Class: PGconn

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

Overview

******************************************************************

The class to access PostgreSQL RDBMS, based on the libpq interface,
provides convenient OO methods to interact with PostgreSQL.

For example, to send query to the database on the localhost:
   require 'pg'
   conn = PGconn.open(:dbname => 'test')
   res = conn.exec('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 PGresult class for information on working with the results of a query.

Constant Summary collapse

CONNECT_ARGUMENT_ORDER =

The order the options are passed to the ::connect method.

%w[host port options tty dbname user password]
VERSION =

Library version

rb_str_new2(VERSION)
CONNECTION_OK =

Connection succeeded

INT2FIX(CONNECTION_OK)
CONNECTION_BAD =

Connection failed

INT2FIX(CONNECTION_BAD)
CONNECTION_STARTED =

Waiting for connection to be made.

INT2FIX(CONNECTION_STARTED)
CONNECTION_MADE =

Connection OK; waiting to send.

INT2FIX(CONNECTION_MADE)
CONNECTION_AWAITING_RESPONSE =

Waiting for a response from the server.

INT2FIX(CONNECTION_AWAITING_RESPONSE)
CONNECTION_AUTH_OK =

Received authentication; waiting for backend start-up to finish.

INT2FIX(CONNECTION_AUTH_OK)
CONNECTION_SSL_STARTUP =

Negotiating SSL encryption.

INT2FIX(CONNECTION_SSL_STARTUP)
CONNECTION_SETENV =

Negotiating environment-driven parameter settings.

INT2FIX(CONNECTION_SETENV)
PGRES_POLLING_READING =

Async connection is waiting to read

INT2FIX(PGRES_POLLING_READING)
PGRES_POLLING_WRITING =

Async connection is waiting to write

INT2FIX(PGRES_POLLING_WRITING)
PGRES_POLLING_FAILED =

Async connection failed or was reset

INT2FIX(PGRES_POLLING_FAILED)
PGRES_POLLING_OK =

Async connection succeeded

INT2FIX(PGRES_POLLING_OK)
PQTRANS_IDLE =

Transaction is currently idle (#transaction_status)

INT2FIX(PQTRANS_IDLE)
PQTRANS_ACTIVE =

Transaction is currently active; query has been sent to the server, but not yet completed. (#transaction_status)

INT2FIX(PQTRANS_ACTIVE)
PQTRANS_INTRANS =

Transaction is currently idle, in a valid transaction block (#transaction_status)

INT2FIX(PQTRANS_INTRANS)
PQTRANS_INERROR =

Transaction is currently idle, in a failed transaction block (#transaction_status)

INT2FIX(PQTRANS_INERROR)
PQTRANS_UNKNOWN =

Transaction’s connection is bad (#transaction_status)

INT2FIX(PQTRANS_UNKNOWN)
PQERRORS_TERSE =

Terse error verbosity level (#set_error_verbosity)

INT2FIX(PQERRORS_TERSE)
PQERRORS_DEFAULT =

Default error verbosity level (#set_error_verbosity)

INT2FIX(PQERRORS_DEFAULT)
PQERRORS_VERBOSE =

Verbose error verbosity level (#set_error_verbosity)

INT2FIX(PQERRORS_VERBOSE)
INV_WRITE =

Flag for #lo_creat, #lo_open – open for writing

INT2FIX(INV_WRITE)
INV_READ =

Flag for #lo_creat, #lo_open – open for reading

INT2FIX(INV_READ)
SEEK_SET =

Flag for #lo_lseek – seek from object start

INT2FIX(SEEK_SET)
SEEK_CUR =

Flag for #lo_lseek – seek from current position

INT2FIX(SEEK_CUR)
SEEK_END =

Flag for #lo_lseek – seek from object end

INT2FIX(SEEK_END)

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Object

call-seq:

PGconn.new -> PGconn
PGconn.new(connection_hash) -> PGconn
PGconn.new(connection_string) -> PGconn
PGconn.new(host, port, options, tty, dbname, user, password) ->  PGconn

Create a connection to the specified server.

host

server hostname

hostaddr

server address (avoids hostname lookup, overrides host)

port

server port number

dbname

connecting database name

user

login user name

password

login password

connect_timeout

maximum time to wait for connection to succeed

options

backend options

tty

(ignored in newer versions of PostgreSQL)

sslmode

(disable|allow|prefer|require)

krbsrvname

kerberos service name

gsslib

GSS library to use for GSSAPI authentication

service

service name to use for additional parameters

Examples:

# Connect using all defaults
PGconn.connect

# As a Hash
PGconn.connect( :dbname => 'test', :port => 5432 )

# As a String
PGconn.connect( "dbname=test port=5432" )

# As an Array
PGconn.connect( nil, 5432, nil, nil, 'test', nil, nil )

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



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# File 'ext/pg.c', line 298

static VALUE
pgconn_init(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = NULL;
	VALUE conninfo;
	VALUE error;
#ifdef M17N_SUPPORTED	
	rb_encoding *enc;
	const char *encname;
#endif

	conninfo = rb_funcall2( rb_cPGconn, rb_intern("parse_connect_args"), argc, argv );
	conn = PQconnectdb(StringValuePtr(conninfo));

	if(conn == NULL)
		rb_raise(rb_ePGError, "PQconnectStart() unable to allocate structure");

	Check_Type(self, T_DATA);
	DATA_PTR(self) = conn;

	if (PQstatus(conn) == CONNECTION_BAD) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}

#ifdef M17N_SUPPORTED
	/* If Ruby has its Encoding.default_internal set, set PostgreSQL's client_encoding 
	 * to match */
	if (( enc = rb_default_internal_encoding() )) {
		encname = pgconn_get_rb_encoding_as_pg_encname( enc );
		if ( PQsetClientEncoding(conn, encname) != 0 )
			rb_warn( "Failed to set the default_internal encoding to %s: '%s'",
			         encname, PQerrorMessage(conn) );
	}
#endif

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

Class Method Details

.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

Returns:

  • (Array) 


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# File 'ext/pg.c', line 411

static VALUE
pgconn_s_conndefaults(VALUE self)
{
	PQconninfoOption *options = PQconndefaults();
	VALUE ary = rb_ary_new();
	VALUE hash;
	int i = 0;

	for(i = 0; options[i].keyword != NULL; i++) {
		hash = rb_hash_new();
		if(options[i].keyword)
			rb_hash_aset(hash, ID2SYM(rb_intern("keyword")), 
				rb_str_new2(options[i].keyword));
		if(options[i].envvar)
			rb_hash_aset(hash, ID2SYM(rb_intern("envvar")), 
				rb_str_new2(options[i].envvar));
		if(options[i].compiled)
			rb_hash_aset(hash, ID2SYM(rb_intern("compiled")), 
				rb_str_new2(options[i].compiled));
		if(options[i].val)
			rb_hash_aset(hash, ID2SYM(rb_intern("val")), 
				rb_str_new2(options[i].val));
		if(options[i].label)
			rb_hash_aset(hash, ID2SYM(rb_intern("label")), 
				rb_str_new2(options[i].label));
		if(options[i].dispchar)
			rb_hash_aset(hash, ID2SYM(rb_intern("dispchar")), 
				rb_str_new2(options[i].dispchar));
		rb_hash_aset(hash, ID2SYM(rb_intern("dispsize")), 
			INT2NUM(options[i].dispsize));
		rb_ary_push(ary, hash);
	}
	PQconninfoFree(options);
	return ary;
}

.connect_start(connection_hash) ⇒ PGconn .connect_start(connection_string) ⇒ PGconn .connect_start(host, port, options, tty, dbname, login, password) ⇒ PGconn

This is an asynchronous version of PGconn.connect().

Use PGconn#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 PGconn#internal_encoding=. You can also set it automatically by setting ENV, or include the ‘options’ connection parameter.

Overloads:

  • .connect_start(connection_hash) ⇒ PGconn

    Returns:

  • .connect_start(connection_string) ⇒ PGconn

    Returns:

  • .connect_start(host, port, options, tty, dbname, login, password) ⇒ PGconn

    Returns:



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# File 'ext/pg.c', line 357

static VALUE
pgconn_s_connect_start(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = NULL;
	VALUE rb_conn;
	VALUE conninfo;
	VALUE error;

	/*
	 * PGconn.connect_start must act as both alloc() and initialize()
	 * because it is not invoked by calling new().
	 */
	rb_conn = pgconn_alloc(rb_cPGconn);

	conninfo = rb_funcall2( rb_cPGconn, rb_intern("parse_connect_args"), argc, argv );
	conn = PQconnectStart(StringValuePtr(conninfo));

	if(conn == NULL)
		rb_raise(rb_ePGError, "PQconnectStart() unable to allocate structure");
	if (PQstatus(conn) == CONNECTION_BAD) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}

	Check_Type(rb_conn, T_DATA);
	DATA_PTR(rb_conn) = conn;

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

.encrypt_password(password, username) ⇒ String

This function is intended to be used by client applications that send commands like: ALTER USER joe PASSWORD ‘pwd’. The arguments are the cleartext password, and the SQL name of the user it is for.

