg!");

	be_key = cancel->be_key;

	PQfreeCancel(cancel);

	return INT2NUM(be_key);
}

#backend_pidInteger

Returns the process ID of the backend server process for this connection. Note that this is a PID on database server host.

Returns:

  • (Integer)


980
981
982
983
984
# File 'ext/pg_connection.c', line 980

static VALUE
pgconn_backend_pid(VALUE self)
{
	return INT2NUM(PQbackendPID(pg_get_pgconn(self)));
}

#block([ timeout ]) ⇒ Boolean

Blocks until the server is no longer busy, or until the optional timeout is reached, whichever comes first. timeout is measured in seconds and can be fractional.

Returns false if timeout is reached, true otherwise.

If true is returned, conn.is_busy will return false and conn.get_result will not block.

Returns:

  • (Boolean)


3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
# File 'ext/pg_connection.c', line 3043

VALUE
pgconn_block( int argc, VALUE *argv, VALUE self ) {
	struct timeval timeout;
	struct timeval *ptimeout = NULL;
	VALUE timeout_in;
	double timeout_sec;
	void *ret;

	if ( rb_scan_args(argc, argv, "01", &timeout_in) == 1 ) {
		timeout_sec = NUM2DBL( timeout_in );
		timeout.tv_sec = (time_t)timeout_sec;
		timeout.tv_usec = (suseconds_t)((timeout_sec - (long)timeout_sec) * 1e6);
		ptimeout = &timeout;
	}

	ret = wait_socket_readable( self, ptimeout, get_result_readable);

	if( !ret )
		return Qfalse;

	return Qtrue;
}

#cancelObject Also known as: async_cancel

call-seq:

conn.cancel() -> String

Requests cancellation of the command currently being processed.

Returns nil on success, or a string containing the error message if a failure occurs.



587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
# File 'lib/pg/connection.rb', line 587

def cancel
	be_pid = backend_pid
	be_key = backend_key
	cancel_request = [0x10, 1234, 5678, be_pid, be_key].pack("NnnNN")

	if Fiber.respond_to?(:scheduler) && Fiber.scheduler && RUBY_PLATFORM =~ /mingw|mswin/
		# Ruby's nonblocking IO is not really supported on Windows.
		# We work around by using threads and explicit calls to wait_readable/wait_writable.
		cl = Thread.new(socket_io.remote_address) { |ra| ra.connect }.value
		begin
			cl.write_nonblock(cancel_request)
		rescue IO::WaitReadable, Errno::EINTR
			cl.wait_writable
			retry
		end
		begin
			cl.read_nonblock(1)
		rescue IO::WaitReadable, Errno::EINTR
			cl.wait_readable
			retry
		rescue EOFError
		end
	elsif RUBY_ENGINE == 'truffleruby'
		begin
			cl = socket_io.remote_address.connect
		rescue NotImplementedError
			# Workaround for truffleruby < 21.3.0
			cl2 = Socket.for_fd(socket_io.fileno)
			cl2.autoclose = false
			adr = cl2.remote_address
			if adr.ip?
				cl = TCPSocket.new(adr.ip_address, adr.ip_port)
				cl.autoclose = false
			else
				cl = UNIXSocket.new(adr.unix_path)
				cl.autoclose = false
			end
		end
		cl.write(cancel_request)
		cl.read(1)
	else
		cl = socket_io.remote_address.connect
		# Send CANCEL_REQUEST_CODE and parameters
		cl.write(cancel_request)
		# Wait for the postmaster to close the connection, which indicates that it's processed the request.
		cl.read(1)
	end

	cl.close
	nil
rescue SystemCallError => err
	err.to_s
end

#check_socketObject

Read all pending socket input to internal memory and raise an exception in case of errors.

This verifies that the connection socket is in a usable state and not aborted in any way. No communication is done with the server. Only pending data is read from the socket - the method doesn’t wait for any outstanding server answers.

Raises a kind of PG::Error if there was an error reading the data or if the socket is in a failure state.

The method doesn’t verify that the server is still responding. To verify that the communication to the server works, it is recommended to use something like conn.exec('') instead.



379
380
381
382
383
384
# File 'lib/pg/connection.rb', line 379

def check_socket
	while socket_io.wait_readable(0)
		consume_input
	end
	nil
end

#conndefaultsObject

Returns an array of Hashes with connection defaults. See ::conndefaults for details.



321
322
323
# File 'lib/pg/connection.rb', line 321

def conndefaults
	return self.class.conndefaults
end

#conndefaults_hashObject

Returns a Hash with connection defaults. See ::conndefaults_hash for details.



337
338
339
# File 'lib/pg/connection.rb', line 337

def conndefaults_hash
	return self.class.conndefaults_hash
end

#connect_pollInteger

Returns one of:

PGRES_POLLING_READING

wait until the socket is ready to read

PGRES_POLLING_WRITING

wait until the socket is ready to write

PGRES_POLLING_FAILED

the asynchronous connection has failed

PGRES_POLLING_OK

the asynchronous connection is ready

Example:

require "io/wait"

conn = PG::Connection.connect_start(dbname: 'mydatabase')
status = conn.connect_poll
while(status != PG::PGRES_POLLING_OK) do
  # do some work while waiting for the connection to complete
  if(status == PG::PGRES_POLLING_READING)
    unless conn.socket_io.wait_readable(10.0)
      raise "Asynchronous connection timed out!"
    end
  elsif(status == PG::PGRES_POLLING_WRITING)
    unless conn.socket_io.wait_writable(10.0)
      raise "Asynchronous connection timed out!"
    end
  end
  status = conn.connect_poll
end
# now conn.status == CONNECTION_OK, and connection
# is ready.

Returns:

  • (Integer)


514
515
516
517
518
519
520
521
522
523
# File 'ext/pg_connection.c', line 514

static VALUE
pgconn_connect_poll(VALUE self)
{
	PostgresPollingStatusType status;
	status = gvl_PQconnectPoll(pg_get_pgconn(self));

	pgconn_close_socket_io(self);

	return INT2FIX((int)status);
}

#connection_needs_passwordBoolean

Returns true if the authentication method required a password, but none was available. false otherwise.

Returns:

  • (Boolean)


1038
1039
1040
1041
1042
# File 'ext/pg_connection.c', line 1038

static VALUE
pgconn_connection_needs_password(VALUE self)
{
	return PQconnectionNeedsPassword(pg_get_pgconn(self)) ? Qtrue : Qfalse;
}

#connection_used_passwordBoolean

Returns true if the authentication method used a caller-supplied password, false otherwise.

Returns:

  • (Boolean)


1051
1052
1053
1054
1055
# File 'ext/pg_connection.c', line 1051

static VALUE
pgconn_connection_used_password(VALUE self)
{
	return PQconnectionUsedPassword(pg_get_pgconn(self)) ? Qtrue : Qfalse;
}

#conninfoHash

Returns the connection options used by a live connection.

Available since PostgreSQL-9.3

Returns:

  • (Hash)


764
765
766
767
768
769
770
771
772
773
774
# File 'ext/pg_connection.c', line 764

static VALUE
pgconn_conninfo( VALUE self )
{
	PGconn *conn = pg_get_pgconn(self);
	PQconninfoOption *options = PQconninfo( conn );
	VALUE array = pgconn_make_conninfo_array( options );

	PQconninfoFree(options);

	return array;
}

#conninfo_hashObject

Return the Postgres connection info structure as a Hash keyed by option keyword (as a Symbol).

See also #conninfo



345
346
347
348
349
# File 'lib/pg/connection.rb', line 345

def conninfo_hash
	return self.conninfo.each_with_object({}) do |info, hash|
		hash[ info[:keyword].to_sym ] = info[:val]
	end
end

#consume_inputObject

If input is available from the server, consume it. After calling consume_input, you can check is_busy or notifies to see if the state has changed.



2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
# File 'ext/pg_connection.c', line 2143

static VALUE
pgconn_consume_input(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	/* returns 0 on error */
	if(PQconsumeInput(conn) == 0) {
		pgconn_close_socket_io(self);
		pg_raise_conn_error( rb_eConnectionBad, self, "%s", PQerrorMessage(conn));
	}

	return Qnil;
}

#copy_data(sql, coder = nil) ⇒ Object

call-seq:

conn.copy_data( sql [, coder] ) {|sql_result| ... } -> PG::Result

Execute a copy process for transferring data to or from the server.

This issues the SQL COPY command via #exec. The response to this (if there is no error in the command) is a PG::Result object that is passed to the block, bearing a status code of PGRES_COPY_OUT or PGRES_COPY_IN (depending on the specified copy direction). The application should then use #put_copy_data or #get_copy_data to receive or transmit data rows and should return from the block when finished.

#copy_data returns another PG::Result object when the data transfer is complete. An exception is raised if some problem was encountered, so it isn’t required to make use of any of them. At this point further SQL commands can be issued via #exec. (It is not possible to execute other SQL commands using the same connection while the COPY operation is in progress.)

This method ensures, that the copy process is properly terminated in case of client side or server side failures. Therefore, in case of blocking mode of operation, #copy_data is preferred to raw calls of #put_copy_data, #get_copy_data and #put_copy_end.

coder can be a PG::Coder derivation (typically PG::TextEncoder::CopyRow or PG::TextDecoder::CopyRow). This enables encoding of data fields given to #put_copy_data or decoding of fields received by #get_copy_data.

Example with CSV input format:

conn.exec "create table my_table (a text,b text,c text,d text)"
conn.copy_data "COPY my_table FROM STDIN CSV" do
  conn.put_copy_data "some,data,to,copy\n"
  conn.put_copy_data "more,data,to,copy\n"
end

This creates my_table and inserts two CSV rows.

The same with text format encoder PG::TextEncoder::CopyRow and Array input:

enco = PG::TextEncoder::CopyRow.new
conn.copy_data "COPY my_table FROM STDIN", enco do
  conn.put_copy_data ['some', 'data', 'to', 'copy']
  conn.put_copy_data ['more', 'data', 'to', 'copy']
end

Also PG::BinaryEncoder::CopyRow can be used to send data in binary format to the server. In this case copy_data generates the header and trailer data automatically:

enco = PG::BinaryEncoder::CopyRow.new
conn.copy_data "COPY my_table FROM STDIN (FORMAT binary)", enco do
  conn.put_copy_data ['some', 'data', 'to', 'copy']
  conn.put_copy_data ['more', 'data', 'to', 'copy']
end

Example with CSV output format:

conn.copy_data "COPY my_table TO STDOUT CSV" do
  while row=conn.get_copy_data
    p row
  end
end

This prints all rows of my_table to stdout:

"some,data,to,copy\n"
"more,data,to,copy\n"

The same with text format decoder PG::TextDecoder::CopyRow and Array output:

deco = PG::TextDecoder::CopyRow.new
conn.copy_data "COPY my_table TO STDOUT", deco do
  while row=conn.get_copy_data
    p row
  end
end

This receives all rows of my_table as ruby array:

["some", "data", "to", "copy"]
["more", "data", "to", "copy"]

Also PG::BinaryDecoder::CopyRow can be used to retrieve data in binary format from the server. In this case the header and trailer data is processed by the decoder and the remaining nil from get_copy_data is processed by copy_data, so that binary data can be processed equally to text data:

deco = PG::BinaryDecoder::CopyRow.new
conn.copy_data "COPY my_table TO STDOUT (FORMAT binary)", deco do
  while row=conn.get_copy_data
    p row
  end
end

This receives all rows of my_table as ruby array:

["some", "data", "to", "copy"]
["more", "data", "to", "copy"]


211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
# File 'lib/pg/connection.rb', line 211

def copy_data( sql, coder=nil )
	raise PG::NotInBlockingMode.new("copy_data can not be used in nonblocking mode", connection: self) if nonblocking?
	res = exec( sql )

	case res.result_status
	when PGRES_COPY_IN
		begin
			if coder && res.binary_tuples == 1
				# Binary file header (11 byte signature, 32 bit flags and 32 bit extension length)
				put_copy_data(BinarySignature + ("\x00" * 8))
			end

			if coder
				old_coder = self.encoder_for_put_copy_data
				self.encoder_for_put_copy_data = coder
			end

			yield res
		rescue Exception => err
			errmsg = "%s while copy data: %s" % [ err.class.name, err.message ]
			begin
				put_copy_end( errmsg )
			rescue PG::Error
				# Ignore error in cleanup to avoid losing original exception
			end
			discard_results
			raise err
		else
			begin
				self.encoder_for_put_copy_data = old_coder if coder

				if coder && res.binary_tuples == 1
					put_copy_data("\xFF\xFF") # Binary file trailer 16 bit "-1"
				end

				put_copy_end
			rescue PG::Error => err
				raise PG::LostCopyState.new("#{err} (probably by executing another SQL query while running a COPY command)", connection: self)
			end
			get_last_result
		ensure
			self.encoder_for_put_copy_data = old_coder if coder
		end

	when PGRES_COPY_OUT
		begin
			if coder
				old_coder = self.decoder_for_get_copy_data
				self.decoder_for_get_copy_data = coder
			end
			yield res
		rescue Exception
			cancel
			discard_results
			raise
		else
			if coder && res.binary_tuples == 1
				# There are two end markers in binary mode: file trailer and the final nil.
				# The file trailer is expected to be processed by BinaryDecoder::CopyRow and already returns nil, so that the remaining NULL from PQgetCopyData is retrieved here:
				if get_copy_data
					discard_results
					raise PG::NotAllCopyDataRetrieved.new("Not all binary COPY data retrieved", connection: self)
				end
			end
			res = get_last_result
			if !res
				discard_results
				raise PG::LostCopyState.new("Lost COPY state (probably by executing another SQL query while running a COPY command)", connection: self)
			elsif res.result_status != PGRES_COMMAND_OK
				discard_results
				raise PG::NotAllCopyDataRetrieved.new("Not all COPY data retrieved", connection: self)
			end
			res
		ensure
			self.decoder_for_get_copy_data = old_coder if coder
		end

	else
		raise ArgumentError, "SQL command is no COPY statement: #{sql}"
	end
end

#dbObject

Returns the connected database name.



632
633
634
635
636
637
638
# File 'ext/pg_connection.c', line 632

static VALUE
pgconn_db(VALUE self)
{
	char *db = PQdb(pg_get_pgconn(self));
	if (!db) return Qnil;
	return rb_str_new2(db);
}

#decoder_for_get_copy_dataPG::Coder

Returns the default coder object that is currently set for type casting of received data by #get_copy_data .

Returns either:

  • a kind of PG::Coder

  • nil - type encoding is disabled, returned data will be a String.

Returns:



4389
4390
4391
4392
4393
4394
4395
# File 'ext/pg_connection.c', line 4389

static VALUE
pgconn_decoder_for_get_copy_data_get(VALUE self)
{
	t_pg_connection *this = pg_get_connection( self );

	return this->decoder_for_get_copy_data;
}

#decoder_for_get_copy_data=(decoder) ⇒ Object

Set the default coder that is used for type casting of received data by #get_copy_data .

decoder can be:

  • a kind of PG::Coder

  • nil - disable type decoding, returned data will be a String.



