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.

Constant Summary

CONNECT_ARGUMENT_ORDER =

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

%w[host port options tty dbname user password]

Constants included from Constants

PG::Constants::CONNECTION_AUTH_OK, PG::Constants::CONNECTION_AWAITING_RESPONSE, PG::Constants::CONNECTION_BAD, 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::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_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_CONTEXT, 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_SEVERITY, 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::PQERRORS_DEFAULT, 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::PQTRANS_ACTIVE, PG::Constants::PQTRANS_IDLE, PG::Constants::PQTRANS_INERROR, PG::Constants::PQTRANS_INTRANS, PG::Constants::PQTRANS_UNKNOWN, PG::Constants::SEEK_CUR, PG::Constants::SEEK_END, PG::Constants::SEEK_SET

Class Method Summary (collapse)

Instance Method Summary (collapse)

Constructor Details

- (Object) initialize

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.

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
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 )

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.



177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
# File 'ext/pg_connection.c', line 177

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

	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
	pgconn_set_default_encoding( self );
#endif

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

Class Method Details

+ (Array) PG::Connection.conndefaults

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)


311
312
313
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 311

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

	UNUSED( self );

	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;
}

+ (Object) 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)

This is an asynchronous version of PG::Connection.connect().

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, or include the 'options' connection parameter.



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
# File 'ext/pg_connection.c', line 225

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

	/*
	 * 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 );
	conninfo = rb_funcall2( klass, rb_intern("parse_connect_args"), argc, argv );
	conn     = PQconnectStart( StringValuePtr(conninfo) );

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

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

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

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

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

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)


354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
# File 'ext/pg_connection.c', line 354

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

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

	return rval;
}

+ (String) escape_bytea(string)

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.

Returns:

  • (String)


1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
# File 'ext/pg_connection.c', line 1369

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(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);
	OBJ_INFECT(ret, str);
	PQfreemem(to);
	return ret;
}

+ (String) escape_string(str)

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.

Returns:

  • (String)


1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
# File 'ext/pg_connection.c', line 1305

static VALUE
pgconn_s_escape(VALUE self, VALUE string)
{
	char *escaped;
	size_t size;
	int 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(pg_get_pgconn(self), escaped,
			RSTRING_PTR(string), RSTRING_LEN(string), &error);
		if(error) {
			xfree(escaped);
			rb_raise(rb_ePGerror, "%s", PQerrorMessage(pg_get_pgconn(self)));
		}
	} else {
		size = PQescapeString(escaped, RSTRING_PTR(string), (int)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 = pg_conn_enc_get( pg_get_pgconn(self) );
	} else {
		enc = rb_enc_get(string);
	}
	rb_enc_associate(result, enc);
#endif

	return result;
}

+ (Object) parse_connect_args(*args)

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



34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
# File 'lib/pg/connection.rb', line 34

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().

	# Parameter 'fallback_application_name' was introduced in PostgreSQL 9.0
	# together with PQescapeLiteral().
	if PG::Connection.instance_methods.find{|m| m.to_sym == :escape_literal }
		appname = $0.sub(/^(.{30}).{4,}(.{30})$/){ $1+"..."+$2 }
		appname = PG::Connection.quote_connstr( appname )
		connopts = ["fallback_application_name=#{appname}"]
	else
		connopts = []
	end

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

	return connopts.join(' ')
end

+ (Fixnum) PG::Connection.ping(connection_hash) + (Fixnum) PG::Connection.ping(connection_string) + (Fixnum) PG::Connection.ping(host, port, options, tty, dbname, login, password)

Check server status.

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)

Overloads:

  • + (Fixnum) PG::Connection.ping(connection_hash)

    Returns:

    • (Fixnum)
  • + (Fixnum) PG::Connection.ping(connection_string)

    Returns:

    • (Fixnum)
  • + (Fixnum) PG::Connection.ping(host, port, options, tty, dbname, login, password)

    Returns:

    • (Fixnum)


278
279
280
281
282
283
284
285
286
287
288
# File 'ext/pg_connection.c', line 278

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

	conninfo = rb_funcall2( klass, rb_intern("parse_connect_args"), argc, argv );
	ping     = PQping( StringValuePtr(conninfo) );

	return INT2FIX((int)ping);
}

+ (Object) quote_connstr(value)

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



27
28
29
# File 'lib/pg/connection.rb', line 27

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

+ (String) PG::Connection.quote_ident(str) + (String) quote_ident(str)

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 PG::Connection.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:

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

    Returns:

    • (String)
  • + (String) quote_ident(str)

    Returns:

    • (String)


2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
# File 'ext/pg_connection.c', line 2826

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;

	UNUSED( self );

	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;
}

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

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.



1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
# File 'ext/pg_connection.c', line 1402

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*)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

- (Fixnum) backend_pid

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

Returns:

  • (Fixnum)


783
784
785
786
787
# File 'ext/pg_connection.c', line 783

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

- (Boolean) block([ timeout ])

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)


2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
# File 'ext/pg_connection.c', line 2876

static VALUE
pgconn_block( int argc, VALUE *argv, VALUE self ) {
	PGconn *conn = pg_get_pgconn( self );

	/* If WIN32 and Ruby 1.9 do not use rb_thread_select() which sometimes hangs
	 * and does not wait (nor sleep) any time even if timeout is given.
	 * Instead use the Winsock events and rb_w32_wait_events(). */

	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( conn, ptimeout, get_result_readable);

	if( !ret )
		return Qfalse;

	return Qtrue;
}

- (String) cancel

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)


2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
# File 'ext/pg_connection.c', line 2078