Return value is the encrypted password.

Returns:

  • (String) 


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# File 'ext/pg.c', line 459

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

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

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

	OBJ_INFECT( rval, password );
	OBJ_INFECT( rval, username );

	return rval;
}

.escape_bytea(string) ⇒ String .escape_bytea(string) ⇒ String #DEPRECATEDD

Connection instance method for versions of 8.1 and higher of libpq uses PQescapeByteaConn, which is safer. Avoid calling as a class method, the class method uses the deprecated PQescapeBytea() API function.

Use the instance method version of this function, it is safer than the class method.

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.

Overloads:

  • .escape_bytea(string) ⇒ String

    Returns:

    • (String)
  • .escape_bytea(string) ⇒ String #DEPRECATEDD

    Returns:

    • (String #DEPRECATEDD) 


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# File 'ext/pg.c', line 1368

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_class(self) == rb_cPGconn) {
		to = PQescapeByteaConn(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);
	OBJ_INFECT(ret, str);
	PQfreemem(to);
	return ret;
}

.escape_string(str) ⇒ String .escape_string(str) ⇒ String #DEPRECATEDD

Connection instance method for versions of 8.1 and higher of libpq uses PQescapeStringConn, which is safer. Avoid calling as a class method, the class method uses the deprecated PQescapeString() API function.

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.

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

Overloads:

  • .escape_string(str) ⇒ String

    Returns:

    • (String)
  • .escape_string(str) ⇒ String #DEPRECATEDD

    Returns:

    • (String #DEPRECATEDD) 


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# File 'ext/pg.c', line 1303

static VALUE
pgconn_s_escape(VALUE self, VALUE string)
{
	char *escaped;
	int size,error;
	VALUE result;
#ifdef M17N_SUPPORTED	
	rb_encoding* enc;
#endif

	Check_Type(string, T_STRING);

	escaped = ALLOC_N(char, RSTRING_LEN(string) * 2 + 1);
	if(rb_obj_class(self) == rb_cPGconn) {
		size = PQescapeStringConn(get_pgconn(self), escaped, 
			RSTRING_PTR(string), RSTRING_LEN(string), &error);
		if(error) {
			xfree(escaped);
			rb_raise(rb_ePGError, "%s", PQerrorMessage(get_pgconn(self)));
		}
	} else {
		size = PQescapeString(escaped, RSTRING_PTR(string),
			RSTRING_LEN(string));
	}
	result = rb_str_new(escaped, size);
	xfree(escaped);
	OBJ_INFECT(result, string);

#ifdef M17N_SUPPORTED
	if(rb_obj_class(self) == rb_cPGconn) {
		enc = pgconn_get_client_encoding_as_rb_encoding(get_pgconn(self));
	} else {
		enc = rb_enc_get(string);
	}
	rb_enc_associate(result, enc);
#endif

	return result;
}

.isthreadsafe ⇒ Boolean

Returns true if libpq is thread safe, false otherwise.

Returns:

  • (Boolean) 


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# File 'ext/pg.c', line 485

static VALUE
pgconn_s_isthreadsafe(VALUE self)
{
	return PQisthreadsafe() ? Qtrue : Qfalse;
}

.parse_connect_args(*args) ⇒ String

Parse the connection args into a connection-parameter string

Parameters:

  • args (Array<String>) —

    the connection parameters

Returns:

  • (String) —

    a connection parameters string



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# File 'lib/pg.rb', line 35

def self::parse_connect_args( *args )
	return '' if args.empty?

	# This will be swapped soon for code that makes options like those required for
	# PQconnectdbParams()/PQconnectStartParams(). For now, stick to an options string for
	# PQconnectdb()/PQconnectStart().
	connopts = []

	# Handle an options hash first
	if args.last.is_a?( Hash )
		opthash = args.pop 
		opthash.each do |key, val|
			connopts.push( "%s=%s" % [key, PGconn.quote_connstr(val)] )
		end
	end

	# Option string style
	if args.length == 1 && args.first.to_s.index( '=' )
		connopts.unshift( args.first )

	# Append positional parameters
	else
		args.each_with_index do |val, i|
			next unless val # Skip nil placeholders

			key = CONNECT_ARGUMENT_ORDER[ i ] or
				raise ArgumentError, "Extra positional parameter %d: %p" % [ i+1, val ]
			connopts.push( "%s=%s" % [key, PGconn.quote_connstr(val.to_s)] )
		end
	end

	return connopts.join(' ')
end

.quote_connstr(value) ⇒ String

Quote the given value for use in a connection-parameter string.

Parameters:

  • value (String) —

    the option value to be quoted.

Returns:

  • (String) 


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# File 'lib/pg.rb', line 27

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

.quote_ident(str) ⇒ String .quote_ident(str) ⇒ 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 PGconn.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.

Overloads:

  • .quote_ident(str) ⇒ String

    Returns:

    • (String)
  • .quote_ident(str) ⇒ String

    Returns:

    • (String) 


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# File 'ext/pg.c', line 2507

static VALUE
pgconn_s_quote_ident(VALUE self, VALUE in_str)
{
	VALUE ret;
	char *str = StringValuePtr(in_str);
	/* result size at most NAMEDATALEN*2 plus surrounding
	 * double-quotes. */
	char buffer[NAMEDATALEN*2+2];
	unsigned int i=0,j=0;

	if(strlen(str) >= NAMEDATALEN) {
		rb_raise(rb_eArgError, 
			"Input string is longer than NAMEDATALEN-1 (%d)",
			NAMEDATALEN-1);
	}
	buffer[j++] = '"';
	for(i = 0; i < strlen(str) && str[i]; i++) {
		if(str[i] == '"') 
			buffer[j++] = '"';
		buffer[j++] = str[i];
	}
	buffer[j++] = '"';
	ret = rb_str_new(buffer,j);
	OBJ_INFECT(ret, in_str);
	return ret;
}

.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.



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# File 'ext/pg.c', line 1401

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

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

	to = PQunescapeBytea(from, &to_len);

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

Instance Method Details

#async_exec(sql[, params, result_format ]) ⇒ PGresult #async_exec(sql[, params, result_format ]) {|pg_result| ... } ⇒ Object Also known as: async_query

This function has the same behavior as PGconn#exec, except that it’s implemented using asynchronous command processing and ruby’s rb_thread_select in order to allow other threads to process while waiting for the server to complete the request.

Overloads:

  • #async_exec(sql[, params, result_format ]) ⇒ PGresult

    Returns:

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

    Yields:

    • (pg_result) 


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# File 'ext/pg.c', line 2660

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

	/* remove any remaining results from the queue */
	pgconn_get_last_result( self );

	pgconn_send_query( argc, argv, self );
	pgconn_block( 0, NULL, self );
	rb_pgresult = pgconn_get_last_result( self );

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

#backend_pid ⇒ Fixnum

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

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 823

static VALUE
pgconn_backend_pid(VALUE self)
{
	return INT2NUM(PQbackendPID(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) 


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# File 'ext/pg.c', line 2548

static VALUE
pgconn_block( int argc, VALUE *argv, VALUE self ) {
	PGconn *conn = get_pgconn(self);
	int sd = PQsocket(conn);
	int ret;
	struct timeval timeout;
	struct timeval *ptimeout = NULL;
	VALUE timeout_in;
	double timeout_sec;
	fd_set sd_rset;
#ifdef _WIN32
	fd_set crt_sd_rset;
#endif

	/* Always set a timeout in WIN32, as rb_thread_select() sometimes
	 * doesn't return when a second ruby thread is running although data
	 * could be read. So we use timeout-based polling instead.
	 */
#if defined(_WIN32)
	timeout.tv_sec = 0;
	timeout.tv_usec = 10000;
	ptimeout = &timeout;
#endif

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

	PQconsumeInput( conn );

	while ( PQisBusy(conn) ) {
		FD_ZERO( &sd_rset );
		FD_SET( sd, &sd_rset );