4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
# File 'ext/pg_connection.c', line 4360

static VALUE
pgconn_decoder_for_get_copy_data_set(VALUE self, VALUE decoder)
{
	t_pg_connection *this = pg_get_connection( self );

	rb_check_frozen(self);
	if( decoder != Qnil ){
		t_pg_coder *co;
		UNUSED(co);
		/* Check argument type */
		TypedData_Get_Struct(decoder, t_pg_coder, &pg_coder_type, co);
	}
	RB_OBJ_WRITE(self, &this->decoder_for_get_copy_data, decoder);

	return decoder;
}

#describe_portal(portal_name) ⇒ PG::Result Also known as: async_describe_portal

Retrieve information about the portal portal_name.

See also corresponding libpq function.

Returns:



3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
# File 'ext/pg_connection.c', line 3461

static VALUE
pgconn_async_describe_portal(VALUE self, VALUE portal)
{
	VALUE rb_pgresult = Qnil;

	pgconn_discard_results( self );
	pgconn_send_describe_portal( self, portal );
	rb_pgresult = pgconn_async_get_last_result( self );

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_pgresult, pg_result_clear, rb_pgresult );
	}
	return rb_pgresult;
}

#describe_prepared(statement_name) ⇒ PG::Result Also known as: async_describe_prepared

Retrieve information about the prepared statement statement_name.

See also corresponding libpq function.

Returns:



3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
# File 'ext/pg_connection.c', line 3485

static VALUE
pgconn_async_describe_prepared(VALUE self, VALUE stmt_name)
{
	VALUE rb_pgresult = Qnil;

	pgconn_discard_results( self );
	pgconn_send_describe_prepared( self, stmt_name );
	rb_pgresult = pgconn_async_get_last_result( self );

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_pgresult, pg_result_clear, rb_pgresult );
	}
	return rb_pgresult;
}

#discard_resultsObject

Silently discard any prior query result that application didn’t eat. This is internally used prior to Connection#exec and sibling methods. It doesn’t raise an exception on connection errors, but returns false instead.

Returns:

  • nil when the connection is already idle

  • true when some results have been discarded

  • false when a failure occured and the connection was closed



3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
# File 'ext/pg_connection.c', line 3168

static VALUE
pgconn_discard_results(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	VALUE socket_io;

	switch( PQtransactionStatus(conn) ) {
		case PQTRANS_IDLE:
		case PQTRANS_INTRANS:
		case PQTRANS_INERROR:
			return Qnil;
		default:;
	}

	socket_io = pgconn_socket_io(self);

	for(;;) {
		PGresult *cur;
		int status;

		/* pgconn_block() raises an exception in case of errors.
		* To avoid this call pg_rb_io_wait() and PQconsumeInput() without rb_raise().
		*/
		while( gvl_PQisBusy(conn) ){
			int events;

			switch( PQflush(conn) ) {
				case 1:
					events = RB_NUM2INT(pg_rb_io_wait(socket_io, RB_INT2NUM(PG_RUBY_IO_READABLE | PG_RUBY_IO_WRITABLE), Qnil));
					if (events & PG_RUBY_IO_READABLE){
						if ( PQconsumeInput(conn) == 0 ) goto error;
					}
					break;
				case 0:
					pg_rb_io_wait(socket_io, RB_INT2NUM(PG_RUBY_IO_READABLE), Qnil);
					if ( PQconsumeInput(conn) == 0 ) goto error;
					break;
				default:
					goto error;
			}
		}

		cur = gvl_PQgetResult(conn);
		if( cur == NULL) break;

		status = PQresultStatus(cur);
		PQclear(cur);
		if (status == PGRES_COPY_IN){
			while( gvl_PQputCopyEnd(conn, "COPY terminated by new query or discard_results") == 0 ){
				pgconn_async_flush(self);
			}
		}
		if (status == PGRES_COPY_OUT){
			for(;;) {
				char *buffer = NULL;
				int st = gvl_PQgetCopyData(conn, &buffer, 1);
				if( st == 0 ) {
					/* would block -> wait for readable data */
					pg_rb_io_wait(socket_io, RB_INT2NUM(PG_RUBY_IO_READABLE), Qnil);
					if ( PQconsumeInput(conn) == 0 ) goto error;
				} else if( st > 0 ) {
					/* some data retrieved -> discard it */
					PQfreemem(buffer);
				} else {
					/* no more data */
					break;
				}
			}
		}
	}

	return Qtrue;

error:
	pgconn_close_socket_io(self);
	return Qfalse;
}

#encoder_for_put_copy_dataPG::Coder

Returns the default coder object that is currently set for type casting of parameters to #put_copy_data .

Returns either:

  • a kind of PG::Coder

  • nil - type encoding is disabled, data must be a String.

Returns:



4340
4341
4342
4343
4344
4345
4346
# File 'ext/pg_connection.c', line 4340

static VALUE
pgconn_encoder_for_put_copy_data_get(VALUE self)
{
	t_pg_connection *this = pg_get_connection( self );

	return this->encoder_for_put_copy_data;
}

#encoder_for_put_copy_data=(encoder) ⇒ Object

Set the default coder that is used for type casting of parameters to #put_copy_data .

encoder can be:

  • a kind of PG::Coder

  • nil - disable type encoding, data must be a String.



4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
# File 'ext/pg_connection.c', line 4311

static VALUE
pgconn_encoder_for_put_copy_data_set(VALUE self, VALUE encoder)
{
	t_pg_connection *this = pg_get_connection( self );

	rb_check_frozen(self);
	if( encoder != Qnil ){
		t_pg_coder *co;
		UNUSED(co);
		/* Check argument type */
		TypedData_Get_Struct(encoder, t_pg_coder, &pg_coder_type, co);
	}
	RB_OBJ_WRITE(self, &this->encoder_for_put_copy_data, encoder);

	return encoder;
}

#encrypt_password(password, username, algorithm = nil) ⇒ Object Also known as: async_encrypt_password

call-seq:

conn.encrypt_password( password, username, algorithm=nil ) -> String

This function is intended to be used by client applications that wish to send commands like ALTER USER joe PASSWORD 'pwd'. It is good practice not to send the original cleartext password in such a command, because it might be exposed in command logs, activity displays, and so on. Instead, use this function to convert the password to encrypted form before it is sent.

The password and username arguments are the cleartext password, and the SQL name of the user it is for. algorithm specifies the encryption algorithm to use to encrypt the password. Currently supported algorithms are md5 and scram-sha-256 (on and off are also accepted as aliases for md5, for compatibility with older server versions). Note that support for scram-sha-256 was introduced in PostgreSQL version 10, and will not work correctly with older server versions. If algorithm is omitted or nil, this function will query the server for the current value of the password_encryption setting. That can block, and will fail if the current transaction is aborted, or if the connection is busy executing another query. If you wish to use the default algorithm for the server but want to avoid blocking, query password_encryption yourself before calling #encrypt_password, and pass that value as the algorithm.

Return value is the encrypted password. The caller can assume the string doesn’t contain any special characters that would require escaping.

Available since PostgreSQL-10. See also corresponding libpq function.



555
556
557
558
# File 'lib/pg/connection.rb', line 555

def encrypt_password( password, username, algorithm=nil )
	algorithm ||= exec("SHOW password_encryption").getvalue(0,0)
	sync_encrypt_password(password, username, algorithm)
end

#enter_pipeline_modenil

Causes a connection to enter pipeline mode if it is currently idle or already in pipeline mode.

Raises PG::Error and has no effect if the connection is not currently idle, i.e., it has a result ready, or it is waiting for more input from the server, etc. This function does not actually send anything to the server, it just changes the libpq connection state.

Available since PostgreSQL-14

Returns:

  • (nil)


3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
# File 'ext/pg_connection.c', line 3615

static VALUE
pgconn_enter_pipeline_mode(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int res = PQenterPipelineMode(conn);
	if( res != 1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}

#error_messageString

Returns the error message most recently generated by an operation on the connection.

Nearly all libpq functions will set a message for conn.error_message if they fail. Note that by libpq convention, a nonempty error_message result can consist of multiple lines, and will include a trailing newline.

Returns:

  • (String)


885
886
887
888
889
890
891
# File 'ext/pg_connection.c', line 885

static VALUE
pgconn_error_message(VALUE self)
{
	char *error = PQerrorMessage(pg_get_pgconn(self));
	if (!error) return Qnil;
	return rb_str_new2(error);
}

#escape_bytea(string) ⇒ String

Escapes binary data for use within an SQL command with the type bytea.

Certain byte values must be escaped (but all byte values may be escaped) when used as part of a bytea literal in an SQL statement. In general, to escape a byte, it is converted into the three digit octal number equal to the octet value, and preceded by two backslashes. The single quote (‘) and backslash () characters have special alternative escape sequences. #escape_bytea performs this operation, escaping only the minimally required bytes.

Consider using exec_params, which avoids the need for passing values inside of SQL commands.

NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.

Returns:

  • (String)


1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
# File 'ext/pg_connection.c', line 1681

static VALUE
pgconn_s_escape_bytea(VALUE self, VALUE str)
{
	unsigned char *from, *to;
	size_t from_len, to_len;
	VALUE ret;

	Check_Type(str, T_STRING);
	from      = (unsigned char*)RSTRING_PTR(str);
	from_len  = RSTRING_LEN(str);

	if ( rb_obj_is_kind_of(self, rb_cPGconn) ) {
		to = PQescapeByteaConn(pg_get_pgconn(self), from, from_len, &to_len);
	} else {
		to = PQescapeBytea( from, from_len, &to_len);
	}

	ret = rb_str_new((char*)to, to_len - 1);
	PQfreemem(to);
	return ret;
}

#escape_identifier(str) ⇒ String

Escape an arbitrary String str as an identifier.

This method does the same as #quote_ident with a String argument, but it doesn’t support an Array argument and it makes use of libpq to process the string.

Returns:

  • (String)


1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
# File 'ext/pg_connection.c', line 1774

static VALUE
pgconn_escape_identifier(VALUE self, VALUE string)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	char *escaped = NULL;
	VALUE result = Qnil;
	int enc_idx = this->enc_idx;

	StringValueCStr(string);
	if( ENCODING_GET(string) != enc_idx ){
		string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx));
	}

	escaped = PQescapeIdentifier(this->pgconn, RSTRING_PTR(string), RSTRING_LEN(string));
	if (escaped == NULL)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(this->pgconn));

	result = rb_str_new2(escaped);
	PQfreemem(escaped);
	PG_ENCODING_SET_NOCHECK(result, enc_idx);

	return result;
}

#escape_literal(str) ⇒ String

Escape an arbitrary String str as a literal.

See also PG::TextEncoder::QuotedLiteral for a type cast integrated version of this function.

Returns:

  • (String)


1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
# File 'ext/pg_connection.c', line 1740

static VALUE
pgconn_escape_literal(VALUE self, VALUE string)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	char *escaped = NULL;
	VALUE result = Qnil;
	int enc_idx = this->enc_idx;

	StringValueCStr(string);
	if( ENCODING_GET(string) != enc_idx ){
		string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx));
	}

	escaped = PQescapeLiteral(this->pgconn, RSTRING_PTR(string), RSTRING_LEN(string));
	if (escaped == NULL)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(this->pgconn));

	result = rb_str_new2(escaped);
	PQfreemem(escaped);
	PG_ENCODING_SET_NOCHECK(result, enc_idx);

	return result;
}

#escape_string(str) ⇒ String Also known as: escape

Returns a SQL-safe version of the String str. This is the preferred way to make strings safe for inclusion in SQL queries.

Consider using exec_params, which avoids the need for passing values inside of SQL commands.

Character encoding of escaped string will be equal to client encoding of connection.

NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.

See also convenience functions #escape_literal and #escape_identifier which also add proper quotes around the string.

Returns:

  • (String)


1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
# File 'ext/pg_connection.c', line 1627

static VALUE
pgconn_s_escape(VALUE self, VALUE string)
{
	size_t size;
	int error;
	VALUE result;
	int enc_idx;
	int singleton = !rb_obj_is_kind_of(self, rb_cPGconn);

	StringValueCStr(string);
	enc_idx = singleton ? ENCODING_GET(string) : pg_get_connection(self)->enc_idx;
	if( ENCODING_GET(string) != enc_idx ){
		string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx));
	}

	result = rb_str_new(NULL, RSTRING_LEN(string) * 2 + 1);
	PG_ENCODING_SET_NOCHECK(result, enc_idx);
	if( !singleton ) {
		size = PQescapeStringConn(pg_get_pgconn(self), RSTRING_PTR(result),
			RSTRING_PTR(string), RSTRING_LEN(string), &error);
		if(error)
			pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(pg_get_pgconn(self)));

	} else {
		size = PQescapeString(RSTRING_PTR(result), RSTRING_PTR(string), RSTRING_LEN(string));
	}
	rb_str_set_len(result, size);

	return result;
}

#exec(sql) ⇒ PG::Result #exec(sql) {|pg_result| ... } ⇒ Object Also known as: async_exec

Sends SQL query request specified by sql to PostgreSQL. On success, it returns a PG::Result instance with all result rows and columns. On failure, it raises a PG::Error.

For backward compatibility, if you pass more than one parameter to this method, it will call #exec_params for you. New code should explicitly use #exec_params if argument placeholders are used.

If the optional code block is given, it will be passed result as an argument, and the PG::Result object will automatically be cleared when the block terminates. In this instance, conn.exec returns the value of the block.

#exec is an alias for #async_exec which is almost identical to #sync_exec . #sync_exec is implemented on the simpler synchronous command processing API of libpq, whereas #async_exec is implemented on the asynchronous API and on ruby’s IO mechanisms. Only #async_exec is compatible to Fiber.scheduler based asynchronous IO processing introduced in ruby-3.0. Both methods ensure that other threads can process while waiting for the server to complete the request, but #sync_exec blocks all signals to be processed until the query is finished. This is most notably visible by a delayed reaction to Control+C. It’s not recommended to use explicit sync or async variants but #exec instead, unless you have a good reason to do so.

See also corresponding libpq function.

Overloads:

  • #exec(sql) ⇒ PG::Result

    Returns:

  • #exec(sql) {|pg_result| ... } ⇒ Object

    Yields:

    • (pg_result)


3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
# File 'ext/pg_connection.c', line 3274

static VALUE
pgconn_async_exec(int argc, VALUE *argv, VALUE self)
{
	VALUE rb_pgresult = Qnil;

	pgconn_discard_results( self );
	pgconn_send_query( argc, argv, self );
	rb_pgresult = pgconn_async_get_last_result( self );

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_pgresult, pg_result_clear, rb_pgresult );
	}
	return rb_pgresult;
}

#exec_params(sql, params[, result_format [, type_map ]]) ⇒ nil #exec_params(sql, params[, result_format [, type_map ]]) {|pg_result| ... } ⇒ Object Also known as: async_exec_params

Sends SQL query request specified by sql to PostgreSQL using placeholders for parameters.

Returns a PG::Result instance on success. On failure, it raises a PG::Error.

params is an array of the bind parameters for the SQL query. Each element of the params array may be either:

a hash of the form:
  {:value  => String (value of bind parameter)
   :type   => Integer (oid of type of bind parameter)
   :format => Integer (0 for text, 1 for binary)
  }
or, it may be a String. If it is a string, that is equivalent to the hash:
  { :value => <string value>, :type => 0, :format => 0 }

PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query. The 0th element of the params array is bound to $1, the 1st element is bound to $2, etc. nil is treated as NULL.

If the types are not specified, they will be inferred by PostgreSQL. Instead of specifying type oids, it’s recommended to simply add explicit casts in the query to ensure that the right type is used.

For example: “SELECT $1::int”

The optional result_format should be 0 for text results, 1 for binary.

type_map can be a PG::TypeMap derivation (such as PG::BasicTypeMapForQueries). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.

If the optional code block is given, it will be passed result as an argument, and the PG::Result object will automatically be cleared when the block terminates. In this instance, conn.exec returns the value of the block.

The primary advantage of #exec_params over #exec is that parameter values can be separated from the command string, thus avoiding the need for tedious and error-prone quoting and escaping. Unlike #exec, #exec_params allows at most one SQL command in the given string. (There can be semicolons in it, but not more than one nonempty command.) This is a limitation of the underlying protocol, but has some usefulness as an extra defense against SQL-injection attacks.

See also corresponding libpq function.

Overloads:

  • #exec_params(sql, params[, result_format [, type_map ]]) ⇒ nil

    Returns:

    • (nil)
  • #exec_params(sql, params[, result_format [, type_map ]]) {|pg_result| ... } ⇒ Object

    Yields:

    • (pg_result)


3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
# File 'ext/pg_connection.c', line 3340

static VALUE
pgconn_async_exec_params(int argc, VALUE *argv, VALUE self)
{
	VALUE rb_pgresult = Qnil;

	pgconn_discard_results( self );
	/* If called with no or nil parameters, use PQsendQuery for compatibility */
	if ( argc == 1 || (argc >= 2 && argc <= 4 && NIL_P(argv[1]) )) {
		pg_deprecated(3, ("forwarding async_exec_params to async_exec is deprecated"));
		pgconn_send_query( argc, argv, self );
	} else {
		pgconn_send_query_params( argc, argv, self );
	}
	rb_pgresult = pgconn_async_get_last_result( self );

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_pgresult, pg_result_clear, rb_pgresult );
	}
	return rb_pgresult;
}

#exec_prepared(statement_name[, params, result_format[, type_map]]) ⇒ PG::Result #exec_prepared(statement_name[, params, result_format[, type_map]]) {|pg_result| ... } ⇒ Object Also known as: async_exec_prepared

Execute prepared named statement specified by statement_name. Returns a PG::Result instance on success. On failure, it raises a PG::Error.

params is an array of the optional bind parameters for the SQL query. Each element of the params array may be either:

a hash of the form:
  {:value  => String (value of bind parameter)
   :format => Integer (0 for text, 1 for binary)
  }
or, it may be a String. If it is a string, that is equivalent to the hash:
  { :value => <string value>, :format => 0 }

PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query. The 0th element of the params array is bound to $1, the 1st element is bound to $2, etc. nil is treated as NULL.

The optional result_format should be 0 for text results, 1 for binary.

type_map can be a PG::TypeMap derivation (such as PG::BasicTypeMapForQueries). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.

If the optional code block is given, it will be passed result as an argument, and the PG::Result object will automatically be cleared when the block terminates. In this instance, conn.exec_prepared returns the value of the block.

See also corresponding libpq function.

Overloads:

  • #exec_prepared(statement_name[, params, result_format[, type_map]]) ⇒ PG::Result

    Returns:

  • #exec_prepared(statement_name[, params, result_format[, type_map]]) {|pg_result| ... } ⇒ Object

    Yields:

    • (pg_result)


3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
# File 'ext/pg_connection.c', line 3437

static VALUE
pgconn_async_exec_prepared(int argc, VALUE *argv, VALUE self)
{
	VALUE rb_pgresult = Qnil;

	pgconn_discard_results( self );
	pgconn_send_query_prepared( argc, argv, self );
	rb_pgresult = pgconn_async_get_last_result( self );

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_pgresult, pg_result_clear, rb_pgresult );
	}
	return rb_pgresult;
}

#exit_pipeline_modenil

Causes a connection to exit pipeline mode if it is currently in pipeline mode with an empty queue and no pending results.

Takes no action if not in pipeline mode. Raises PG::Error if the current statement isn’t finished processing, or PQgetResult has not been called to collect results from all previously sent query.

Available since PostgreSQL-14

Returns:

  • (nil)


3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
# File 'ext/pg_connection.c', line 3637

static VALUE
pgconn_exit_pipeline_mode(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int res = PQexitPipelineMode(conn);
	if( res != 1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}

#external_encodingEncoding

Return the server_encoding of the connected database as a Ruby Encoding object. The SQL_ASCII encoding is mapped to to ASCII_8BIT.

Returns:

  • (Encoding)


4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
# File 'ext/pg_connection.c', line 4122

static VALUE
pgconn_external_encoding(VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	rb_encoding *enc = NULL;
	const char *pg_encname = NULL;

	pg_encname = PQparameterStatus( this->pgconn, "server_encoding" );
	enc = pg_get_pg_encname_as_rb_encoding( pg_encname );
	return rb_enc_from_encoding( enc );
}

#field_name_typeSymbol

Get type of field names.

See description at #field_name_type=

Returns:

  • (Symbol)


4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
# File 'ext/pg_connection.c', line 4436

static VALUE
pgconn_field_name_type_get(VALUE self)
{
	t_pg_connection *this = pg_get_connection( self );

	if( this->flags & PG_RESULT_FIELD_NAMES_SYMBOL ){
		return sym_symbol;
	} else if( this->flags & PG_RESULT_FIELD_NAMES_STATIC_SYMBOL ){
		return sym_static_symbol;
	} else {
		return sym_string;
	}
}

#field_name_type=(Symbol) ⇒ Object

Set default type of field names of results retrieved by this connection. It can be set to one of:

  • :string to use String based field names

  • :symbol to use Symbol based field names

The default is :string .

Settings the type of field names affects only future results.

See further description at PG::Result#field_name_type=



4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
# File 'ext/pg_connection.c', line 4413

static VALUE
pgconn_field_name_type_set(VALUE self, VALUE sym)
{
	t_pg_connection *this = pg_get_connection( self );

	rb_check_frozen(self);
	this->flags &= ~PG_RESULT_FIELD_NAMES_MASK;
	if( sym == sym_symbol ) this->flags |= PG_RESULT_FIELD_NAMES_SYMBOL;
	else if ( sym == sym_static_symbol ) this->flags |= PG_RESULT_FIELD_NAMES_STATIC_SYMBOL;
	else if ( sym == sym_string );
	else rb_raise(rb_eArgError, "invalid argument %+"PRIsVALUE, sym);

	return sym;
}

#finishObject Also known as: close

Closes the backend connection.



531
532
533
534
535
536
537
538
539
540
# File 'ext/pg_connection.c', line 531

static VALUE
pgconn_finish( VALUE self )
{
	t_pg_connection *this = pg_get_connection_safe( self );

	pgconn_close_socket_io( self );
	PQfinish( this->pgconn );
	this->pgconn = NULL;
	return Qnil;
}

#finished?Boolean

Returns true if the backend connection has been closed.

Returns:

  • (Boolean)


549
550
551
552
553
554
555
# File 'ext/pg_connection.c', line 549

static VALUE
pgconn_finished_p( VALUE self )
{
	t_pg_connection *this = pg_get_connection( self );
	if ( this->pgconn ) return Qfalse;
	return Qtrue;
}

#flushBoolean Also known as: async_flush

Attempts to flush any queued output data to the server. Returns true if data is successfully flushed, false if not. It can only return false if connection is in nonblocking mode. Raises PG::Error if some other failure occurred.

Returns:

  • (Boolean)


2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
# File 'ext/pg_connection.c', line 2464

static VALUE
pgconn_async_flush(VALUE self)
{
	while( pgconn_sync_flush(self) == Qfalse ){
		/* wait for the socket to become read- or write-ready */
		int events;
		VALUE socket_io = pgconn_socket_io(self);
		events = RB_NUM2INT(pg_rb_io_wait(socket_io, RB_INT2NUM(PG_RUBY_IO_READABLE | PG_RUBY_IO_WRITABLE), Qnil));

		if (events & PG_RUBY_IO_READABLE){
			pgconn_consume_input(self);
		}
	}
	return Qtrue;
}

#get_client_encodingString

Returns the client encoding as a String.

Returns:

  • (String)


2937
2938
2939
2940
2941
2942
# File 'ext/pg_connection.c', line 2937

static VALUE
pgconn_get_client_encoding(VALUE self)
{
	char *encoding = (char *)pg_encoding_to_char(PQclientEncoding(pg_get_pgconn(self)));
	return rb_str_new2(encoding);
}

#get_copy_data(async = false, decoder = nil) ⇒ Object Also known as: async_get_copy_data

call-seq:

conn.get_copy_data( [ nonblock = false [, decoder = nil ]] ) -> Object

Return one row of data, nil if the copy is done, or false if the call would block (only possible if nonblock is true).

If decoder is not set or nil, data is returned as binary string.

If decoder is set to a PG::Coder derivation, the return type depends on this decoder. PG::TextDecoder::CopyRow decodes the received data fields from one row of PostgreSQL’s COPY text format to an Array of Strings. Optionally the decoder can type cast the single fields to various Ruby types in one step, if PG::TextDecoder::CopyRow#type_map is set accordingly.

See also #copy_data.



423
424
425
426
427
428
429
430
431
432
433
# File 'lib/pg/connection.rb', line 423

def get_copy_data(async=false, decoder=nil)
	if async
		return sync_get_copy_data(async, decoder)
	else
		while (res=sync_get_copy_data(true, decoder)) == false
			socket_io.wait_readable
			consume_input
		end
		return res
	end
end

#get_last_resultPG::Result Also known as: async_get_last_result

This function retrieves all available results on the current connection (from previously issued asynchronous commands like send_query()) and returns the last non-NULL result, or nil if no results are available.

If the last result contains a bad result_status, an appropriate exception is raised.

This function is similar to #get_result except that it is designed to get one and only one result and that it checks the result state.

Returns:



3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
# File 'ext/pg_connection.c', line 3120

static VALUE
pgconn_async_get_last_result(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	VALUE rb_pgresult = Qnil;
	PGresult *cur, *prev;

	cur = prev = NULL;
	for(;;) {
		int status;

		/* wait for input (without blocking) before reading each result */
		wait_socket_readable(self, NULL, get_result_readable);

		cur = gvl_PQgetResult(conn);
		if (cur == NULL)
			break;

		if (prev) PQclear(prev);
		prev = cur;

		status = PQresultStatus(cur);
		if (status == PGRES_COPY_OUT || status == PGRES_COPY_IN || status == PGRES_COPY_BOTH)
			break;
	}

	if (prev) {
		rb_pgresult = pg_new_result( prev, self );
		pg_result_check(rb_pgresult);
	}

	return rb_pgresult;
}

#get_resultObject Also known as: async_get_result

call-seq:

conn.get_result() -> PG::Result
conn.get_result() {|pg_result| block }

Blocks waiting for the next result from a call to #send_query (or another asynchronous command), and returns it. Returns nil if no more results are available.

Note: call this function repeatedly until it returns nil, or else you will not be able to issue further commands.

If the optional code block is given, it will be passed result as an argument, and the PG::Result object will automatically be cleared when the block terminates. In this instance, conn.exec returns the value of the block.



400
401
402
403
# File 'lib/pg/connection.rb', line 400

def get_result
	block
	sync_get_result
end

#hostObject

Returns the server host name of the active connection. This can be a host name, an IP address, or a directory path if the connection is via Unix socket. (The path case can be distinguished because it will always be an absolute path, beginning with / .)

If the connection parameters specified both host and hostaddr, then host will return the host information. If only hostaddr was specified, then that is returned. If multiple hosts were specified in the connection parameters, host returns the host actually connected to.

If there is an error producing the host information (perhaps if the connection has not been fully established or there was an error), it returns an empty string.

If multiple hosts were specified in the connection parameters, it is not possible to rely on the result of host until the connection is established. The status of the connection can be checked using the function Connection#status .



685
686
687
688
689
690
691
# File 'ext/pg_connection.c', line 685

static VALUE
pgconn_host(VALUE self)
{
	char *host = PQhost(pg_get_pgconn(self));
	if (!host) return Qnil;
	return rb_str_new2(host);
}

#hostaddrObject

Returns the server IP address of the active connection. This can be the address that a host name resolved to, or an IP address provided through the hostaddr parameter. If there is an error producing the host information (perhaps if the connection has not been fully established or there was an error), it returns an empty string.



704
705
706
707
708
709
710
# File 'ext/pg_connection.c', line 704

static VALUE
pgconn_hostaddr(VALUE self)
{
	char *host = PQhostaddr(pg_get_pgconn(self));
	if (!host) return Qnil;
	return rb_str_new2(host);
}

#inspectObject

Return a String representation of the object suitable for debugging.



100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
# File 'lib/pg/connection.rb', line 100

def inspect
	str = self.to_s
	str[-1,0] = if finished?
		" finished"
	else
		stats = []
		stats << " status=#{ PG.constants.grep(/CONNECTION_/).find{|c| PG.const_get(c) == status} }" if status != CONNECTION_OK
		stats << " transaction_status=#{ PG.constants.grep(/PQTRANS_/).find{|c| PG.const_get(c) == transaction_status} }" if transaction_status != PG::PQTRANS_IDLE
		stats << " nonblocking=#{ isnonblocking }" if isnonblocking
		stats << " pipeline_status=#{ PG.constants.grep(/PQ_PIPELINE_/).find{|c| PG.const_get(c) == pipeline_status} }" if respond_to?(:pipeline_status) && pipeline_status != PG::PQ_PIPELINE_OFF
		stats << " client_encoding=#{ get_client_encoding }" if get_client_encoding != "UTF8"
		stats << " type_map_for_results=#{ type_map_for_results.to_s }" unless type_map_for_results.is_a?(PG::TypeMapAllStrings)
		stats << " type_map_for_queries=#{ type_map_for_queries.to_s }" unless type_map_for_queries.is_a?(PG::TypeMapAllStrings)
		stats << " encoder_for_put_copy_data=#{ encoder_for_put_copy_data.to_s }" if encoder_for_put_copy_data
		stats << " decoder_for_get_copy_data=#{ decoder_for_get_copy_data.to_s }" if decoder_for_get_copy_data
		" host=#{host} port=#{port} user=#{user}#{stats.join}"
	end
	return str
end

#internal_encodingEncoding

defined in Ruby 1.9 or later.

Returns:

  • an Encoding - client_encoding of the connection as a Ruby Encoding object.