#ifdef _WIN32
		create_crt_fd(&sd_rset, &crt_sd_rset);
#endif

		ret = rb_thread_select (sd+1, &sd_rset, NULL, NULL, ptimeout );

#ifdef _WIN32
		cleanup_crt_fd(&sd_rset, &crt_sd_rset);
#endif

		/* Return false if there was a timeout argument and the select() timed out */
		if ( ret == 0 && argc ) 
			return Qfalse;

		PQconsumeInput( conn );
	} 

	return Qtrue;
}

#cancel ⇒ String

Requests cancellation of the command currently being processed. (Only implemented in PostgreSQL >= 8.0)

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

Returns:

  • (String) 


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# File 'ext/pg.c', line 1954

static VALUE
pgconn_cancel(VALUE self)
{
#ifdef HAVE_PQGETCANCEL
	char errbuf[256];
	PGcancel *cancel;
	VALUE retval;
	int ret;

	cancel = PQgetCancel(get_pgconn(self));
	if(cancel == NULL)
		rb_raise(rb_ePGError,"Invalid connection!");

	ret = PQcancel(cancel, errbuf, 256);
	if(ret == 1)
		retval = Qnil;
	else
		retval = rb_str_new2(errbuf);

	PQfreeCancel(cancel);
	return retval;
#else
	rb_notimplement();
#endif
}

#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

Returns:

  • (Array) 


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# File 'ext/pg.c', line 411

static VALUE
pgconn_s_conndefaults(VALUE self)
{
	PQconninfoOption *options = PQconndefaults();
	VALUE ary = rb_ary_new();
	VALUE hash;
	int i = 0;

	for(i = 0; options[i].keyword != NULL; i++) {
		hash = rb_hash_new();
		if(options[i].keyword)
			rb_hash_aset(hash, ID2SYM(rb_intern("keyword")), 
				rb_str_new2(options[i].keyword));
		if(options[i].envvar)
			rb_hash_aset(hash, ID2SYM(rb_intern("envvar")), 
				rb_str_new2(options[i].envvar));
		if(options[i].compiled)
			rb_hash_aset(hash, ID2SYM(rb_intern("compiled")), 
				rb_str_new2(options[i].compiled));
		if(options[i].val)
			rb_hash_aset(hash, ID2SYM(rb_intern("val")), 
				rb_str_new2(options[i].val));
		if(options[i].label)
			rb_hash_aset(hash, ID2SYM(rb_intern("label")), 
				rb_str_new2(options[i].label));
		if(options[i].dispchar)
			rb_hash_aset(hash, ID2SYM(rb_intern("dispchar")), 
				rb_str_new2(options[i].dispchar));
		rb_hash_aset(hash, ID2SYM(rb_intern("dispsize")), 
			INT2NUM(options[i].dispsize));
		rb_ary_push(ary, hash);
	}
	PQconninfoFree(options);
	return ary;
}

#connect_poll ⇒ Fixnum

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:

conn = PGconn.connect_start("dbname=mydatabase")
socket = IO.for_fd(conn.socket)
status = conn.connect_poll
while(status != PGconn::PGRES_POLLING_OK) do
  # do some work while waiting for the connection to complete
  if(status == PGconn::PGRES_POLLING_READING)
    if(not select([socket], [], [], 10.0))
      raise "Asynchronous connection timed out!"
    end
  elsif(status == PGconn::PGRES_POLLING_WRITING)
    if(not select([], [socket], [], 10.0))
      raise "Asynchronous connection timed out!"
    end
  end
  status = conn.connect_poll
end
# now conn.status == CONNECTION_OK, and connection
# is ready.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 529

static VALUE
pgconn_connect_poll(VALUE self)
{
	PostgresPollingStatusType status;
	status = PQconnectPoll(get_pgconn(self));
	return INT2FIX((int)status);
}

#connection_needs_password ⇒ Boolean

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

Returns:

  • (Boolean) 


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# File 'ext/pg.c', line 836

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

#connection_used_password ⇒ Boolean

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

Returns:

  • (Boolean) 


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# File 'ext/pg.c', line 849

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

#consume_input ⇒ Object

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.



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# File 'ext/pg.c', line 1836

static VALUE
pgconn_consume_input(self)
VALUE self;

#db ⇒ Object

Returns the connected database name.



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# File 'ext/pg.c', line 605

static VALUE
pgconn_db(VALUE self)
{
	char *db = PQdb(get_pgconn(self));
	if (!db) return Qnil;
	return rb_tainted_str_new2(db);
}

#describe_portal(portal_name) ⇒ PGresult

Retrieve information about the portal portal_name.

Returns:



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# File 'ext/pg.c', line 1235

static VALUE
pgconn_describe_portal(self, stmt_name)
VALUE self, stmt_name;

#describe_prepared(statement_name) ⇒ PGresult

Retrieve information about the prepared statement statement_name.

Returns:



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# File 'ext/pg.c', line 1208

static VALUE
pgconn_describe_prepared(VALUE self, VALUE stmt_name)
{
	PGresult *result;
	VALUE rb_pgresult;
	PGconn *conn = get_pgconn(self);
	char *stmt;
	if(stmt_name == Qnil) {
		stmt = NULL;
	}
	else {
		Check_Type(stmt_name, T_STRING);
		stmt = StringValuePtr(stmt_name);
	}
	result = PQdescribePrepared(conn, stmt);
	rb_pgresult = new_pgresult(result, conn);
	pgresult_check(self, rb_pgresult);
	return rb_pgresult;
}

#error ⇒ String

Returns the error message about connection.

Returns:

  • (String) 


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# File 'ext/pg.c', line 791

static VALUE
pgconn_error_message(VALUE self)
{
	char *error = PQerrorMessage(get_pgconn(self));
	if (!error) return Qnil;
	return rb_tainted_str_new2(error);
}

#escape_bytea(string) ⇒ String #escape_bytea(string) ⇒ String #DEPRECATEDD

Connection instance method for versions of 8.1 and higher of libpq uses PQescapeByteaConn, which is safer. Avoid calling as a class method, the class method uses the deprecated PQescapeBytea() API function.

Use the instance method version of this function, it is safer than the class method.

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.

Overloads:

  • #escape_bytea(string) ⇒ String

    Returns:

    • (String)
  • #escape_bytea(string) ⇒ String #DEPRECATEDD

    Returns:

    • (String #DEPRECATEDD) 


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# File 'ext/pg.c', line 1368

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_class(self) == rb_cPGconn) {
		to = PQescapeByteaConn(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);
	OBJ_INFECT(ret, str);
	PQfreemem(to);
	return ret;
}

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

Connection instance method for versions of 8.1 and higher of libpq uses PQescapeStringConn, which is safer. Avoid calling as a class method, the class method uses the deprecated PQescapeString() API function.

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.

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

Overloads:

  • #escape_string(str) ⇒ String

    Returns:

    • (String)
  • #escape_string(str) ⇒ String #DEPRECATEDD

    Returns:

    • (String #DEPRECATEDD) 


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# File 'ext/pg.c', line 1303

static VALUE
pgconn_s_escape(VALUE self, VALUE string)
{
	char *escaped;
	int size,error;
	VALUE result;
#ifdef M17N_SUPPORTED	
	rb_encoding* enc;
#endif

	Check_Type(string, T_STRING);

	escaped = ALLOC_N(char, RSTRING_LEN(string) * 2 + 1);
	if(rb_obj_class(self) == rb_cPGconn) {
		size = PQescapeStringConn(get_pgconn(self), escaped, 
			RSTRING_PTR(string), RSTRING_LEN(string), &error);
		if(error) {
			xfree(escaped);
			rb_raise(rb_ePGError, "%s", PQerrorMessage(get_pgconn(self)));
		}
	} else {
		size = PQescapeString(escaped, RSTRING_PTR(string),
			RSTRING_LEN(string));
	}
	result = rb_str_new(escaped, size);
	xfree(escaped);
	OBJ_INFECT(result, string);

#ifdef M17N_SUPPORTED
	if(rb_obj_class(self) == rb_cPGconn) {
		enc = pgconn_get_client_encoding_as_rb_encoding(get_pgconn(self));
	} else {
		enc = rb_enc_get(string);
	}
	rb_enc_associate(result, enc);
#endif

	return result;
}

#exec(sql[, params, result_format ]) ⇒ PGresult #exec(sql[, params, result_format ]) {|pg_result| ... } ⇒ Object Also known as: query

Sends SQL query request specified by sql to PostgreSQL. Returns a PGresult instance on success. On failure, it raises a PGError exception.

params is an optional 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   => Fixnum (oid of type of bind parameter)
   :format => Fixnum (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, $1, $2, 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.