  • nil - the client_encoding is ‘SQL_ASCII’

Returns:

  • (Encoding)


4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
# File 'ext/pg_connection.c', line 4060

static VALUE
pgconn_internal_encoding(VALUE self)
{
	PGconn *conn = pg_get_pgconn( self );
	rb_encoding *enc = pg_conn_enc_get( conn );

	if ( enc ) {
		return rb_enc_from_encoding( enc );
	} else {
		return Qnil;
	}
}

#internal_encoding=(value) ⇒ Object

A wrapper of #set_client_encoding. defined in Ruby 1.9 or later.

value can be one of:

  • an Encoding

  • a String - a name of Encoding

  • nil - sets the client_encoding to SQL_ASCII.



4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
# File 'ext/pg_connection.c', line 4087

static VALUE
pgconn_internal_encoding_set(VALUE self, VALUE enc)
{
	rb_check_frozen(self);
	if (NIL_P(enc)) {
		pgconn_sync_set_client_encoding( self, rb_usascii_str_new_cstr("SQL_ASCII") );
		return enc;
	}
	else if ( TYPE(enc) == T_STRING && strcasecmp("JOHAB", StringValueCStr(enc)) == 0 ) {
		pgconn_sync_set_client_encoding(self, rb_usascii_str_new_cstr("JOHAB"));
		return enc;
	}
	else {
		rb_encoding *rbenc = rb_to_encoding( enc );
		const char *name = pg_get_rb_encoding_as_pg_encoding( rbenc );

		if ( gvl_PQsetClientEncoding(pg_get_pgconn( self ), name) == -1 ) {
			VALUE server_encoding = pgconn_external_encoding( self );
			rb_raise( rb_eEncCompatError, "incompatible character encodings: %s and %s",
					  rb_enc_name(rb_to_encoding(server_encoding)), name );
		}
		pgconn_set_internal_encoding_index( self );
		return enc;
	}
}

#is_busyBoolean

Returns true if a command is busy, that is, if #get_result would block. Otherwise returns false.

Returns:

  • (Boolean)


2163
2164
2165
2166
2167
# File 'ext/pg_connection.c', line 2163

static VALUE
pgconn_is_busy(VALUE self)
{
	return gvl_PQisBusy(pg_get_pgconn(self)) ? Qtrue : Qfalse;
}

#isnonblockingObject Also known as: async_isnonblocking, nonblocking?

call-seq:

conn.isnonblocking() -> Boolean

Returns the blocking status of the database connection. Returns true if the connection is set to nonblocking mode and false if blocking.



471
472
473
# File 'lib/pg/connection.rb', line 471

def isnonblocking
	false
end

#lo_close(lo_desc) ⇒ nil Also known as: loclose

Closes the postgres large object of lo_desc.

Returns:

  • (nil)


3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
# File 'ext/pg_connection.c', line 3998

static VALUE
pgconn_loclose(VALUE self, VALUE in_lo_desc)
{
	PGconn *conn = pg_get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);
	int ret;

	BLOCKING_BEGIN(conn)
		ret = lo_close(conn,lo_desc);
	BLOCKING_END(conn)

	if(ret < 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_close failed");

	return Qnil;
}

#lo_creat([mode]) ⇒ Integer Also known as: locreat

Creates a large object with mode mode. Returns a large object Oid. On failure, it raises PG::Error.

Returns:

  • (Integer)


3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
# File 'ext/pg_connection.c', line 3715

static VALUE
pgconn_locreat(int argc, VALUE *argv, VALUE self)
{
	Oid lo_oid;
	int mode;
	VALUE nmode;
	PGconn *conn = pg_get_pgconn(self);

	if (rb_scan_args(argc, argv, "01", &nmode) == 0)
		mode = INV_READ;
	else
		mode = NUM2INT(nmode);

	BLOCKING_BEGIN(conn)
		lo_oid = lo_creat(conn, mode);
	BLOCKING_END(conn)

	if (lo_oid == 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_creat failed");

	return UINT2NUM(lo_oid);
}

#lo_create(oid) ⇒ Integer Also known as: locreate

Creates a large object with oid oid. Returns the large object Oid. On failure, it raises PG::Error.

Returns:

  • (Integer)


3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
# File 'ext/pg_connection.c', line 3745

static VALUE
pgconn_locreate(VALUE self, VALUE in_lo_oid)
{
	Oid ret, lo_oid;
	PGconn *conn = pg_get_pgconn(self);
	lo_oid = NUM2UINT(in_lo_oid);

	ret = lo_create(conn, lo_oid);
	if (ret == InvalidOid)
		pg_raise_conn_error( rb_ePGerror, self, "lo_create failed");

	return UINT2NUM(ret);
}

#lo_export(oid, file) ⇒ nil Also known as: loexport

Saves a large object of oid to a file.

Returns:

  • (nil)


3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
# File 'ext/pg_connection.c', line 3792

static VALUE
pgconn_loexport(VALUE self, VALUE lo_oid, VALUE filename)
{
	PGconn *conn = pg_get_pgconn(self);
	Oid oid;
	int ret;
	Check_Type(filename, T_STRING);

	oid = NUM2UINT(lo_oid);

	BLOCKING_BEGIN(conn)
		ret = lo_export(conn, oid, StringValueCStr(filename));
	BLOCKING_END(conn)

	if (ret < 0) {
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));
	}
	return Qnil;
}

#lo_import(file) ⇒ Integer Also known as: loimport

Import a file to a large object. Returns a large object Oid.

On failure, it raises a PG::Error.

Returns:

  • (Integer)


3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
# File 'ext/pg_connection.c', line 3767

static VALUE
pgconn_loimport(VALUE self, VALUE filename)
{
	Oid lo_oid;

	PGconn *conn = pg_get_pgconn(self);

	Check_Type(filename, T_STRING);

	BLOCKING_BEGIN(conn)
		lo_oid = lo_import(conn, StringValueCStr(filename));
	BLOCKING_END(conn)

	if (lo_oid == 0) {
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));
	}
	return UINT2NUM(lo_oid);
}

#lo_lseek(lo_desc, offset, whence) ⇒ Integer Also known as: lolseek, lo_seek, loseek

Move the large object pointer lo_desc to offset offset. Valid values for whence are SEEK_SET, SEEK_CUR, and SEEK_END. (Or 0, 1, or 2.)

Returns:

  • (Integer)


3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
# File 'ext/pg_connection.c', line 3927

static VALUE
pgconn_lolseek(VALUE self, VALUE in_lo_desc, VALUE offset, VALUE whence)
{
	PGconn *conn = pg_get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);
	int ret;

	BLOCKING_BEGIN(conn)
		ret = lo_lseek(conn, lo_desc, NUM2INT(offset), NUM2INT(whence));
	BLOCKING_END(conn)

	if(ret < 0) {
		pg_raise_conn_error( rb_ePGerror, self, "lo_lseek failed");
	}

	return INT2FIX(ret);
}

#lo_open(oid, [mode]) ⇒ Integer Also known as: loopen

Open a large object of oid. Returns a large object descriptor instance on success. The mode argument specifies the mode for the opened large object,which is either INV_READ, or INV_WRITE.

If mode is omitted, the default is INV_READ.

Returns:

  • (Integer)


3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
# File 'ext/pg_connection.c', line 3822

static VALUE
pgconn_loopen(int argc, VALUE *argv, VALUE self)
{
	Oid lo_oid;
	int fd, mode;
	VALUE nmode, selfid;
	PGconn *conn = pg_get_pgconn(self);

	rb_scan_args(argc, argv, "11", &selfid, &nmode);
	lo_oid = NUM2UINT(selfid);
	if(NIL_P(nmode))
		mode = INV_READ;
	else
		mode = NUM2INT(nmode);

	BLOCKING_BEGIN(conn)
		fd = lo_open(conn, lo_oid, mode);
	BLOCKING_END(conn)

	if(fd < 0) {
		pg_raise_conn_error( rb_ePGerror, self, "can't open large object: %s", PQerrorMessage(conn));
	}
	return INT2FIX(fd);
}

#lo_read(lo_desc, len) ⇒ String Also known as: loread

Attempts to read len bytes from large object lo_desc, returns resulting data.

Returns:

  • (String)


3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
# File 'ext/pg_connection.c', line 3885

static VALUE
pgconn_loread(VALUE self, VALUE in_lo_desc, VALUE in_len)
{
	int ret;
  PGconn *conn = pg_get_pgconn(self);
	int len = NUM2INT(in_len);
	int lo_desc = NUM2INT(in_lo_desc);
	VALUE str;
	char *buffer;

	if (len < 0)
		pg_raise_conn_error( rb_ePGerror, self, "negative length %d given", len);

	buffer = ALLOC_N(char, len);

	BLOCKING_BEGIN(conn)
		ret = lo_read(conn, lo_desc, buffer, len);
	BLOCKING_END(conn)

	if(ret < 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_read failed");

	if(ret == 0) {
		xfree(buffer);
		return Qnil;
	}

	str = rb_str_new(buffer, ret);
	xfree(buffer);

	return str;
}

#lo_tell(lo_desc) ⇒ Integer Also known as: lotell

Returns the current position of the large object lo_desc.

Returns:

  • (Integer)


3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
# File 'ext/pg_connection.c', line 3951

static VALUE
pgconn_lotell(VALUE self, VALUE in_lo_desc)
{
	int position;
	PGconn *conn = pg_get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);

	BLOCKING_BEGIN(conn)
		position = lo_tell(conn, lo_desc);
	BLOCKING_END(conn)

	if(position < 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_tell failed");

	return INT2FIX(position);
}

#lo_truncate(lo_desc, len) ⇒ nil Also known as: lotruncate

Truncates the large object lo_desc to size len.

Returns:

  • (nil)


3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
# File 'ext/pg_connection.c', line 3974

static VALUE
pgconn_lotruncate(VALUE self, VALUE in_lo_desc, VALUE in_len)
{
	PGconn *conn = pg_get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);
	size_t len = NUM2INT(in_len);
	int ret;

	BLOCKING_BEGIN(conn)
		ret = lo_truncate(conn,lo_desc,len);
	BLOCKING_END(conn)

	if(ret < 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_truncate failed");

	return Qnil;
}

Unlinks (deletes) the postgres large object of oid.

Returns:

  • (nil)


4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
# File 'ext/pg_connection.c', line 4021

static VALUE
pgconn_lounlink(VALUE self, VALUE in_oid)
{
	PGconn *conn = pg_get_pgconn(self);
	Oid oid = NUM2UINT(in_oid);
	int ret;

	BLOCKING_BEGIN(conn)
		ret = lo_unlink(conn,oid);
	BLOCKING_END(conn)

	if(ret < 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_unlink failed");

	return Qnil;
}

#lo_write(lo_desc, buffer) ⇒ Integer Also known as: lowrite

Writes the string buffer to the large object lo_desc. Returns the number of bytes written.

Returns:

  • (Integer)


3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
# File 'ext/pg_connection.c', line 3854

static VALUE
pgconn_lowrite(VALUE self, VALUE in_lo_desc, VALUE buffer)
{
	int n;
	PGconn *conn = pg_get_pgconn(self);
	int fd = NUM2INT(in_lo_desc);

	Check_Type(buffer, T_STRING);

	if( RSTRING_LEN(buffer) < 0) {
		pg_raise_conn_error( rb_ePGerror, self, "write buffer zero string");
	}
	BLOCKING_BEGIN(conn)
		n = lo_write(conn, fd, StringValuePtr(buffer),
				RSTRING_LEN(buffer));
	BLOCKING_END(conn)

	if(n < 0) {
		pg_raise_conn_error( rb_ePGerror, self, "lo_write failed: %s", PQerrorMessage(conn));
	}

	return INT2FIX(n);
}

#make_empty_pgresult(status) ⇒ PG::Result

Constructs and empty PG::Result with status status. status may be one of:

  • PGRES_EMPTY_QUERY

  • PGRES_COMMAND_OK

  • PGRES_TUPLES_OK

  • PGRES_COPY_OUT

  • PGRES_COPY_IN

  • PGRES_BAD_RESPONSE

  • PGRES_NONFATAL_ERROR

  • PGRES_FATAL_ERROR

  • PGRES_COPY_BOTH

  • PGRES_SINGLE_TUPLE

  • PGRES_PIPELINE_SYNC

  • PGRES_PIPELINE_ABORTED

Returns:



1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
# File 'ext/pg_connection.c', line 1593

static VALUE
pgconn_make_empty_pgresult(VALUE self, VALUE status)
{
	PGresult *result;
	VALUE rb_pgresult;
	PGconn *conn = pg_get_pgconn(self);
	result = PQmakeEmptyPGresult(conn, NUM2INT(status));
	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);
	return rb_pgresult;
}

#notifiesObject

Returns a hash of the unprocessed notifications. If there is no unprocessed notifier, it returns nil.



2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
# File 'ext/pg_connection.c', line 2236

static VALUE
pgconn_notifies(VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGnotify *notification;
	VALUE hash;
	VALUE sym_relname, sym_be_pid, sym_extra;
	VALUE relname, be_pid, extra;

	sym_relname = ID2SYM(rb_intern("relname"));
	sym_be_pid = ID2SYM(rb_intern("be_pid"));
	sym_extra = ID2SYM(rb_intern("extra"));

	notification = gvl_PQnotifies(this->pgconn);
	if (notification == NULL) {
		return Qnil;
	}

	hash = rb_hash_new();
	relname = rb_str_new2(notification->relname);
	be_pid = INT2NUM(notification->be_pid);
	extra = rb_str_new2(notification->extra);
	PG_ENCODING_SET_NOCHECK( relname, this->enc_idx );
	PG_ENCODING_SET_NOCHECK( extra, this->enc_idx );

	rb_hash_aset(hash, sym_relname, relname);
	rb_hash_aset(hash, sym_be_pid, be_pid);
	rb_hash_aset(hash, sym_extra, extra);

	PQfreemem(notification);
	return hash;
}

#optionsObject

Returns backend option string.



747
748
749
750
751
752
753
# File 'ext/pg_connection.c', line 747

static VALUE
pgconn_options(VALUE self)
{
	char *options = PQoptions(pg_get_pgconn(self));
	if (!options) return Qnil;
	return rb_str_new2(options);
}

#parameter_status(param_name) ⇒ String

Returns the setting of parameter param_name, where param_name is one of

  • server_version

  • server_encoding

  • client_encoding

  • is_superuser

  • session_authorization

  • DateStyle

  • TimeZone

  • integer_datetimes

  • standard_conforming_strings

Returns nil if the value of the parameter is not known.

Returns:

  • (String)


835
836
837
838
839
840
841
842
843
# File 'ext/pg_connection.c', line 835

static VALUE
pgconn_parameter_status(VALUE self, VALUE param_name)
{
	const char *ret = PQparameterStatus(pg_get_pgconn(self), StringValueCStr(param_name));
	if(ret == NULL)
		return Qnil;
	else
		return rb_str_new2(ret);
}

#passObject

Returns the authenticated password.



660
661
662
663
664
665
666
# File 'ext/pg_connection.c', line 660

static VALUE
pgconn_pass(VALUE self)
{
	char *user = PQpass(pg_get_pgconn(self));
	if (!user) return Qnil;
	return rb_str_new2(user);
}

#pipeline_statusInteger

Returns the current pipeline mode status of the libpq connection.

PQpipelineStatus can return one of the following values:

  • PQ_PIPELINE_ON - The libpq connection is in pipeline mode.

  • PQ_PIPELINE_OFF - The libpq connection is not in pipeline mode.

  • PQ_PIPELINE_ABORTED - The libpq connection is in pipeline mode and an error occurred while processing the current pipeline. The aborted flag is cleared when PQgetResult returns a result of type PGRES_PIPELINE_SYNC.

Available since PostgreSQL-14

Returns:

  • (Integer)


3596
3597
3598
3599
3600
3601
# File 'ext/pg_connection.c', line 3596

static VALUE
pgconn_pipeline_status(VALUE self)
{
	int res = PQpipelineStatus(pg_get_pgconn(self));
	return INT2FIX(res);
}

#pipeline_syncnil

Marks a synchronization point in a pipeline by sending a sync message and flushing the send buffer. This serves as the delimiter of an implicit transaction and an error recovery point; see Section 34.5.1.3 of the PostgreSQL documentation.

Raises PG::Error if the connection is not in pipeline mode or sending a sync message failed.

Available since PostgreSQL-14

Returns:

  • (nil)


3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
# File 'ext/pg_connection.c', line 3660

static VALUE
pgconn_pipeline_sync(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int res = PQpipelineSync(conn);
	if( res != 1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}

#portObject

Returns the connected server port number.



719
720
721
722
723
724
725
726
727
# File 'ext/pg_connection.c', line 719

static VALUE
pgconn_port(VALUE self)
{
	char* port = PQport(pg_get_pgconn(self));
	if (!port || port[0] == '\0')
		return INT2NUM(DEF_PGPORT);
	else
		return INT2NUM(atoi(port));
}

#prepare(stmt_name, sql[, param_types ]) ⇒ PG::Result Also known as: async_prepare

Prepares statement sql with name name to be executed later. Returns a PG::Result instance on success. On failure, it raises a PG::Error.

param_types is an optional parameter to specify the Oids of the types of the parameters.

If the types are not specified, they will be inferred by PostgreSQL. Instead of specifying type oids, it’s recommended to simply add explicit casts in the query to ensure that the right type is used.

For example: “SELECT $1::int”

PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query.

See also corresponding libpq function.

Returns:



3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
# File 'ext/pg_connection.c', line 3384

static VALUE
pgconn_async_prepare(int argc, VALUE *argv, VALUE self)
{
	VALUE rb_pgresult = Qnil;

	pgconn_discard_results( self );
	pgconn_send_prepare( argc, argv, self );
	rb_pgresult = pgconn_async_get_last_result( self );

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_pgresult, pg_result_clear, rb_pgresult );
	}
	return rb_pgresult;
}

#protocol_versionInteger

The 3.0 protocol will normally be used when communicating with PostgreSQL 7.4 or later servers; pre-7.4 servers support only protocol 2.0. (Protocol 1.0 is obsolete and not supported by libpq.)

Returns:

  • (Integer)


853
854
855
856
857
# File 'ext/pg_connection.c', line 853

static VALUE
pgconn_protocol_version(VALUE self)
{
	return INT2NUM(PQprotocolVersion(pg_get_pgconn(self)));
}

#put_copy_data(buffer, encoder = nil) ⇒ Object Also known as: async_put_copy_data

call-seq:

conn.put_copy_data( buffer [, encoder] ) -> Boolean

Transmits buffer as copy data to the server. Returns true if the data was sent, false if it was not sent (false is only possible if the connection is in nonblocking mode, and this command would block).

encoder can be a PG::Coder derivation (typically PG::TextEncoder::CopyRow). This encodes the data fields given as buffer from an Array of Strings to PostgreSQL’s COPY text format inclusive proper escaping. Optionally the encoder can type cast the fields from various Ruby types in one step, if PG::TextEncoder::CopyRow#type_map is set accordingly.

Raises an exception if an error occurs.

See also #copy_data.



495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
# File 'lib/pg/connection.rb', line 495

def put_copy_data(buffer, encoder=nil)
	# sync_put_copy_data does a non-blocking attept to flush data.
	until res=sync_put_copy_data(buffer, encoder)
		# It didn't flush immediately and allocation of more buffering memory failed.
		# Wait for all data sent by doing a blocking flush.
		res = flush
	end

	# And do a blocking flush every 100 calls.
	# This is to avoid memory bloat, when sending the data is slower than calls to put_copy_data happen.
	if (@calls_to_put_copy_data += 1) > 100
		@calls_to_put_copy_data = 0
		res = flush
	end
	res
end

#put_copy_end(*args) ⇒ Object Also known as: async_put_copy_end

call-seq:

conn.put_copy_end( [ error_message ] ) -> Boolean

Sends end-of-data indication to the server.

error_message is an optional parameter, and if set, forces the COPY command to fail with the string error_message.

Returns true if the end-of-data was sent, #false* if it was not sent (false is only possible if the connection is in nonblocking mode, and this command would block).



525
526
527
528
529
530
531
# File 'lib/pg/connection.rb', line 525

def put_copy_end(*args)
	until sync_put_copy_end(*args)
		flush
	end
	@calls_to_put_copy_data = 0
	flush
end

#quote_ident(str) ⇒ String #quote_ident(array) ⇒ String #PG::Connection.quote_ident(str) ⇒ String #PG::Connection.quote_ident(array) ⇒ String

Returns a string that is safe for inclusion in a SQL query as an identifier. Note: this is not a quote function for values, but for identifiers.

For example, in a typical SQL query: SELECT FOO FROM MYTABLE The identifier FOO is folded to lower case, so it actually means foo. If you really want to access the case-sensitive field name FOO, use this function like conn.quote_ident('FOO'), which will return "FOO" (with double-quotes). PostgreSQL will see the double-quotes, and it will not fold to lower case.

Similarly, this function also protects against special characters, and other things that might allow SQL injection if the identifier comes from an untrusted source.

If the parameter is an Array, then all it’s values are separately quoted and then joined by a “.” character. This can be used for identifiers in the form “schema”.“table”.“column” .

This method is functional identical to the encoder PG::TextEncoder::Identifier .

If the instance method form is used and the input string character encoding is different to the connection encoding, then the string is converted to this encoding, so that the returned string is always encoded as PG::Connection#internal_encoding .

In the singleton form (PG::Connection.quote_ident) the character encoding of the result string is set to the character encoding of the input string.

Overloads:

  • #quote_ident(str) ⇒ String

    Returns:

    • (String)
  • #quote_ident(array) ⇒ String

    Returns:

    • (String)
  • #PG::Connection.quote_ident(str) ⇒ String

    Returns:

    • (String)
  • #PG::Connection.quote_ident(array) ⇒ String

    Returns:

    • (String)


3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
# File 'ext/pg_connection.c', line 3006

static VALUE
pgconn_s_quote_ident(VALUE self, VALUE str_or_array)
{
	VALUE ret;
	int enc_idx;

	if( rb_obj_is_kind_of(self, rb_cPGconn) ){
		enc_idx = pg_get_connection(self)->enc_idx;
	}else{
		enc_idx = RB_TYPE_P(str_or_array, T_STRING) ? ENCODING_GET( str_or_array ) : rb_ascii8bit_encindex();
	}
	pg_text_enc_identifier(NULL, str_or_array, NULL, &ret, enc_idx);

	return ret;
}

#resetObject Also known as: async_reset

call-seq:

conn.reset()

Resets the backend connection. This method closes the backend connection and tries to re-connect.



567
568
569
570
571
572
573
574
575
576
# File 'lib/pg/connection.rb', line 567

def reset
	iopts = conninfo_hash.compact
	if iopts[:host] && !iopts[:host].empty? && PG.library_version >= 100000
		iopts = self.class.send(:resolve_hosts, iopts)
	end
	conninfo = self.class.parse_connect_args( iopts );
	reset_start2(conninfo)
	async_connect_or_reset(:reset_poll)
	self
end

#reset_pollInteger

Checks the status of a connection reset operation. See #connect_start and #connect_poll for usage information and return values.

Returns:

  • (Integer)


614
615
616
617
618
619
620
621
622
623
# File 'ext/pg_connection.c', line 614

static VALUE
pgconn_reset_poll(VALUE self)
{
	PostgresPollingStatusType status;
	status = gvl_PQresetPoll(pg_get_pgconn(self));

	pgconn_close_socket_io(self);

	return INT2FIX((int)status);
}

#reset_startnil

Initiate a connection reset in a nonblocking manner. This will close the current connection and attempt to reconnect using the same connection parameters. Use #reset_poll to check the status of the connection reset.

Returns:

  • (nil)


597
598
599
600
601
602
603
604
# File 'ext/pg_connection.c', line 597

static VALUE
pgconn_reset_start(VALUE self)
{
	pgconn_close_socket_io( self );
	if(gvl_PQresetStart(pg_get_pgconn(self)) == 0)
		pg_raise_conn_error( rb_eUnableToSend, self, "reset has failed");
	return Qnil;
}

#send_describe_portal(portal_name) ⇒ nil

Asynchronously send command to the server. Does not block. Use in combination with conn.get_result.

Returns:

  • (nil)


2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
# File 'ext/pg_connection.c', line 2104

static VALUE
pgconn_send_describe_portal(VALUE self, VALUE portal)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	/* returns 0 on failure */
	if(gvl_PQsendDescribePortal(this->pgconn, pg_cstr_enc(portal, this->enc_idx)) == 0)
		pg_raise_conn_error( rb_eUnableToSend, self, "%s", PQerrorMessage(this->pgconn));

	pgconn_wait_for_flush( self );
	return Qnil;
}

#send_describe_prepared(statement_name) ⇒ nil

Asynchronously send command to the server. Does not block. Use in combination with conn.get_result.

Returns:

  • (nil)


2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
# File 'ext/pg_connection.c', line 2084

static VALUE
pgconn_send_describe_prepared(VALUE self, VALUE stmt_name)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	/* returns 0 on failure */
	if(gvl_PQsendDescribePrepared(this->pgconn, pg_cstr_enc(stmt_name, this->enc_idx)) == 0)
		pg_raise_conn_error( rb_eUnableToSend, self, "%s", PQerrorMessage(this->pgconn));

	pgconn_wait_for_flush( self );
	return Qnil;
}

#pipeline_syncnil

Sends a request for the server to flush its output buffer.

The server flushes its output buffer automatically as a result of Connection#pipeline_sync being called, or on any request when not in pipeline mode. This function is useful to cause the server to flush its output buffer in pipeline mode without establishing a synchronization point. Note that the request is not itself flushed to the server automatically; use Connection#flush if necessary.

Available since PostgreSQL-14

Returns:

  • (nil)


3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
# File 'ext/pg_connection.c', line 3683

static VALUE
pgconn_send_flush_request(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int res = PQsendFlushRequest(conn);
	if( res != 1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}

#send_prepare(stmt_name, sql[, param_types ]) ⇒ nil

Prepares statement sql with name name to be executed later. Sends prepare command asynchronously, and returns immediately. On failure, it raises a PG::Error.

param_types is an optional parameter to specify the Oids of the types of the parameters.

If the types are not specified, they will be inferred by PostgreSQL. Instead of specifying type oids, it’s recommended to simply add explicit casts in the query to ensure that the right type is used.

For example: “SELECT $1::int”

PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query.

Returns:

  • (nil)


1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
# File 'ext/pg_connection.c', line 1970

static VALUE
pgconn_send_prepare(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	int result;
	VALUE name, command, in_paramtypes;
	VALUE param;
	int i = 0;
	int nParams = 0;
	Oid *paramTypes = NULL;
	const char *name_cstr;
	const char *command_cstr;
	int enc_idx = this->enc_idx;

	rb_scan_args(argc, argv, "21", &name, &command, &in_paramtypes);
	name_cstr = pg_cstr_enc(name, enc_idx);
	command_cstr = pg_cstr_enc(command, enc_idx);

	if(! NIL_P(in_paramtypes)) {
		Check_Type(in_paramtypes, T_ARRAY);
		nParams = (int)RARRAY_LEN(in_paramtypes);
		paramTypes = ALLOC_N(Oid, nParams);
		for(i = 0; i < nParams; i++) {
			param = rb_ary_entry(in_paramtypes, i);
			if(param == Qnil)
				paramTypes[i] = 0;
			else
				paramTypes[i] = NUM2UINT(param);
		}
	}
	result = gvl_PQsendPrepare(this->pgconn, name_cstr, command_cstr, nParams, paramTypes);

	xfree(paramTypes);

	if(result == 0) {
		pg_raise_conn_error( rb_eUnableToSend, self, "%s", PQerrorMessage(this->pgconn));
	}
	pgconn_wait_for_flush( self );
	return Qnil;
}

#send_query(sql) ⇒ nil

Sends SQL query request specified by sql to PostgreSQL for asynchronous processing, and immediately returns. On failure, it raises a PG::Error.

For backward compatibility, if you pass more than one parameter to this method, it will call #send_query_params for you. New code should explicitly use #send_query_params if argument placeholders are used.

Returns:

  • (nil)


1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
# File 'ext/pg_connection.c', line 1861

static VALUE
pgconn_send_query(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );

	/* If called with no or nil parameters, use PQexec for compatibility */
	if ( argc == 1 || (argc >= 2 && argc <= 4 && NIL_P(argv[1]) )) {
		if(gvl_PQsendQuery(this->pgconn, pg_cstr_enc(argv[0], this->enc_idx)) == 0)
			pg_raise_conn_error( rb_eUnableToSend, self, "%s", PQerrorMessage(this->pgconn));

		pgconn_wait_for_flush( self );
		return Qnil;
	}

	pg_deprecated(2, ("forwarding async_exec to async_exec_params and send_query to send_query_params is deprecated"));

	/* If called with parameters, and optionally result_format,
	 * use PQsendQueryParams
	 */
	return pgconn_send_query_params( argc, argv, self);
}

#send_query_params(sql, params[, result_format [, type_map ]]) ⇒ nil

Sends SQL query request specified by sql to PostgreSQL for asynchronous processing, and immediately returns. On failure, it raises a PG::Error.

params is an array of the bind parameters for the SQL query. Each element of the params array may be either:

a hash of the form:
  {:value  => String (value of bind parameter)
   :type   => Integer (oid of type of bind parameter)
   :format => Integer (0 for text, 1 for binary)
  }
or, it may be a String. If it is a string, that is equivalent to the hash:
  { :value => <string value>, :type => 0, :format => 0 }

PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query. The 0th element of the params array is bound to $1, the 1st element is bound to $2, etc. nil is treated as NULL.

If the types are not specified, they will be inferred by PostgreSQL. Instead of specifying type oids, it’s recommended to simply add explicit casts in the query to ensure that the right type is used.