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

Overloads:

  • #exec(sql[, params, result_format ]) ⇒ PGresult

    Returns:

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

    Yields:

    • (pg_result) 


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# File 'ext/pg.c', line 895

static VALUE
pgconn_exec(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE command, params, in_res_fmt;
	VALUE param, param_type, param_value, param_format;
	VALUE param_value_tmp;
	VALUE sym_type, sym_value, sym_format;
	VALUE gc_array;
	int i=0;
	int nParams;
	Oid *paramTypes;
	char ** paramValues;
	int *paramLengths;
	int *paramFormats;
	int resultFormat;

	rb_scan_args(argc, argv, "12", &command, &params, &in_res_fmt);

	Check_Type(command, T_STRING);

	/* If called with no parameters, use PQexec */
	if(NIL_P(params)) {
		result = PQexec(conn, StringValuePtr(command));
		rb_pgresult = new_pgresult(result, conn);
		pgresult_check(self, rb_pgresult);
		if (rb_block_given_p()) {
			return rb_ensure(rb_yield, rb_pgresult, 
				pgresult_clear, rb_pgresult);
		}
		return rb_pgresult;
	}

	/* If called with parameters, and optionally result_format,
	 * use PQexecParams
	 */
	Check_Type(params, T_ARRAY);

	if(NIL_P(in_res_fmt)) {
		resultFormat = 0;
	}
	else {
		resultFormat = NUM2INT(in_res_fmt);
	}

	gc_array = rb_ary_new();
	rb_gc_register_address(&gc_array);
	sym_type = ID2SYM(rb_intern("type"));
	sym_value = ID2SYM(rb_intern("value"));
	sym_format = ID2SYM(rb_intern("format"));
	nParams = RARRAY_LEN(params);
	paramTypes = ALLOC_N(Oid, nParams); 
	paramValues = ALLOC_N(char *, nParams);
	paramLengths = ALLOC_N(int, nParams);
	paramFormats = ALLOC_N(int, nParams);
	for(i = 0; i < nParams; i++) {
		param = rb_ary_entry(params, i);
		if (TYPE(param) == T_HASH) {
			param_type = rb_hash_aref(param, sym_type);
			param_value_tmp = rb_hash_aref(param, sym_value);
			if(param_value_tmp == Qnil)
				param_value = param_value_tmp;
			else
				param_value = rb_obj_as_string(param_value_tmp);
			param_format = rb_hash_aref(param, sym_format);
		}
		else {
			param_type = Qnil;
			if(param == Qnil)
				param_value = param;
			else
				param_value = rb_obj_as_string(param);
			param_format = Qnil;
		}

		if(param_type == Qnil)
			paramTypes[i] = 0;
		else
			paramTypes[i] = NUM2INT(param_type);

		if(param_value == Qnil) {
			paramValues[i] = NULL;
			paramLengths[i] = 0;
		}
		else {
			Check_Type(param_value, T_STRING);
			/* make sure param_value doesn't get freed by the GC */
			rb_ary_push(gc_array, param_value);
			paramValues[i] = StringValuePtr(param_value);
			paramLengths[i] = RSTRING_LEN(param_value);
		}

		if(param_format == Qnil)
			paramFormats[i] = 0;
		else
			paramFormats[i] = NUM2INT(param_format);
	}

	result = PQexecParams(conn, StringValuePtr(command), nParams, paramTypes, 
		(const char * const *)paramValues, paramLengths, paramFormats, resultFormat);

	rb_gc_unregister_address(&gc_array);

	xfree(paramTypes);
	xfree(paramValues);
	xfree(paramLengths);
	xfree(paramFormats);

	rb_pgresult = new_pgresult(result, conn);
	pgresult_check(self, rb_pgresult);
	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, rb_pgresult, 
			pgresult_clear, rb_pgresult);
	}
	return rb_pgresult;
}

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

Execute prepared named statement specified by statement_name. Returns a PGresult instance on success. On failure, it raises a PGError exception.

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 => Fixnum (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, $1, $2, 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.

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

Overloads:

  • #exec_prepared(statement_name[, params, result_format ]) ⇒ PGresult

    Returns:

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

    Yields:

    • (pg_result) 


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# File 'ext/pg.c', line 1102

static VALUE
pgconn_exec_prepared(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE name, params, in_res_fmt;
	VALUE param, param_value, param_format;
	VALUE param_value_tmp;
	VALUE sym_value, sym_format;
	VALUE gc_array;
	int i = 0;
	int nParams;
	char ** paramValues;
	int *paramLengths;
	int *paramFormats;
	int resultFormat;


	rb_scan_args(argc, argv, "12", &name, &params, &in_res_fmt);
	Check_Type(name, T_STRING);

	if(NIL_P(params)) {
		params = rb_ary_new2(0);
		resultFormat = 0;
	}
	else {
		Check_Type(params, T_ARRAY);
	}

	if(NIL_P(in_res_fmt)) {
		resultFormat = 0;
	}
	else {
		resultFormat = NUM2INT(in_res_fmt);
	}

	gc_array = rb_ary_new();
	rb_gc_register_address(&gc_array);
	sym_value = ID2SYM(rb_intern("value"));
	sym_format = ID2SYM(rb_intern("format"));
	nParams = RARRAY_LEN(params);
	paramValues = ALLOC_N(char *, nParams);
	paramLengths = ALLOC_N(int, nParams);
	paramFormats = ALLOC_N(int, nParams);
	for(i = 0; i < nParams; i++) {
		param = rb_ary_entry(params, i);
		if (TYPE(param) == T_HASH) {
			param_value_tmp = rb_hash_aref(param, sym_value);
			if(param_value_tmp == Qnil)
				param_value = param_value_tmp;
			else
				param_value = rb_obj_as_string(param_value_tmp);
			param_format = rb_hash_aref(param, sym_format);
		}
		else {
			if(param == Qnil)
				param_value = param;
			else
				param_value = rb_obj_as_string(param);
			param_format = INT2NUM(0);
		}
		if(param_value == Qnil) {
			paramValues[i] = NULL;
			paramLengths[i] = 0;
		}
		else {
			Check_Type(param_value, T_STRING);
			/* make sure param_value doesn't get freed by the GC */
			rb_ary_push(gc_array, param_value);
			paramValues[i] = StringValuePtr(param_value);
			paramLengths[i] = RSTRING_LEN(param_value);
		}

		if(param_format == Qnil)
			paramFormats[i] = 0;
		else
			paramFormats[i] = NUM2INT(param_format);
	}

	result = PQexecPrepared(conn, StringValuePtr(name), nParams, 
		(const char * const *)paramValues, paramLengths, paramFormats, 
		resultFormat);

	rb_gc_unregister_address(&gc_array);

	xfree(paramValues);
	xfree(paramLengths);
	xfree(paramFormats);

	rb_pgresult = new_pgresult(result, conn);
	pgresult_check(self, rb_pgresult);
	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, rb_pgresult, 
			pgresult_clear, rb_pgresult);
	}
	return rb_pgresult;
}

#external_encoding ⇒ Encoding

defined in Ruby 1.9 or later.

  • Returns the server_encoding of the connected database as a Ruby Encoding object.

  • Maps ‘SQL_ASCII’ to ASCII-8BIT.

Returns:

  • (Encoding) 


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# File 'ext/pg.c', line 3917

static VALUE
pgconn_external_encoding(VALUE self)
{
	VALUE enc;
	enc = rb_iv_get(self, "@external_encoding");
	if (RTEST(enc)) {
		return enc;
	}
	else {
		int i;
		VALUE query = rb_usascii_str_new_cstr("SHOW server_encoding");
		VALUE pgresult = pgconn_exec(1, &query, self);
		VALUE enc_name = rb_ensure(enc_server_encoding_getvalue, pgresult, pgresult_clear, pgresult);

		if (strcmp("SQL_ASCII", StringValuePtr(enc_name)) == 0) {
			enc = rb_enc_from_encoding(rb_ascii8bit_encoding());
			goto cache;
		}
		for (i = 0; i < sizeof(enc_pg2ruby_mapping)/sizeof(enc_pg2ruby_mapping[0]); ++i) {
			if (strcmp(StringValuePtr(enc_name), enc_pg2ruby_mapping[i][0]) == 0) {
				enc = rb_enc_from_encoding(rb_enc_find(enc_pg2ruby_mapping[i][1]));
				goto cache;
			}
		}

		/* Ruby 1.9.1 does not supoort JOHAB */
		if (strcmp(StringValuePtr(enc_name), "JOHAB") == 0) {
			enc = rb_enc_from_encoding(find_or_create_johab());
			goto cache;
		}

		/* fallback */
		enc = rb_enc_from_encoding(rb_enc_find(StringValuePtr(enc_name)));
	}

cache:
	rb_iv_set(self, "@external_encoding", enc);
	return enc;
}

#finish ⇒ Object Also known as: close

Closes the backend connection.