For example: “SELECT $1::int”

The optional result_format should be 0 for text results, 1 for binary.

type_map can be a PG::TypeMap derivation (such as PG::BasicTypeMapForQueries). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.

Returns:

  • (nil)


1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
# File 'ext/pg_connection.c', line 1921

static VALUE
pgconn_send_query_params(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	int result;
	VALUE command, in_res_fmt;
	int nParams;
	int resultFormat;
	struct query_params_data paramsData = { this->enc_idx };

	rb_scan_args(argc, argv, "22", &command, &paramsData.params, &in_res_fmt, &paramsData.typemap);
	paramsData.with_types = 1;

	pgconn_query_assign_typemap( self, &paramsData );
	resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt);
	nParams = alloc_query_params( &paramsData );

	result = gvl_PQsendQueryParams(this->pgconn, pg_cstr_enc(command, paramsData.enc_idx), nParams, paramsData.types,
		(const char * const *)paramsData.values, paramsData.lengths, paramsData.formats, resultFormat);

	free_query_params( &paramsData );

	if(result == 0)
		pg_raise_conn_error( rb_eUnableToSend, self, "%s", PQerrorMessage(this->pgconn));

	pgconn_wait_for_flush( self );
	return Qnil;
}

#send_query_prepared(statement_name[, params, result_format[, type_map ]]) ⇒ Object #-Object

Execute prepared named statement specified by statement_name asynchronously, and returns immediately. On failure, it raises a PG::Error.

params is an array of the optional bind parameters for the SQL query. Each element of the params array may be either:

a hash of the form:
  {:value  => String (value of bind parameter)
   :format => Integer (0 for text, 1 for binary)
  }
or, it may be a String. If it is a string, that is equivalent to the hash:
  { :value => <string value>, :format => 0 }

PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query. The 0th element of the params array is bound to $1, the 1st element is bound to $2, etc. nil is treated as NULL.

The optional result_format should be 0 for text results, 1 for binary.

type_map can be a PG::TypeMap derivation (such as PG::BasicTypeMapForQueries). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.



2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
# File 'ext/pg_connection.c', line 2043

static VALUE
pgconn_send_query_prepared(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	int result;
	VALUE name, in_res_fmt;
	int nParams;
	int resultFormat;
	struct query_params_data paramsData = { this->enc_idx };

	rb_scan_args(argc, argv, "13", &name, &paramsData.params, &in_res_fmt, &paramsData.typemap);
	paramsData.with_types = 0;

	if(NIL_P(paramsData.params)) {
		paramsData.params = rb_ary_new2(0);
	}
	pgconn_query_assign_typemap( self, &paramsData );

	resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt);
	nParams = alloc_query_params( &paramsData );

	result = gvl_PQsendQueryPrepared(this->pgconn, pg_cstr_enc(name, paramsData.enc_idx), nParams,
		(const char * const *)paramsData.values, paramsData.lengths, paramsData.formats,
		resultFormat);

	free_query_params( &paramsData );

	if(result == 0)
		pg_raise_conn_error( rb_eUnableToSend, self, "%s", PQerrorMessage(this->pgconn));

	pgconn_wait_for_flush( self );
	return Qnil;
}

#server_versionInteger

The number is formed by converting the major, minor, and revision numbers into two-decimal-digit numbers and appending them together. For example, version 7.4.2 will be returned as 70402, and version 8.1 will be returned as 80100 (leading zeroes are not shown). Zero is returned if the connection is bad.

Returns:

  • (Integer)


870
871
872
873
874
# File 'ext/pg_connection.c', line 870

static VALUE
pgconn_server_version(VALUE self)
{
	return INT2NUM(PQserverVersion(pg_get_pgconn(self)));
}

#set_client_encoding(encoding) ⇒ Object Also known as: async_set_client_encoding, client_encoding=

Sets the client encoding to the encoding String.



4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
# File 'ext/pg_connection.c', line 4140

static VALUE
pgconn_async_set_client_encoding(VALUE self, VALUE encname)
{
	VALUE query_format, query;

	rb_check_frozen(self);
	Check_Type(encname, T_STRING);
	query_format = rb_str_new_cstr("set client_encoding to '%s'");
	query = rb_funcall(query_format, rb_intern("%"), 1, encname);

	pgconn_async_exec(1, &query, self);
	pgconn_set_internal_encoding_index( self );

	return Qnil;
}

#set_default_encodingEncoding

If Ruby has its Encoding.default_internal set, set PostgreSQL’s client_encoding to match. Returns the new Encoding, or nil if the default internal encoding wasn’t set.

Returns:

  • (Encoding)


4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
# File 'ext/pg_connection.c', line 4191

static VALUE
pgconn_set_default_encoding( VALUE self )
{
	PGconn *conn = pg_get_pgconn( self );
	rb_encoding *rb_enc;

	rb_check_frozen(self);
	if (( rb_enc = rb_default_internal_encoding() )) {
		rb_encoding * conn_encoding = pg_conn_enc_get( conn );

		/* Don't set the server encoding, if it's unnecessary.
		 * This is important for connection proxies, who disallow configuration settings.
		 */
		if ( conn_encoding != rb_enc ) {
			const char *encname = pg_get_rb_encoding_as_pg_encoding( rb_enc );
			if ( pgconn_set_client_encoding_async(self, rb_str_new_cstr(encname)) != 0 )
				rb_warning( "Failed to set the default_internal encoding to %s: '%s'",
								encname, PQerrorMessage(conn) );
		}
		pgconn_set_internal_encoding_index( self );
		return rb_enc_from_encoding( rb_enc );
	} else {
		pgconn_set_internal_encoding_index( self );
		return Qnil;
	}
}

#set_error_context_visibility(context_visibility) ⇒ Integer

Sets connection’s context display mode to context_visibility and returns the previous setting. Available settings are:

  • PQSHOW_CONTEXT_NEVER

  • PQSHOW_CONTEXT_ERRORS

  • PQSHOW_CONTEXT_ALWAYS

This mode controls whether the CONTEXT field is included in messages (unless the verbosity setting is TERSE, in which case CONTEXT is never shown). The NEVER mode never includes CONTEXT, while ALWAYS always includes it if available. In ERRORS mode (the default), CONTEXT fields are included only for error messages, not for notices and warnings.

Changing this mode does not affect the messages available from already-existing PG::Result objects, only subsequently-created ones. (But see PG::Result#verbose_error_message if you want to print a previous error with a different display mode.)

See also corresponding libpq function.

Available since PostgreSQL-9.6

Returns:

  • (Integer)


2719
2720
2721
2722
2723
2724
2725
# File 'ext/pg_connection.c', line 2719

static VALUE
pgconn_set_error_context_visibility(VALUE self, VALUE in_context_visibility)
{
	PGconn *conn = pg_get_pgconn(self);
	PGContextVisibility context_visibility = NUM2INT(in_context_visibility);
	return INT2FIX(PQsetErrorContextVisibility(conn, context_visibility));
}

#set_error_verbosity(verbosity) ⇒ Integer

Sets connection’s verbosity to verbosity and returns the previous setting. Available settings are:

  • PQERRORS_TERSE

  • PQERRORS_DEFAULT

  • PQERRORS_VERBOSE

  • PQERRORS_SQLSTATE

Changing the verbosity does not affect the messages available from already-existing PG::Result objects, only subsequently-created ones. (But see PG::Result#verbose_error_message if you want to print a previous error with a different verbosity.)

See also corresponding libpq function.

Returns:

  • (Integer)


2689
2690
2691
2692
2693
2694
2695
# File 'ext/pg_connection.c', line 2689

static VALUE
pgconn_set_error_verbosity(VALUE self, VALUE in_verbosity)
{
	PGconn *conn = pg_get_pgconn(self);
	PGVerbosity verbosity = NUM2INT(in_verbosity);
	return INT2FIX(PQsetErrorVerbosity(conn, verbosity));
}

#set_notice_processor {|message| ... } ⇒ Proc

See #set_notice_receiver for the description of what this and the notice_processor methods do.

This function takes a new block to act as the notice processor and returns the Proc object previously set, or nil if it was previously the default. The block should accept a single String object.

If you pass no arguments, it will reset the handler to the default.

Yields:

  • (message)

Returns:

  • (Proc)


2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
# File 'ext/pg_connection.c', line 2901

static VALUE
pgconn_set_notice_processor(VALUE self)
{
	VALUE proc, old_proc;
	t_pg_connection *this = pg_get_connection_safe( self );

	rb_check_frozen(self);
	/* If default_notice_processor is unset, assume that the current
	 * notice processor is the default, and save it to a global variable.
	 * This should not be a problem because the default processor is
	 * always the same, so won't vary among connections.
	 */
	if(this->default_notice_processor == NULL)
		this->default_notice_processor = PQsetNoticeProcessor(this->pgconn, NULL, NULL);

	old_proc = this->notice_processor;
	if( rb_block_given_p() ) {
		proc = rb_block_proc();
		PQsetNoticeProcessor(this->pgconn, gvl_notice_processor_proxy, (void *)self);
	} else {
		/* if no block is given, set back to default */
		proc = Qnil;
		PQsetNoticeProcessor(this->pgconn, this->default_notice_processor, NULL);
	}

	RB_OBJ_WRITE(self, &this->notice_processor, proc);
	return old_proc;
}

#set_notice_receiver {|result| ... } ⇒ Proc

Notice and warning messages generated by the server are not returned by the query execution functions, since they do not imply failure of the query. Instead they are passed to a notice handling function, and execution continues normally after the handler returns. The default notice handling function prints the message on stderr, but the application can override this behavior by supplying its own handling function.

For historical reasons, there are two levels of notice handling, called the notice receiver and notice processor. The default behavior is for the notice receiver to format the notice and pass a string to the notice processor for printing. However, an application that chooses to provide its own notice receiver will typically ignore the notice processor layer and just do all the work in the notice receiver.

This function takes a new block to act as the handler, which should accept a single parameter that will be a PG::Result object, and returns the Proc object previously set, or nil if it was previously the default.

If you pass no arguments, it will reset the handler to the default.

Note: The result passed to the block should not be used outside of the block, since the corresponding C object could be freed after the block finishes.

Yields:

  • (result)

Returns:

  • (Proc)


2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
# File 'ext/pg_connection.c', line 2840

static VALUE
pgconn_set_notice_receiver(VALUE self)
{
	VALUE proc, old_proc;
	t_pg_connection *this = pg_get_connection_safe( self );

	rb_check_frozen(self);
	/* If default_notice_receiver is unset, assume that the current
	 * notice receiver is the default, and save it to a global variable.
	 * This should not be a problem because the default receiver is
	 * always the same, so won't vary among connections.
	 */
	if(this->default_notice_receiver == NULL)
		this->default_notice_receiver = PQsetNoticeReceiver(this->pgconn, NULL, NULL);

	old_proc = this->notice_receiver;
	if( rb_block_given_p() ) {
		proc = rb_block_proc();
		PQsetNoticeReceiver(this->pgconn, gvl_notice_receiver_proxy, (void *)self);
	} else {
		/* if no block is given, set back to default */
		proc = Qnil;
		PQsetNoticeReceiver(this->pgconn, this->default_notice_receiver, NULL);
	}

	RB_OBJ_WRITE(self, &this->notice_receiver, proc);
	return old_proc;
}

#set_single_row_modeself

To enter single-row mode, call this method immediately after a successful call of send_query (or a sibling function). This mode selection is effective only for the currently executing query. Then call Connection#get_result repeatedly, until it returns nil.

Each (but the last) received Result has exactly one row and a Result#result_status of PGRES_SINGLE_TUPLE. The last Result has zero rows and is used to indicate a successful execution of the query. All of these Result objects will contain the same row description data (column names, types, etc) that an ordinary Result object for the query would have.

Caution: While processing a query, the server may return some rows and then encounter an error, causing the query to be aborted. Ordinarily, pg discards any such rows and reports only the error. But in single-row mode, those rows will have already been returned to the application. Hence, the application will see some Result objects followed by an Error raised in get_result. For proper transactional behavior, the application must be designed to discard or undo whatever has been done with the previously-processed rows, if the query ultimately fails.

Example:

conn.send_query( "your SQL command" )
conn.set_single_row_mode
loop do
  res = conn.get_result or break
  res.check
  res.each do |row|
    # do something with the received row
  end
end

Returns:

  • (self)


1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
# File 'ext/pg_connection.c', line 1834

static VALUE
pgconn_set_single_row_mode(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);

	rb_check_frozen(self);
	if( PQsetSingleRowMode(conn) == 0 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return self;
}

#setnonblocking(enabled) ⇒ Object Also known as: async_setnonblocking

call-seq:

conn.setnonblocking(Boolean) -> nil

Sets the nonblocking status of the connection. In the blocking state, calls to #send_query will block until the message is sent to the server, but will not wait for the query results. In the nonblocking state, calls to #send_query will return an error if the socket is not ready for writing. Note: This function does not affect #exec, because that function doesn’t return until the server has processed the query and returned the results.

Returns nil.



457
458
459
460
461
# File 'lib/pg/connection.rb', line 457

def setnonblocking(enabled)
	singleton_class.async_send_api = !enabled
	self.flush_data = !enabled
	sync_setnonblocking(true)
end

#socketInteger

This method is deprecated. Please use the more portable method #socket_io .

Returns the socket’s file descriptor for this connection. IO.for_fd() can be used to build a proper IO object to the socket. If you do so, you will likely also want to set autoclose=false on it to prevent Ruby from closing the socket to PostgreSQL if it goes out of scope. Alternatively, you can use #socket_io, which creates an IO that’s associated with the connection object itself, and so won’t go out of scope until the connection does.

Note: On Windows the file descriptor is not usable, since it can not be used to build a Ruby IO object.

Returns:

  • (Integer)


910
911
912
913
914
915
916
917
918
919
920
# File 'ext/pg_connection.c', line 910

static VALUE
pgconn_socket(VALUE self)
{
	int sd;
	pg_deprecated(4, ("conn.socket is deprecated and should be replaced by conn.socket_io"));

	if( (sd = PQsocket(pg_get_pgconn(self))) < 0)
		pg_raise_conn_error( rb_eConnectionBad, self, "PQsocket() can't get socket descriptor");

	return INT2NUM(sd);
}

#socket_ioObject

Fetch an IO object created from the Connection’s underlying socket. This object can be used per socket_io.wait_readable, socket_io.wait_writable or for IO.select to wait for events while running asynchronous API calls. IO#wait_*able is is Fiber.scheduler compatible in contrast to IO.select.

The IO object can change while the connection is established, but is memorized afterwards. So be sure not to cache the IO object, but repeat calling conn.socket_io instead.

Using this method also works on Windows in contrast to using #socket . It also avoids the problem of the underlying connection being closed by Ruby when an IO created using IO.for_fd(conn.socket) goes out of scope.