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# File 'ext/pg.c', line 543

static VALUE
pgconn_finish(VALUE self)
{
	PQfinish(get_pgconn(self));
	DATA_PTR(self) = NULL;
	return Qnil;
}

#flush ⇒ Boolean

Attempts to flush any queued output data to the server. Returns true if data is successfully flushed, false if not (can only return false if connection is nonblocking. Raises PGError exception if some other failure occurred.

Returns:

  • (Boolean) 


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# File 'ext/pg.c', line 1928

static VALUE
pgconn_flush(self)
VALUE self;

#get_client_encoding ⇒ String

Returns the client encoding as a String.

Returns:

  • (String) 


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# File 'ext/pg.c', line 2421

static VALUE
pgconn_get_client_encoding(VALUE self)
{
	char *encoding = (char *)pg_encoding_to_char(PQclientEncoding(get_pgconn(self)));
	return rb_tainted_str_new2(encoding);
}

#get_copy_data([ async = false ]) ⇒ String

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

Returns:

  • (String) 


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# File 'ext/pg.c', line 2212

static VALUE
pgconn_get_copy_data(int argc, VALUE *argv, VALUE self )
{
	VALUE async_in;
	VALUE error;
	VALUE result_str;
	int ret;
	int async;
	char *buffer;
	PGconn *conn = get_pgconn(self);

	if (rb_scan_args(argc, argv, "01", &async_in) == 0)
		async = 0;
	else
		async = (async_in == Qfalse || async_in == Qnil) ? 0 : 1;

	ret = PQgetCopyData(conn, &buffer, async);
	if(ret == -2) { // error
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	if(ret == -1) { // No data left
		return Qnil;
	}
	if(ret == 0) { // would block
		return Qfalse;
	}
	result_str = rb_tainted_str_new(buffer, ret);
	PQfreemem(buffer);
	return result_str;
}

#get_last_result ⇒ PGresult

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.

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

Returns:



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# File 'ext/pg.c', line 2620

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


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

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

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

	if (prev) {
		rb_pgresult = new_pgresult(prev, conn);
		pgresult_check(self, rb_pgresult);
	}

	return rb_pgresult;
}

#get_result ⇒ PGresult #get_result {|pg_result| ... } ⇒ Object

Blocks waiting for the next result from a call to PGconn#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 PGresult object will automatically be cleared when the block terminates. In this instance, conn.exec returns the value of the block.

Overloads:

  • #get_result ⇒ PGresult

    Returns:

  • #get_result {|pg_result| ... } ⇒ Object

    Yields:

    • (pg_result) 


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# File 'ext/pg.c', line 1810

static VALUE
pgconn_get_result(VALUE self)
{
	PGconn *conn = get_pgconn(self);
	PGresult *result;
	VALUE rb_pgresult;

	result = PQgetResult(conn);
	if(result == NULL)
		return Qnil;
	rb_pgresult = new_pgresult(result, conn);
	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, rb_pgresult,
			pgresult_clear, rb_pgresult);
	}
	return rb_pgresult;
}

#host ⇒ Object

Returns the connected server name.



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# File 'ext/pg.c', line 647

static VALUE
pgconn_host(VALUE self)
{
	char *host = PQhost(get_pgconn(self));
	if (!host) return Qnil;
	return rb_tainted_str_new2(host);
}

#internal_encoding ⇒ Encoding

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) 


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# File 'ext/pg.c', line 3842

static VALUE
pgconn_internal_encoding(VALUE self)
{
	return rb_enc_from_encoding(pgconn_get_client_encoding_as_rb_encoding(get_pgconn(self)));
}

#internal_encoding=(value) ⇒ Object

A wrapper of PGconn#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 ‘SQL_ASCII’ to the client_encoding.



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# File 'ext/pg.c', line 3862

static VALUE
pgconn_internal_encoding_set(VALUE self, VALUE enc)
{
	if (NIL_P(enc)) {
		pgconn_set_client_encoding(self, rb_usascii_str_new_cstr("SQL_ASCII"));
		return enc;
	}
	else if (TYPE(enc) == T_STRING && strcasecmp("JOHAB", RSTRING_PTR(enc)) == 0) {
		pgconn_set_client_encoding(self, rb_usascii_str_new_cstr("JOHAB"));
		return enc;
	}
	else {
		int i;
		const char *name; 
		name = rb_enc_name(rb_to_encoding(enc));

		/* sequential search becuase rarely called */
		for (i = 0; i < sizeof(enc_pg2ruby_mapping)/sizeof(enc_pg2ruby_mapping[0]); ++i) {
			if (strcmp(name, enc_pg2ruby_mapping[i][1]) == 0) {
				if (PQsetClientEncoding(get_pgconn(self), enc_pg2ruby_mapping[i][0]) == -1) {
					VALUE server_encoding = pgconn_external_encoding(self);
					rb_raise(rb_eEncCompatError, "imcompatible character encodings: %s and %s",
							rb_enc_name(rb_to_encoding(server_encoding)),
							enc_pg2ruby_mapping[i][0]);
				}
				return enc;
			}
		}

		/* Ruby 1.9.1 does not support JOHAB */
		if (strcasecmp(name, "JOHAB") == 0) {
			pgconn_set_client_encoding(self, rb_usascii_str_new_cstr("JOHAB"));
			return enc;
		}
	}

	enc = rb_inspect(enc);
	rb_raise(rb_ePGError, "unknown encoding: %s", StringValuePtr(enc));
}

#is_busy ⇒ Boolean

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

Returns:

  • (Boolean) 


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# File 'ext/pg.c', line 1858

static VALUE
pgconn_is_busy(self)
VALUE self;

#isnonblocking ⇒ Boolean Also known as: nonblocking?

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

Returns:

  • (Boolean) 


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# File 'ext/pg.c', line 1911

static VALUE
pgconn_isnonblocking(self)
VALUE self;

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

Closes the postgres large object of lo_desc.

Returns:

  • (nil) 


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# File 'ext/pg.c', line 2943

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

	if(lo_close(conn,lo_desc) < 0)
		rb_raise(rb_ePGError,"lo_close failed");

	return Qnil;
}

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

Creates a large object with mode mode. Returns a large object Oid. On failure, it raises PGError exception.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 2690

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

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

	lo_oid = lo_creat(conn, mode);
	if (lo_oid == 0)
		rb_raise(rb_ePGError, "lo_creat failed");

	return INT2FIX(lo_oid);
}

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

Creates a large object with oid oid. Returns the large object Oid. On failure, it raises PGError exception.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 2717

static VALUE
pgconn_locreate(VALUE self, VALUE in_lo_oid)
{
	Oid ret, lo_oid;
	PGconn *conn = get_pgconn(self);
	lo_oid = NUM2INT(in_lo_oid);

	ret = lo_create(conn, in_lo_oid);
	if (ret == InvalidOid)
		rb_raise(rb_ePGError, "lo_create failed");

	return INT2FIX(ret);
}

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

Saves a large object of oid to a file.

Returns:

  • (nil) 


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# File 'ext/pg.c', line 2761

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

	oid = NUM2INT(lo_oid);
	if (oid < 0) {
		rb_raise(rb_ePGError, "invalid large object oid %d",oid);
	}

	if (lo_export(conn, oid, StringValuePtr(filename)) < 0) {
		rb_raise(rb_ePGError, "%s", PQerrorMessage(conn));
	}
	return Qnil;
}

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

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

On failure, it raises a PGError exception.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 2739

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

	PGconn *conn = get_pgconn(self);

	Check_Type(filename, T_STRING);

	lo_oid = lo_import(conn, StringValuePtr(filename));
	if (lo_oid == 0) {
		rb_raise(rb_ePGError, "%s", PQerrorMessage(conn));
	}
	return INT2FIX(lo_oid);
}

#lo_lseek(lo_desc, offset, whence) ⇒ Fixnum 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:

  • (Fixnum) 


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# File 'ext/pg.c', line 2885

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

	if((ret = lo_lseek(conn, lo_desc, NUM2INT(offset), NUM2INT(whence))) < 0) {
		rb_raise(rb_ePGError, "lo_lseek failed");
	}

	return INT2FIX(ret);
}

#lo_open(oid, [mode]) ⇒ Fixnum 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:

  • (Fixnum) 


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# File 'ext/pg.c', line 2789

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

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

	if((fd = lo_open(conn, lo_oid, mode)) < 0) {
		rb_raise(rb_ePGError, "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) 


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# File 'ext/pg.c', line 2844

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

  buffer = ALLOC_N(char, len);
	if(buffer == NULL)
		rb_raise(rb_eNoMemError, "ALLOC failed!");

	if (len < 0){
		rb_raise(rb_ePGError,"nagative length %d given", len);
	}

	if((ret = lo_read(conn, lo_desc, buffer, len)) < 0)
		rb_raise(rb_ePGError, "lo_read failed");

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

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

	return str;
}

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

Returns the current position of the large object lo_desc.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 2905

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

	if((position = lo_tell(conn, lo_desc)) < 0)
		rb_raise(rb_ePGError,"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) 


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# File 'ext/pg.c', line 2924

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

	if(lo_truncate(conn,lo_desc,len) < 0)
		rb_raise(rb_ePGError,"lo_truncate failed");

	return Qnil;
}

#lo_unlink(oid) ⇒ nil Also known as: lounlink

Unlinks (deletes) the postgres large object of oid.

Returns:

  • (nil) 


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# File 'ext/pg.c', line 2961

static VALUE
pgconn_lounlink(VALUE self, VALUE in_oid)
{
	PGconn *conn = get_pgconn(self);
	int oid = NUM2INT(in_oid);

	if (oid < 0)
		rb_raise(rb_ePGError, "invalid oid %d",oid);

	if(lo_unlink(conn,oid) < 0)
		rb_raise(rb_ePGError,"lo_unlink failed");

	return Qnil;
}

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

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

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 2817

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

	Check_Type(buffer, T_STRING);

	if( RSTRING_LEN(buffer) < 0) {
		rb_raise(rb_ePGError, "write buffer zero string");
	}
	if((n = lo_write(conn, fd, StringValuePtr(buffer), 
				RSTRING_LEN(buffer))) < 0) {
		rb_raise(rb_ePGError, "lo_write failed: %s", PQerrorMessage(conn));
	}

	return INT2FIX(n);
}

#make_empty_pgresult(status) ⇒ PGresult

Constructs and empty PGresult 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

Returns:



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# File 'ext/pg.c', line 1272

static VALUE
pgconn_make_empty_pgresult(VALUE self, VALUE status)
{
	PGresult *result;
	VALUE rb_pgresult;
	PGconn *conn = get_pgconn(self);
	result = PQmakeEmptyPGresult(conn, NUM2INT(status));
	rb_pgresult = new_pgresult(result, conn);
	pgresult_check(self, rb_pgresult);
	return rb_pgresult;
}

#notifies ⇒ Object

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



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# File 'ext/pg.c', line 1988

static VALUE
pgconn_notifies(VALUE self)
{
	PGconn* conn = get_pgconn(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 = PQnotifies(conn);
	if (notification == NULL) {
		return Qnil;
	}

	hash = rb_hash_new();
	relname = rb_tainted_str_new2(notification->relname);
	be_pid = INT2NUM(notification->be_pid);
	extra = rb_tainted_str_new2(PGNOTIFY_EXTRA(notification));

	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;
}

#options ⇒ Object

Returns backend option string.



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# File 'ext/pg.c', line 688

static VALUE
pgconn_options(VALUE self)
{
	char *options = PQoptions(get_pgconn(self));
	if (!options) return Qnil;
	return rb_tainted_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) 


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# File 'ext/pg.c', line 743

static VALUE
pgconn_parameter_status(VALUE self, VALUE param_name)
{
	const char *ret = PQparameterStatus(get_pgconn(self), 
			StringValuePtr(param_name));
	if(ret == NULL)
		return Qnil;
	else
		return rb_tainted_str_new2(ret);
}

#pass ⇒ Object

Returns the authenticated user name.



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# File 'ext/pg.c', line 633

static VALUE
pgconn_pass(VALUE self)
{
	char *user = PQpass(get_pgconn(self));
	if (!user) return Qnil;
	return rb_tainted_str_new2(user);
}

#port ⇒ Object

Returns the connected server port number.



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# File 'ext/pg.c', line 661

static VALUE
pgconn_port(VALUE self)
{
	char* port = PQport(get_pgconn(self));
	return INT2NUM(atol(port));
}

#prepare(stmt_name, sql[, param_types ]) ⇒ PGresult

Prepares statement sql with name name to be executed later. Returns a PGresult instance on success. On failure, it raises a PGError exception.

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, $1, $2, etc., inside the SQL query.

Returns:



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# File 'ext/pg.c', line 1034

static VALUE
pgconn_prepare(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE name, command, in_paramtypes;
	VALUE param;
	int i = 0;
	int nParams = 0;
	Oid *paramTypes = NULL;

	rb_scan_args(argc, argv, "21", &name, &command, &in_paramtypes);
	Check_Type(name, T_STRING);
	Check_Type(command, T_STRING);

	if(! NIL_P(in_paramtypes)) {
		Check_Type(in_paramtypes, T_ARRAY);
		nParams = RARRAY_LEN(in_paramtypes);
		paramTypes = ALLOC_N(Oid, nParams); 
		for(i = 0; i < nParams; i++) {
			param = rb_ary_entry(in_paramtypes, i);
			Check_Type(param, T_FIXNUM);
			if(param == Qnil)
				paramTypes[i] = 0;
			else
				paramTypes[i] = NUM2INT(param);
		}
	}
	result = PQprepare(conn, StringValuePtr(name), StringValuePtr(command),
			nParams, paramTypes);

	xfree(paramTypes);

	rb_pgresult = new_pgresult(result, conn);
	pgresult_check(self, rb_pgresult);
	return rb_pgresult;
}

#protocol_version ⇒ Integer

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) 


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# File 'ext/pg.c', line 762

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

#put_copy_data(buffer) ⇒ 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).

Raises an exception if an error occurs.

Returns:

  • (Boolean) 


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# File 'ext/pg.c', line 2147

static VALUE
pgconn_put_copy_data(self, buffer)
VALUE self, buffer;

#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).

Returns:

  • (Boolean) 


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# File 'ext/pg.c', line 2180

static VALUE
pgconn_put_copy_end(int argc, VALUE *argv, VALUE self)
{
	VALUE str;
	VALUE error;
	int ret;
	char *error_message = NULL;
	PGconn *conn = get_pgconn(self);

	if (rb_scan_args(argc, argv, "01", &str) == 0)
		error_message = NULL;
	else
		error_message = StringValuePtr(str);

	ret = PQputCopyEnd(conn, error_message);
	if(ret == -1) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return (ret) ? Qtrue : Qfalse;
}

#quote_ident(str) ⇒ String #quote_ident(str) ⇒ 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 PGconn.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.

Overloads:

  • #quote_ident(str) ⇒ String

    Returns:

    • (String)
  • #quote_ident(str) ⇒ String

    Returns:

    • (String) 


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# File 'ext/pg.c', line 2507

static VALUE
pgconn_s_quote_ident(VALUE self, VALUE in_str)
{
	VALUE ret;
	char *str = StringValuePtr(in_str);
	/* result size at most NAMEDATALEN*2 plus surrounding
	 * double-quotes. */
	char buffer[NAMEDATALEN*2+2];
	unsigned int i=0,j=0;

	if(strlen(str) >= NAMEDATALEN) {
		rb_raise(rb_eArgError, 
			"Input string is longer than NAMEDATALEN-1 (%d)",
			NAMEDATALEN-1);
	}
	buffer[j++] = '"';
	for(i = 0; i < strlen(str) && str[i]; i++) {
		if(str[i] == '"') 
			buffer[j++] = '"';
		buffer[j++] = str[i];
	}
	buffer[j++] = '"';
	ret = rb_str_new(buffer,j);
	OBJ_INFECT(ret, in_str);
	return ret;
}

#reset ⇒ Object

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



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# File 'ext/pg.c', line 558

static VALUE
pgconn_reset(VALUE self)
{
	PQreset(get_pgconn(self));
	return self;
}

#reset_poll ⇒ Fixnum

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

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 591

static VALUE
pgconn_reset_poll(VALUE self)
{
	PostgresPollingStatusType status;
	status = PQresetPoll(get_pgconn(self));
	return INT2FIX((int)status);
}

#reset_start ⇒ nil

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

Returns:

  • (nil) 


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# File 'ext/pg.c', line 575

static VALUE
pgconn_reset_start(VALUE self)
{
	if(PQresetStart(get_pgconn(self)) == 0)
		rb_raise(rb_ePGError, "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) 


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# File 'ext/pg.c', line 1779

static VALUE
pgconn_send_describe_portal(VALUE self, VALUE portal)
{
	VALUE error;
	PGconn *conn = get_pgconn(self);
	/* returns 0 on failure */
	if(PQsendDescribePortal(conn,StringValuePtr(portal)) == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	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) 


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# File 'ext/pg.c', line 1757

static VALUE
pgconn_send_describe_prepared(VALUE self, VALUE stmt_name)
{
	VALUE error;
	PGconn *conn = get_pgconn(self);
	/* returns 0 on failure */
	if(PQsendDescribePrepared(conn,StringValuePtr(stmt_name)) == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	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 PGError exception.