936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
# File 'ext/pg_connection.c', line 936

static VALUE
pgconn_socket_io(VALUE self)
{
	int sd;
	int ruby_sd;
	t_pg_connection *this = pg_get_connection_safe( self );
	VALUE cSocket;
	VALUE socket_io = this->socket_io;

	if ( !RTEST(socket_io) ) {
		if( (sd = PQsocket(this->pgconn)) < 0){
			pg_raise_conn_error( rb_eConnectionBad, self, "PQsocket() can't get socket descriptor");
		}

		#ifdef _WIN32
			ruby_sd = rb_w32_wrap_io_handle((HANDLE)(intptr_t)sd, O_RDWR|O_BINARY|O_NOINHERIT);
			if( ruby_sd == -1 )
				pg_raise_conn_error( rb_eConnectionBad, self, "Could not wrap win32 socket handle");

			this->ruby_sd = ruby_sd;
		#else
			ruby_sd = sd;
		#endif

		cSocket = rb_const_get(rb_cObject, rb_intern("BasicSocket"));
		socket_io = rb_funcall( cSocket, rb_intern("for_fd"), 1, INT2NUM(ruby_sd));

		/* Disable autoclose feature */
		rb_funcall( socket_io, s_id_autoclose_set, 1, Qfalse );

		RB_OBJ_WRITE(self, &this->socket_io, socket_io);
	}

	return socket_io;
}

#ssl_attribute(attribute_name) ⇒ String

Returns SSL-related information about the connection.

The list of available attributes varies depending on the SSL library being used, and the type of connection. If an attribute is not available, returns nil.

The following attributes are commonly available:

library

Name of the SSL implementation in use. (Currently, only “OpenSSL” is implemented)

protocol

SSL/TLS version in use. Common values are “SSLv2”, “SSLv3”, “TLSv1”, “TLSv1.1” and “TLSv1.2”, but an implementation may return other strings if some other protocol is used.

key_bits

Number of key bits used by the encryption algorithm.

cipher

A short name of the ciphersuite used, e.g. “DHE-RSA-DES-CBC3-SHA”. The names are specific to each SSL implementation.

compression

If SSL compression is in use, returns the name of the compression algorithm, or “on” if compression is used but the algorithm is not known. If compression is not in use, returns “off”.

See also #ssl_attribute_names and the corresponding libpq function.

Available since PostgreSQL-9.5

Returns:

  • (String)


3544
3545
3546
3547
3548
3549
3550
3551
# File 'ext/pg_connection.c', line 3544

static VALUE
pgconn_ssl_attribute(VALUE self, VALUE attribute_name)
{
	const char *p_attr;

	p_attr = PQsslAttribute(pg_get_pgconn(self), StringValueCStr(attribute_name));
	return p_attr ? rb_str_new_cstr(p_attr) : Qnil;
}

#ssl_attribute_namesArray<String>

Return an array of SSL attribute names available.

See also #ssl_attribute

Available since PostgreSQL-9.5

Returns:

  • (Array<String>)


3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
# File 'ext/pg_connection.c', line 3563

static VALUE
pgconn_ssl_attribute_names(VALUE self)
{
	int i;
	const char * const * p_list = PQsslAttributeNames(pg_get_pgconn(self));
	VALUE ary = rb_ary_new();

	for ( i = 0; p_list[i]; i++ ) {
		rb_ary_push( ary, rb_str_new_cstr( p_list[i] ));
	}
	return ary;
}

#ssl_attributesObject

call-seq:

conn.ssl_attributes -> Hash<String,String>

Returns SSL-related information about the connection as key/value pairs

The available attributes varies depending on the SSL library being used, and the type of connection.

See also #ssl_attribute



362
363
364
365
366
# File 'lib/pg/connection.rb', line 362

def ssl_attributes
	ssl_attribute_names.each.with_object({}) do |n,h|
		h[n] = ssl_attribute(n)
	end
end

#ssl_in_use?Boolean

Returns true if the connection uses SSL/TLS, false if not.

Available since PostgreSQL-9.5

Returns:

  • (Boolean)


3510
3511
3512
3513
3514
# File 'ext/pg_connection.c', line 3510

static VALUE
pgconn_ssl_in_use(VALUE self)
{
	return PQsslInUse(pg_get_pgconn(self)) ? Qtrue : Qfalse;
}

#statusObject

Returns the status of the connection, which is one:

PG::Constants::CONNECTION_OK
PG::Constants::CONNECTION_BAD

… and other constants of kind PG::Constants::CONNECTION_*

This method returns the status of the last command from memory. It doesn’t do any socket access hence is not suitable to test the connectivity. See check_socket for a way to verify the socket state.

Example:

PG.constants.grep(/CONNECTION_/).find{|c| PG.const_get(c) == conn.status} # => :CONNECTION_OK


794
795
796
797
798
# File 'ext/pg_connection.c', line 794

static VALUE
pgconn_status(VALUE self)
{
	return INT2NUM(PQstatus(pg_get_pgconn(self)));
}

#sync_cancelObject

**** PG::Connection INSTANCE METHODS: Cancelling Queries in Progress *****



2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
# File 'ext/pg_connection.c', line 2206

static VALUE
pgconn_sync_cancel(VALUE self)
{
	char errbuf[256];
	PGcancel *cancel;
	VALUE retval;
	int ret;

	cancel = PQgetCancel(pg_get_pgconn(self));
	if(cancel == NULL)
		pg_raise_conn_error( rb_ePGerror, self, "Invalid connection!");

	ret = gvl_PQcancel(cancel, errbuf, sizeof(errbuf));
	if(ret == 1)
		retval = Qnil;
	else
		retval = rb_str_new2(errbuf);

	PQfreeCancel(cancel);
	return retval;
}

#sync_describe_portal(portal_name) ⇒ PG::Result

This function has the same behavior as #async_describe_portal, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #describe_portal instead, unless you have a good reason to do so.

Returns:



1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
# File 'ext/pg_connection.c', line 1554

static VALUE
pgconn_sync_describe_portal(VALUE self, VALUE stmt_name)
{
	PGresult *result;
	VALUE rb_pgresult;
	t_pg_connection *this = pg_get_connection_safe( self );
	const char *stmt;
	if(NIL_P(stmt_name)) {
		stmt = NULL;
	}
	else {
		stmt = pg_cstr_enc(stmt_name, this->enc_idx);
	}
	result = gvl_PQdescribePortal(this->pgconn, stmt);
	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);
	return rb_pgresult;
}

#sync_describe_prepared(statement_name) ⇒ PG::Result

This function has the same behavior as #async_describe_prepared, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #describe_prepared instead, unless you have a good reason to do so.

Returns:



1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
# File 'ext/pg_connection.c', line 1526

static VALUE
pgconn_sync_describe_prepared(VALUE self, VALUE stmt_name)
{
	PGresult *result;
	VALUE rb_pgresult;
	t_pg_connection *this = pg_get_connection_safe( self );
	const char *stmt;
	if(NIL_P(stmt_name)) {
		stmt = NULL;
	}
	else {
		stmt = pg_cstr_enc(stmt_name, this->enc_idx);
	}
	result = gvl_PQdescribePrepared(this->pgconn, stmt);
	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);
	return rb_pgresult;
}

#sync_encrypt_password(*args) ⇒ Object



422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
# File 'ext/pg_connection.c', line 422

static VALUE
pgconn_sync_encrypt_password(int argc, VALUE *argv, VALUE self)
{
	char *encrypted = NULL;
	VALUE rval = Qnil;
	VALUE password, username, algorithm;
	PGconn *conn = pg_get_pgconn(self);

	rb_scan_args( argc, argv, "21", &password, &username, &algorithm );

	Check_Type(password, T_STRING);
	Check_Type(username, T_STRING);

	encrypted = gvl_PQencryptPasswordConn(conn, StringValueCStr(password), StringValueCStr(username), RTEST(algorithm) ? StringValueCStr(algorithm) : NULL);
	if ( encrypted ) {
		rval = rb_str_new2( encrypted );
		PQfreemem( encrypted );
	} else {
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));
	}

	return rval;
}

#sync_exec(sql) ⇒ PG::Result #sync_exec(sql) {|pg_result| ... } ⇒ Object

This function has the same behavior as #async_exec, but is implemented using the synchronous command processing API of libpq. It’s not recommended to use explicit sync or async variants but #exec instead, unless you have a good reason to do so.

Both #sync_exec and #async_exec release the GVL while waiting for server response, so that concurrent threads will get executed. However #async_exec has two advantages:

  1. #async_exec can be aborted by signals (like Ctrl-C), while #exec blocks signal processing until the query is answered.

  2. Ruby VM gets notified about IO blocked operations and can pass them through Fiber.scheduler. So only async_* methods are compatible to event based schedulers like the async gem.

Overloads:

  • #sync_exec(sql) ⇒ PG::Result

    Returns:

  • #sync_exec(sql) {|pg_result| ... } ⇒ Object

    Yields:

    • (pg_result)


1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
# File 'ext/pg_connection.c', line 1078

static VALUE
pgconn_sync_exec(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGresult *result = NULL;
	VALUE rb_pgresult;

	/* If called with no or nil parameters, use PQexec for compatibility */
	if ( argc == 1 || (argc >= 2 && argc <= 4 && NIL_P(argv[1]) )) {
		VALUE query_str = argv[0];

		result = gvl_PQexec(this->pgconn, pg_cstr_enc(query_str, this->enc_idx));
		rb_pgresult = pg_new_result(result, self);
		pg_result_check(rb_pgresult);
		if (rb_block_given_p()) {
			return rb_ensure(rb_yield, rb_pgresult, pg_result_clear, rb_pgresult);
		}
		return rb_pgresult;
	}
	pg_deprecated(0, ("forwarding exec to exec_params is deprecated"));

	/* Otherwise, just call #exec_params instead for backward-compatibility */
	return pgconn_sync_exec_params( argc, argv, self );

}

#sync_exec_params(sql, params[, result_format[, type_map]]) ⇒ PG::Result #sync_exec_params(sql, params[, result_format[, type_map]]) {|pg_result| ... } ⇒ Object

This function has the same behavior as #async_exec_params, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #exec_params instead, unless you have a good reason to do so.

Overloads:

  • #sync_exec_params(sql, params[, result_format[, type_map]]) ⇒ PG::Result

    Returns:

  • #sync_exec_params(sql, params[, result_format[, type_map]]) {|pg_result| ... } ⇒ Object

    Yields:

    • (pg_result)


1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
# File 'ext/pg_connection.c', line 1381

static VALUE
pgconn_sync_exec_params( int argc, VALUE *argv, VALUE self )
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE command, in_res_fmt;
	int nParams;
	int resultFormat;
	struct query_params_data paramsData = { this->enc_idx };

	/* For compatibility we accept 1 to 4 parameters */
	rb_scan_args(argc, argv, "13", &command, &paramsData.params, &in_res_fmt, &paramsData.typemap);
	paramsData.with_types = 1;

	/*
	 * For backward compatibility no or +nil+ for the second parameter
	 * is passed to #exec
	 */
	if ( NIL_P(paramsData.params) ) {
		pg_deprecated(1, ("forwarding exec_params to exec is deprecated"));
		return pgconn_sync_exec( 1, argv, self );
	}
	pgconn_query_assign_typemap( self, &paramsData );

	resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt);
	nParams = alloc_query_params( &paramsData );

	result = gvl_PQexecParams(this->pgconn, pg_cstr_enc(command, paramsData.enc_idx), nParams, paramsData.types,
		(const char * const *)paramsData.values, paramsData.lengths, paramsData.formats, resultFormat);

	free_query_params( &paramsData );

	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);

	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, rb_pgresult, pg_result_clear, rb_pgresult);
	}

	return rb_pgresult;
}

#sync_exec_prepared(statement_name[, params, result_format[, type_map]]) ⇒ PG::Result #sync_exec_prepared(statement_name[, params, result_format[, type_map]]) {|pg_result| ... } ⇒ Object

This function has the same behavior as #async_exec_prepared, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #exec_prepared instead, unless you have a good reason to do so.

Overloads:

  • #sync_exec_prepared(statement_name[, params, result_format[, type_map]]) ⇒ PG::Result

    Returns:

  • #sync_exec_prepared(statement_name[, params, result_format[, type_map]]) {|pg_result| ... } ⇒ Object

    Yields:

    • (pg_result)


1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
# File 'ext/pg_connection.c', line 1481

static VALUE
pgconn_sync_exec_prepared(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE name, in_res_fmt;
	int nParams;
	int resultFormat;
	struct query_params_data paramsData = { this->enc_idx };

	rb_scan_args(argc, argv, "13", &name, &paramsData.params, &in_res_fmt, &paramsData.typemap);
	paramsData.with_types = 0;

	if(NIL_P(paramsData.params)) {
		paramsData.params = rb_ary_new2(0);
	}
	pgconn_query_assign_typemap( self, &paramsData );

	resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt);
	nParams = alloc_query_params( &paramsData );

	result = gvl_PQexecPrepared(this->pgconn, pg_cstr_enc(name, paramsData.enc_idx), nParams,
		(const char * const *)paramsData.values, paramsData.lengths, paramsData.formats,
		resultFormat);

	free_query_params( &paramsData );

	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);
	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, rb_pgresult,
			pg_result_clear, rb_pgresult);
	}
	return rb_pgresult;
}

#sync_flushObject



2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
# File 'ext/pg_connection.c', line 2195

static VALUE
pgconn_sync_flush(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int ret = PQflush(conn);
	if(ret == -1)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return (ret) ? Qfalse : Qtrue;
}

#sync_get_copy_data(*args) ⇒ Object



2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
# File 'ext/pg_connection.c', line 2628

static VALUE
pgconn_sync_get_copy_data(int argc, VALUE *argv, VALUE self )
{
	VALUE async_in;
	VALUE result;
	int ret;
	char *buffer;
	VALUE decoder;
	t_pg_coder *p_coder = NULL;
	t_pg_connection *this = pg_get_connection_safe( self );

	rb_scan_args(argc, argv, "02", &async_in, &decoder);

	if( NIL_P(decoder) ){
		if( !NIL_P(this->decoder_for_get_copy_data) ){
			p_coder = RTYPEDDATA_DATA( this->decoder_for_get_copy_data );
		}
	} else {
		/* Check argument type and use argument decoder */
		TypedData_Get_Struct(decoder, t_pg_coder, &pg_coder_type, p_coder);
	}

	ret = gvl_PQgetCopyData(this->pgconn, &buffer, RTEST(async_in));
	if(ret == -2){ /* error */
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(this->pgconn));
	}
	if(ret == -1) { /* No data left */
		return Qnil;
	}
	if(ret == 0) { /* would block */
		return Qfalse;
	}

	if( p_coder ){
		t_pg_coder_dec_func dec_func = pg_coder_dec_func( p_coder, p_coder->format );
		result =  dec_func( p_coder, buffer, ret, 0, 0, this->enc_idx );
	} else {
		result = rb_str_new(buffer, ret);
	}

	PQfreemem(buffer);
	return result;
}

#sync_get_last_resultPG::Result

This function has the same behavior as #async_get_last_result, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #get_last_result instead, unless you have a good reason to do so.