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, $1, $2, etc., inside the SQL query.

Returns:

  • (nil) 


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# File 'ext/pg.c', line 1585

static VALUE
pgconn_send_prepare(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	int result;
	VALUE name, command, in_paramtypes;
	VALUE param;
	VALUE error;
	int i = 0;
	int nParams = 0;
	Oid *paramTypes = NULL;

	rb_scan_args(argc, argv, "21", &name, &command, &in_paramtypes);
	Check_Type(name, T_STRING);
	Check_Type(command, T_STRING);

	if(! NIL_P(in_paramtypes)) {
		Check_Type(in_paramtypes, T_ARRAY);
		nParams = RARRAY_LEN(in_paramtypes);
		paramTypes = ALLOC_N(Oid, nParams); 
		for(i = 0; i < nParams; i++) {
			param = rb_ary_entry(in_paramtypes, i);
			Check_Type(param, T_FIXNUM);
			if(param == Qnil)
				paramTypes[i] = 0;
			else
				paramTypes[i] = NUM2INT(param);
		}
	}
	result = PQsendPrepare(conn, StringValuePtr(name), StringValuePtr(command),
			nParams, paramTypes);

	xfree(paramTypes);

	if(result == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

#send_query(sql[, params, result_format ]) ⇒ nil

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

params is an optional 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   => Fixnum (oid of type of bind parameter)
   :format => Fixnum (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, $1, $2, 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.

Returns:

  • (nil) 


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# File 'ext/pg.c', line 1450

static VALUE
pgconn_send_query(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	int result;
	VALUE command, params, in_res_fmt;
	VALUE param, param_type, param_value, param_format;
	VALUE param_value_tmp;
	VALUE sym_type, sym_value, sym_format;
	VALUE gc_array;
	VALUE error;
	int i=0;
	int nParams;
	Oid *paramTypes;
	char ** paramValues;
	int *paramLengths;
	int *paramFormats;
	int resultFormat;

	rb_scan_args(argc, argv, "12", &command, &params, &in_res_fmt);
	Check_Type(command, T_STRING);

	/* If called with no parameters, use PQsendQuery */
	if(NIL_P(params)) {
		if(PQsendQuery(conn,StringValuePtr(command)) == 0) {
			error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
			rb_iv_set(error, "@connection", self);
			rb_exc_raise(error);
		}
		return Qnil;
	}

	/* If called with parameters, and optionally result_format,
	 * use PQsendQueryParams
	 */
	Check_Type(params, T_ARRAY);

	if(NIL_P(in_res_fmt)) {
		resultFormat = 0;
	}
	else {
		resultFormat = NUM2INT(in_res_fmt);
	}

	gc_array = rb_ary_new();
	rb_gc_register_address(&gc_array);
	sym_type = ID2SYM(rb_intern("type"));
	sym_value = ID2SYM(rb_intern("value"));
	sym_format = ID2SYM(rb_intern("format"));
	nParams = RARRAY_LEN(params);
	paramTypes = ALLOC_N(Oid, nParams); 
	paramValues = ALLOC_N(char *, nParams);
	paramLengths = ALLOC_N(int, nParams);
	paramFormats = ALLOC_N(int, nParams);
	for(i = 0; i < nParams; i++) {
		param = rb_ary_entry(params, i);
		if (TYPE(param) == T_HASH) {
			param_type = rb_hash_aref(param, sym_type);
			param_value_tmp = rb_hash_aref(param, sym_value);
			if(param_value_tmp == Qnil)
				param_value = param_value_tmp;
			else
				param_value = rb_obj_as_string(param_value_tmp);
			param_format = rb_hash_aref(param, sym_format);
		}
		else {
			param_type = INT2NUM(0);
			if(param == Qnil)
				param_value = param;
			else
				param_value = rb_obj_as_string(param);
			param_format = INT2NUM(0);
		}

		if(param_type == Qnil)
			paramTypes[i] = 0;
		else
			paramTypes[i] = NUM2INT(param_type);

		if(param_value == Qnil) {
			paramValues[i] = NULL;
			paramLengths[i] = 0;
		}
		else {
			Check_Type(param_value, T_STRING);
			/* make sure param_value doesn't get freed by the GC */
			rb_ary_push(gc_array, param_value);
			paramValues[i] = StringValuePtr(param_value);
			paramLengths[i] = RSTRING_LEN(param_value);
		}

		if(param_format == Qnil)
			paramFormats[i] = 0;
		else
			paramFormats[i] = NUM2INT(param_format);
	}

	result = PQsendQueryParams(conn, StringValuePtr(command), nParams, paramTypes, 
		(const char * const *)paramValues, paramLengths, paramFormats, resultFormat);

	rb_gc_unregister_address(&gc_array);	

	xfree(paramTypes);
	xfree(paramValues);
	xfree(paramLengths);
	xfree(paramFormats);

	if(result == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

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

Execute prepared named statement specified by statement_name asynchronously, and returns immediately. On failure, it raises a PGError exception.

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 => Fixnum (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, $1, $2, 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.



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# File 'ext/pg.c', line 1652

static VALUE
pgconn_send_query_prepared(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	int result;
	VALUE name, params, in_res_fmt;
	VALUE param, param_value, param_format;
	VALUE param_value_tmp;
	VALUE sym_value, sym_format;
	VALUE gc_array;
	VALUE error;
	int i = 0;
	int nParams;
	char ** paramValues;
	int *paramLengths;
	int *paramFormats;
	int resultFormat;

	rb_scan_args(argc, argv, "12", &name, &params, &in_res_fmt);
	Check_Type(name, T_STRING);

	if(NIL_P(params)) {
		params = rb_ary_new2(0);
		resultFormat = 0;
	}
	else {
		Check_Type(params, T_ARRAY);
	}

	if(NIL_P(in_res_fmt)) {
		resultFormat = 0;
	}
	else {
		resultFormat = NUM2INT(in_res_fmt);
	}

	gc_array = rb_ary_new();
	rb_gc_register_address(&gc_array);
	sym_value = ID2SYM(rb_intern("value"));
	sym_format = ID2SYM(rb_intern("format"));
	nParams = RARRAY_LEN(params);
	paramValues = ALLOC_N(char *, nParams);
	paramLengths = ALLOC_N(int, nParams);
	paramFormats = ALLOC_N(int, nParams);
	for(i = 0; i < nParams; i++) {
		param = rb_ary_entry(params, i);
		if (TYPE(param) == T_HASH) {
			param_value_tmp = rb_hash_aref(param, sym_value);
			if(param_value_tmp == Qnil)
				param_value = param_value_tmp;
			else
				param_value = rb_obj_as_string(param_value_tmp);
			param_format = rb_hash_aref(param, sym_format);
		}
		else {
			if(param == Qnil)
				param_value = param;
			else
				param_value = rb_obj_as_string(param);
			param_format = INT2NUM(0);
		}

		if(param_value == Qnil) {
			paramValues[i] = NULL;
			paramLengths[i] = 0;
		}
		else {
			Check_Type(param_value, T_STRING);
			/* make sure param_value doesn't get freed by the GC */
			rb_ary_push(gc_array, param_value);
			paramValues[i] = StringValuePtr(param_value);
			paramLengths[i] = RSTRING_LEN(param_value);
		}

		if(param_format == Qnil)
			paramFormats[i] = 0;
		else
			paramFormats[i] = NUM2INT(param_format);
	}

	result = PQsendQueryPrepared(conn, StringValuePtr(name), nParams, 
		(const char * const *)paramValues, paramLengths, paramFormats, 
		resultFormat);

	rb_gc_unregister_address(&gc_array);

	xfree(paramValues);
	xfree(paramLengths);
	xfree(paramFormats);

	if(result == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

#server_version ⇒ Integer

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) 


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# File 'ext/pg.c', line 779

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

#set_client_encoding(encoding) ⇒ Object

Sets the client encoding to the encoding String.



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# File 'ext/pg.c', line 2434

static VALUE
pgconn_set_client_encoding(VALUE self, VALUE str)
{
	Check_Type(str, T_STRING);
	if ((PQsetClientEncoding(get_pgconn(self), StringValuePtr(str))) == -1){
		rb_raise(rb_ePGError, "invalid encoding name: %s",StringValuePtr(str));
	}
	return Qnil;
}

#set_error_verbosity(verbosity) ⇒ Fixnum

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

  • PQERRORS_TERSE

  • PQERRORS_DEFAULT

  • PQERRORS_VERBOSE

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 2255

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

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

This function takes a new block to act as the handler, which should accept a single parameter that will be a PGresult 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.

Yields:

  • (message)

Returns:

  • (Proc) 


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# File 'ext/pg.c', line 2388

static VALUE
pgconn_set_notice_processor(VALUE self)
{
	VALUE proc, old_proc;
	PGconn *conn = get_pgconn(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(default_notice_processor == NULL)
		default_notice_processor = PQsetNoticeProcessor(conn, NULL, NULL);

	old_proc = rb_iv_get(self, "@notice_processor");
	if( rb_block_given_p() ) {
		proc = rb_block_proc();
		PQsetNoticeProcessor(conn, notice_processor_proxy, (void *)self);
	} else {
		/* if no block is given, set back to default */
		proc = Qnil;
		PQsetNoticeProcessor(conn, default_notice_processor, NULL);
	}

	rb_iv_set(self, "@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.

This function takes a new block to act as the handler, which should accept a single parameter that will be a PGresult 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.

Yields:

  • (result)

Returns:

  • (Proc) 


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# File 'ext/pg.c', line 2342

static VALUE
pgconn_set_notice_receiver(VALUE self)
{
	VALUE proc, old_proc;
	PGconn *conn = get_pgconn(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(default_notice_receiver == NULL)
		default_notice_receiver = PQsetNoticeReceiver(conn, NULL, NULL);

	old_proc = rb_iv_get(self, "@notice_receiver");
	if( rb_block_given_p() ) {
		proc = rb_block_proc();
		PQsetNoticeReceiver(conn, notice_receiver_proxy, (void *)self);
	} else {
		/* if no block is given, set back to default */
		proc = Qnil;
		PQsetNoticeReceiver(conn, default_notice_receiver, NULL);
	}

	rb_iv_set(self, "@notice_receiver", proc);
	return old_proc;
}

#setnonblocking(Boolean) ⇒ nil

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

Returns:

  • (nil) 


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# File 'ext/pg.c', line 1881

static VALUE
pgconn_setnonblocking(self, state)
VALUE self, state;

#socket ⇒ Fixnum

Returns the socket’s file descriptor for this connection.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 805

static VALUE
pgconn_socket(VALUE self)
{
	int sd;
	if( (sd = PQsocket(get_pgconn(self))) < 0)
		rb_raise(rb_ePGError, "Can't get socket descriptor");
	return INT2NUM(sd);
}

#status ⇒ Object

Returns status of connection : CONNECTION_OK or CONNECTION_BAD



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# File 'ext/pg.c', line 702

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

#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) 


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# File 'ext/pg.c', line 2272

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

	if(rb_respond_to(stream,rb_intern("fileno")) == Qfalse)
		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_iv_set(self, "@trace_stream", new_file);

	PQtrace(get_pgconn(self), new_fp);
	return Qnil;
}

#transaction {|conn| ... } ⇒ nil

Executes a BEGIN at the start of the block, and a COMMIT at the end of the block, or ROLLBACK if any exception occurs.

Yields:

  • (conn)

Returns:

  • (nil) 


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# File 'ext/pg.c', line 2452

static VALUE
pgconn_transaction(VALUE self)
{
	PGconn *conn = get_pgconn(self);
	PGresult *result;
	VALUE rb_pgresult;
	int status;

	if (rb_block_given_p()) {
		result = PQexec(conn, "BEGIN");
		rb_pgresult = new_pgresult(result, conn);
		pgresult_check(self, rb_pgresult);
		rb_protect(rb_yield, self, &status);
		if(status == 0) {
			result = PQexec(conn, "COMMIT");
			rb_pgresult = new_pgresult(result, conn);
			pgresult_check(self, rb_pgresult);
		}
		else {
			/* exception occurred, ROLLBACK and re-raise */
			result = PQexec(conn, "ROLLBACK");
			rb_pgresult = new_pgresult(result, conn);
			pgresult_check(self, rb_pgresult);
			rb_jump_tag(status);
		}

	}
	else {
		/* no block supplied? */
		rb_raise(rb_eArgError, "Must supply block for PGconn#transaction");
	}
	return Qnil;
}

#transaction_status ⇒ Object

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)



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# File 'ext/pg.c', line 719

static VALUE
pgconn_transaction_status(VALUE self)
{
	return INT2NUM(PQtransactionStatus(get_pgconn(self)));
}

#tty ⇒ Object

Returns the connected pgtty. (Obsolete)



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# File 'ext/pg.c', line 674

static VALUE
pgconn_tty(VALUE self)
{
	char *tty = PQtty(get_pgconn(self));
	if (!tty) return Qnil;
	return rb_tainted_str_new2(tty);
}

#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.



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# File 'ext/pg.c', line 1401

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

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

	to = PQunescapeBytea(from, &to_len);

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

#untrace ⇒ nil

Disables the message tracing.

Returns:

  • (nil) 


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# File 'ext/pg.c', line 2313

static VALUE
pgconn_untrace(VALUE self)
{
	VALUE trace_stream;
	PQuntrace(get_pgconn(self));
	trace_stream = rb_iv_get(self, "@trace_stream");
	rb_funcall(trace_stream, rb_intern("close"), 0);
	rb_iv_set(self, "@trace_stream", Qnil);
	return Qnil;
}

#user ⇒ Object

Returns the authenticated user name.



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# File 'ext/pg.c', line 619

static VALUE
pgconn_user(VALUE self)
{
	char *user = PQuser(get_pgconn(self));
	if (!user) return Qnil;
	return rb_tainted_str_new2(user);
}

#wait_for_notify([ timeout ]) ⇒ String #wait_for_notify([ timeout ]) {|event, pid| ... } ⇒ Object 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 and the generating pid into the block.

Overloads:

  • #wait_for_notify([ timeout ]) ⇒ String

    Returns:

    • (String)
  • #wait_for_notify([ timeout ]) {|event, pid| ... } ⇒ Object

    Yields:

    • (event, pid) 


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# File 'ext/pg.c', line 2069

static VALUE
pgconn_wait_for_notify(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn( self );
	PGnotify *notification;
	int sd = PQsocket( conn );
	int ret;
	struct timeval timeout;
	struct timeval *ptimeout = NULL;
	VALUE timeout_in, relname = Qnil, be_pid = Qnil, extra = Qnil;
	double timeout_sec;
	fd_set sd_rset;
#ifdef _WIN32
	fd_set crt_sd_rset;
#endif

	if ( sd < 0 )
		rb_bug( "PQsocket(conn): couldn't fetch the connection's socket!" );

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

	/* Check for notifications */
	while ( (notification = PQnotifies(conn)) == NULL ) {
		FD_ZERO( &sd_rset );
		FD_SET( sd, &sd_rset );

#ifdef _WIN32
		create_crt_fd(&sd_rset, &crt_sd_rset);
#endif

		/* Wait for the socket to become readable before checking again */
		ret = rb_thread_select( sd+1, &sd_rset, NULL, NULL, ptimeout );

#ifdef _WIN32
		cleanup_crt_fd(&sd_rset, &crt_sd_rset);
#endif

		if ( ret < 0 )
			rb_sys_fail( 0 );

		/* Return nil if the select timed out */
		if ( ret == 0 ) return Qnil;

		/* Read the socket */
		if ( (ret = PQconsumeInput(conn)) != 1 )
			rb_raise( rb_ePGError, "PQconsumeInput == %d: %s", ret, PQerrorMessage(conn) );
	}

	relname = rb_tainted_str_new2( notification->relname );
	be_pid = INT2NUM( notification->be_pid );
#ifdef HAVE_ST_NOTIFY_EXTRA
	extra = rb_str_new2( notification->extra );
#endif
	PQfreemem( notification );

	if ( rb_block_given_p() )
		rb_yield_values( 3, relname, be_pid, extra );

	return relname;
}