Returns:



3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
# File 'ext/pg_connection.c', line 3075

static VALUE
pgconn_sync_get_last_result(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	VALUE rb_pgresult = Qnil;
	PGresult *cur, *prev;


	cur = prev = NULL;
	while ((cur = gvl_PQgetResult(conn)) != NULL) {
		int status;

		if (prev) PQclear(prev);
		prev = cur;

		status = PQresultStatus(cur);
		if (status == PGRES_COPY_OUT || status == PGRES_COPY_IN || status == PGRES_COPY_BOTH)
			break;
	}

	if (prev) {
		rb_pgresult = pg_new_result( prev, self );
		pg_result_check(rb_pgresult);
	}

	return rb_pgresult;
}

#sync_get_resultObject



2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
# File 'ext/pg_connection.c', line 2117

static VALUE
pgconn_sync_get_result(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	PGresult *result;
	VALUE rb_pgresult;

	result = gvl_PQgetResult(conn);
	if(result == NULL)
		return Qnil;
	rb_pgresult = pg_new_result(result, self);
	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, rb_pgresult,
			pg_result_clear, rb_pgresult);
	}
	return rb_pgresult;
}

#sync_isnonblockingObject



2189
2190
2191
2192
2193
# File 'ext/pg_connection.c', line 2189

static VALUE
pgconn_sync_isnonblocking(VALUE self)
{
	return PQisnonblocking(pg_get_pgconn(self)) ? Qtrue : Qfalse;
}

#sync_prepare(stmt_name, sql[, param_types ]) ⇒ PG::Result

This function has the same behavior as #async_prepare, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #prepare instead, unless you have a good reason to do so.

Returns:



1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
# File 'ext/pg_connection.c', line 1432

static VALUE
pgconn_sync_prepare(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE name, command, in_paramtypes;
	VALUE param;
	int i = 0;
	int nParams = 0;
	Oid *paramTypes = NULL;
	const char *name_cstr;
	const char *command_cstr;
	int enc_idx = this->enc_idx;

	rb_scan_args(argc, argv, "21", &name, &command, &in_paramtypes);
	name_cstr = pg_cstr_enc(name, enc_idx);
	command_cstr = pg_cstr_enc(command, enc_idx);

	if(! NIL_P(in_paramtypes)) {
		Check_Type(in_paramtypes, T_ARRAY);
		nParams = (int)RARRAY_LEN(in_paramtypes);
		paramTypes = ALLOC_N(Oid, nParams);
		for(i = 0; i < nParams; i++) {
			param = rb_ary_entry(in_paramtypes, i);
			if(param == Qnil)
				paramTypes[i] = 0;
			else
				paramTypes[i] = NUM2UINT(param);
		}
	}
	result = gvl_PQprepare(this->pgconn, name_cstr, command_cstr, nParams, paramTypes);

	xfree(paramTypes);

	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);
	return rb_pgresult;
}

#sync_put_copy_data(*args) ⇒ Object

**** PG::Connection INSTANCE METHODS: COPY *****



2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
# File 'ext/pg_connection.c', line 2554

static VALUE
pgconn_sync_put_copy_data(int argc, VALUE *argv, VALUE self)
{
	int ret;
	int len;
	t_pg_connection *this = pg_get_connection_safe( self );
	VALUE value;
	VALUE buffer = Qnil;
	VALUE encoder;
	VALUE intermediate;
	t_pg_coder *p_coder = NULL;

	rb_scan_args( argc, argv, "11", &value, &encoder );

	if( NIL_P(encoder) ){
		if( NIL_P(this->encoder_for_put_copy_data) ){
			buffer = value;
		} else {
			p_coder = RTYPEDDATA_DATA( this->encoder_for_put_copy_data );
		}
	} else {
		/* Check argument type and use argument encoder */
		TypedData_Get_Struct(encoder, t_pg_coder, &pg_coder_type, p_coder);
	}

	if( p_coder ){
		t_pg_coder_enc_func enc_func;
		int enc_idx = this->enc_idx;

		enc_func = pg_coder_enc_func( p_coder );
		len = enc_func( p_coder, value, NULL, &intermediate, enc_idx);

		if( len == -1 ){
			/* The intermediate value is a String that can be used directly. */
			buffer = intermediate;
		} else {
			buffer = rb_str_new(NULL, len);
			len = enc_func( p_coder, value, RSTRING_PTR(buffer), &intermediate, enc_idx);
			rb_str_set_len( buffer, len );
		}
	}

	Check_Type(buffer, T_STRING);

	ret = gvl_PQputCopyData(this->pgconn, RSTRING_PTR(buffer), RSTRING_LENINT(buffer));
	if(ret == -1)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(this->pgconn));

	RB_GC_GUARD(intermediate);
	RB_GC_GUARD(buffer);

	return (ret) ? Qtrue : Qfalse;
}

#sync_put_copy_end(*args) ⇒ Object



2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
# File 'ext/pg_connection.c', line 2608

static VALUE
pgconn_sync_put_copy_end(int argc, VALUE *argv, VALUE self)
{
	VALUE str;
	int ret;
	const char *error_message = NULL;
	t_pg_connection *this = pg_get_connection_safe( self );

	if (rb_scan_args(argc, argv, "01", &str) == 0)
		error_message = NULL;
	else
		error_message = pg_cstr_enc(str, this->enc_idx);

	ret = gvl_PQputCopyEnd(this->pgconn, error_message);
	if(ret == -1)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(this->pgconn));

	return (ret) ? Qtrue : Qfalse;
}

#sync_resetObject



558
559
560
561
562
563
564
# File 'ext/pg_connection.c', line 558

static VALUE
pgconn_sync_reset( VALUE self )
{
	pgconn_close_socket_io( self );
	gvl_PQreset( pg_get_pgconn(self) );
	return self;
}

#sync_set_client_encoding(encoding) ⇒ Object

This function has the same behavior as #async_set_client_encoding, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #set_client_encoding instead, unless you have a good reason to do so.



2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
# File 'ext/pg_connection.c', line 2953

static VALUE
pgconn_sync_set_client_encoding(VALUE self, VALUE str)
{
	PGconn *conn = pg_get_pgconn( self );

	rb_check_frozen(self);
	Check_Type(str, T_STRING);

	if ( (gvl_PQsetClientEncoding(conn, StringValueCStr(str))) == -1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	pgconn_set_internal_encoding_index( self );

	return Qnil;
}

#sync_setnonblocking(state) ⇒ Object



2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
# File 'ext/pg_connection.c', line 2169

static VALUE
pgconn_sync_setnonblocking(VALUE self, VALUE state)
{
	int arg;
	PGconn *conn = pg_get_pgconn(self);
	rb_check_frozen(self);
	if(state == Qtrue)
		arg = 1;
	else if (state == Qfalse)
		arg = 0;
	else
		rb_raise(rb_eArgError, "Boolean value expected");

	if(PQsetnonblocking(conn, arg) == -1)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}

#trace(stream) ⇒ nil

Enables tracing message passing between backend. The trace message will be written to the stream stream, which must implement a method fileno that returns a writable file descriptor.

Returns:

  • (nil)


2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
# File 'ext/pg_connection.c', line 2737

static VALUE
pgconn_trace(VALUE self, VALUE stream)
{
	VALUE fileno;
	FILE *new_fp;
	int old_fd, new_fd;
	VALUE new_file;
	t_pg_connection *this = pg_get_connection_safe( self );

	rb_check_frozen(self);
	if(!rb_respond_to(stream,rb_intern("fileno")))
		rb_raise(rb_eArgError, "stream does not respond to method: fileno");

	fileno = rb_funcall(stream, rb_intern("fileno"), 0);
	if(fileno == Qnil)
		rb_raise(rb_eArgError, "can't get file descriptor from stream");

	/* Duplicate the file descriptor and re-open
	 * it. Then, make it into a ruby File object
	 * and assign it to an instance variable.
	 * This prevents a problem when the File
	 * object passed to this function is closed
	 * before the connection object is. */
	old_fd = NUM2INT(fileno);
	new_fd = dup(old_fd);
	new_fp = fdopen(new_fd, "w");

	if(new_fp == NULL)
		rb_raise(rb_eArgError, "stream is not writable");

	new_file = rb_funcall(rb_cIO, rb_intern("new"), 1, INT2NUM(new_fd));
	RB_OBJ_WRITE(self, &this->trace_stream, new_file);

	PQtrace(this->pgconn, new_fp);
	return Qnil;
}

#transactionObject

call-seq:

conn.transaction { |conn| ... } -> result of the block

Executes a BEGIN at the start of the block, and a COMMIT at the end of the block, or ROLLBACK if any exception occurs.



305
306
307
308
309
310
311
312
313
314
315
316
317
# File 'lib/pg/connection.rb', line 305

def transaction
	rollback = false
	exec "BEGIN"
	yield(self)
rescue Exception
	rollback = true
	cancel if transaction_status == PG::PQTRANS_ACTIVE
	block
	exec "ROLLBACK"
	raise
ensure
	exec "COMMIT" unless rollback
end

#transaction_statusObject

returns one of the following statuses:

PQTRANS_IDLE    = 0 (connection idle)
PQTRANS_ACTIVE  = 1 (command in progress)
PQTRANS_INTRANS = 2 (idle, within transaction block)
PQTRANS_INERROR = 3 (idle, within failed transaction)
PQTRANS_UNKNOWN = 4 (cannot determine status)


811
812
813
814
815
# File 'ext/pg_connection.c', line 811

static VALUE
pgconn_transaction_status(VALUE self)
{
	return INT2NUM(PQtransactionStatus(pg_get_pgconn(self)));
}

#ttyObject

Obsolete function.



735
736
737
738
739
# File 'ext/pg_connection.c', line 735

static VALUE
pgconn_tty(VALUE self)
{
	return rb_str_new2("");
}

#type_map_for_queriesTypeMap

Returns the default TypeMap that is currently set for type casts of query bind parameters.

Returns:



4252
4253
4254
4255
4256
4257
4258
# File 'ext/pg_connection.c', line 4252

static VALUE
pgconn_type_map_for_queries_get(VALUE self)
{
	t_pg_connection *this = pg_get_connection( self );

	return this->type_map_for_queries;
}

#type_map_for_queries=(typemap) ⇒ Object

Set the default TypeMap that is used for type casts of query bind parameters.

typemap must be a kind of PG::TypeMap .



4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
# File 'ext/pg_connection.c', line 4228

static VALUE
pgconn_type_map_for_queries_set(VALUE self, VALUE typemap)
{
	t_pg_connection *this = pg_get_connection( self );
	t_typemap *tm;
	UNUSED(tm);

	rb_check_frozen(self);
	/* Check type of method param */
	TypedData_Get_Struct(typemap, t_typemap, &pg_typemap_type, tm);

	RB_OBJ_WRITE(self, &this->type_map_for_queries, typemap);

	return typemap;
}

#type_map_for_resultsTypeMap

Returns the default TypeMap that is currently set for type casts of result values.

Returns:



4290
4291
4292
4293
4294
4295
4296
# File 'ext/pg_connection.c', line 4290

static VALUE
pgconn_type_map_for_results_get(VALUE self)
{
	t_pg_connection *this = pg_get_connection( self );

	return this->type_map_for_results;
}

#type_map_for_results=(typemap) ⇒ Object

Set the default TypeMap that is used for type casts of result values.

typemap must be a kind of PG::TypeMap .



4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
# File 'ext/pg_connection.c', line 4269

static VALUE
pgconn_type_map_for_results_set(VALUE self, VALUE typemap)
{
	t_pg_connection *this = pg_get_connection( self );
	t_typemap *tm;
	UNUSED(tm);

	rb_check_frozen(self);
	TypedData_Get_Struct(typemap, t_typemap, &pg_typemap_type, tm);
	RB_OBJ_WRITE(self, &this->type_map_for_results, typemap);

	return typemap;
}

#PG::Connection.unescape_bytea(string) ⇒ Object

Converts an escaped string representation of binary data into binary data — the reverse of #escape_bytea. This is needed when retrieving bytea data in text format, but not when retrieving it in binary format.



1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
# File 'ext/pg_connection.c', line 1713

static VALUE
pgconn_s_unescape_bytea(VALUE self, VALUE str)
{
	unsigned char *from, *to;
	size_t to_len;
	VALUE ret;

	UNUSED( self );

	Check_Type(str, T_STRING);
	from = (unsigned char*)StringValueCStr(str);

	to = PQunescapeBytea(from, &to_len);

	ret = rb_str_new((char*)to, to_len);
	PQfreemem(to);
	return ret;
}

#untracenil

Disables the message tracing.

Returns:

  • (nil)


2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
# File 'ext/pg_connection.c', line 2780

static VALUE
pgconn_untrace(VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );

	PQuntrace(this->pgconn);
	rb_funcall(this->trace_stream, rb_intern("close"), 0);
	RB_OBJ_WRITE(self, &this->trace_stream, Qnil);
	return Qnil;
}

#userObject

Returns the authenticated user name.



646
647
648
649
650
651
652
# File 'ext/pg_connection.c', line 646

static VALUE
pgconn_user(VALUE self)
{
	char *user = PQuser(pg_get_pgconn(self));
	if (!user) return Qnil;
	return rb_str_new2(user);
}

#wait_for_notify([ timeout ]) {|event, pid, payload| ... } ⇒ String Also known as: notifies_wait

Blocks while waiting for notification(s), or until the optional timeout is reached, whichever comes first. timeout is measured in seconds and can be fractional.

Returns nil if timeout is reached, the name of the NOTIFY event otherwise. If used in block form, passes the name of the NOTIFY event, the generating pid and the optional payload string into the block.

Yields:

  • (event, pid, payload)

Returns:

  • (String)


2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
# File 'ext/pg_connection.c', line 2514

static VALUE
pgconn_wait_for_notify(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGnotify *pnotification;
	struct timeval timeout;
	struct timeval *ptimeout = NULL;
	VALUE timeout_in = Qnil, relname = Qnil, be_pid = Qnil, extra = Qnil;
	double timeout_sec;

	rb_scan_args( argc, argv, "01", &timeout_in );

	if ( RTEST(timeout_in) ) {
		timeout_sec = NUM2DBL( timeout_in );
		timeout.tv_sec = (time_t)timeout_sec;
		timeout.tv_usec = (suseconds_t)( (timeout_sec - (long)timeout_sec) * 1e6 );
		ptimeout = &timeout;
	}

	pnotification = (PGnotify*) wait_socket_readable( self, ptimeout, notify_readable);

	/* Return nil if the select timed out */
	if ( !pnotification ) return Qnil;

	relname = rb_str_new2( pnotification->relname );
	PG_ENCODING_SET_NOCHECK( relname, this->enc_idx );
	be_pid = INT2NUM( pnotification->be_pid );
	if ( *pnotification->extra ) {
		extra = rb_str_new2( pnotification->extra );
		PG_ENCODING_SET_NOCHECK( extra, this->enc_idx );
	}
	PQfreemem( pnotification );

	if ( rb_block_given_p() )
		rb_yield_values( 3, relname, be_pid, extra );

	return relname;
}