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

	cancel = PQgetCancel(pg_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
}

- (Array) PG::Connection.conndefaults

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)


311
312
313
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 311

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

	UNUSED( self );

	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;
}

- (Fixnum) connect_poll

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 = PG::Connection.connect_start("dbname=mydatabase")
socket = conn.socket_io
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)
    if(not select([socket], [], [], 10.0))
      raise "Asynchronous connection timed out!"
    end
  elsif(status == PG::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)


414
415
416
417
418
419
420
# File 'ext/pg_connection.c', line 414

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

- (Boolean) connection_needs_password

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

Returns:

  • (Boolean)


796
797
798
799
800
# File 'ext/pg_connection.c', line 796

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

- (Boolean) connection_used_password

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

Returns:

  • (Boolean)


809
810
811
812
813
# File 'ext/pg_connection.c', line 809

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

- (Object) consume_input

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.



1960
1961
1962
# File 'ext/pg_connection.c', line 1960

static VALUE
pgconn_consume_input(self)
VALUE self;

- (Object) db

Returns the connected database name.



508
509
510
511
512
513
514
# File 'ext/pg_connection.c', line 508

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

- (PG::Result) describe_portal(portal_name)

Retrieve information about the portal portal_name.

Returns:



1237
1238
1239
# File 'ext/pg_connection.c', line 1237

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

- (PG::Result) describe_prepared(statement_name)

Retrieve information about the prepared statement statement_name.

Returns:



1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
# File 'ext/pg_connection.c', line 1210

static VALUE
pgconn_describe_prepared(VALUE self, VALUE stmt_name)
{
	PGresult *result;
	VALUE rb_pgresult;
	PGconn *conn = pg_get_pgconn(self);
	char *stmt;
	if(stmt_name == Qnil) {
		stmt = NULL;
	}
	else {
		Check_Type(stmt_name, T_STRING);
		stmt = StringValuePtr(stmt_name);
	}
	result = gvl_PQdescribePrepared(conn, stmt);
	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);
	return rb_pgresult;
}

- (String) error_message

Returns the error message about connection.

Returns:

  • (String)


693
694
695
696
697
698
699
# File 'ext/pg_connection.c', line 693

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

- (String) escape_bytea(string)

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.

Returns:

  • (String)


1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
# File 'ext/pg_connection.c', line 1369

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(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);
	OBJ_INFECT(ret, str);
	PQfreemem(to);
	return ret;
}

- (String) escape_identifier(str)

Escape an arbitrary String str as an identifier.

Returns:

  • (String)


1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
# File 'ext/pg_connection.c', line 1462

static VALUE
pgconn_escape_identifier(VALUE self, VALUE string)
{
	PGconn *conn = pg_get_pgconn(self);
	char *escaped = NULL;
	VALUE error;
	VALUE result = Qnil;

	Check_Type(string, T_STRING);

	escaped = PQescapeIdentifier(conn, RSTRING_PTR(string), RSTRING_LEN(string));
	if (escaped == NULL)
	{
		error = rb_exc_new2(rb_ePGerror, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
		return Qnil;
	}
	result = rb_str_new2(escaped);
	PQfreemem(escaped);
	OBJ_INFECT(result, string);

	return result;
}

- (String) escape_literal(str)

Escape an arbitrary String str as a literal.

Returns:

  • (String)


1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
# File 'ext/pg_connection.c', line 1429

static VALUE
pgconn_escape_literal(VALUE self, VALUE string)
{
	PGconn *conn = pg_get_pgconn(self);
	char *escaped = NULL;
	VALUE error;
	VALUE result = Qnil;

	Check_Type(string, T_STRING);

	escaped = PQescapeLiteral(conn, RSTRING_PTR(string), RSTRING_LEN(string));
	if (escaped == NULL)
	{
		error = rb_exc_new2(rb_ePGerror, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
		return Qnil;
	}
	result = rb_str_new2(escaped);
	PQfreemem(escaped);
	OBJ_INFECT(result, string);

	return result;
}

- (String) escape_string(str) 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.

Returns:

  • (String)


1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
# File 'ext/pg_connection.c', line 1305

static VALUE
pgconn_s_escape(VALUE self, VALUE string)
{
	char *escaped;
	size_t size;
	int 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(pg_get_pgconn(self), escaped,
			RSTRING_PTR(string), RSTRING_LEN(string), &error);
		if(error) {
			xfree(escaped);
			rb_raise(rb_ePGerror, "%s", PQerrorMessage(pg_get_pgconn(self)));
		}
	} else {
		size = PQescapeString(escaped, RSTRING_PTR(string), (int)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 = pg_conn_enc_get( pg_get_pgconn(self) );
	} else {
		enc = rb_enc_get(string);
	}
	rb_enc_associate(result, enc);
#endif

	return result;
}

- (PG::Result) exec(sql) - (Object) exec(sql) {|pg_result| ... } Also known as: query, async_exec

Sends SQL query request specified by sql to PostgreSQL. Returns a PG::Result instance on success. 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.

Overloads:

  • - (PG::Result) exec(sql)

    Returns:

  • - (Object) exec(sql) {|pg_result| ... }

    Yields:

    • (pg_result)


838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
# File 'ext/pg_connection.c', line 838

static VALUE
pgconn_exec(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	PGresult *result = NULL;
	VALUE rb_pgresult;

	/* If called with no parameters, use PQexec */
	if ( argc == 1 ) {
		Check_Type(argv[0], T_STRING);

		result = gvl_PQexec(conn, StringValuePtr(argv[0]));
		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;
	}

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

}

- (PG::Result) exec_params(sql, params[, result_format ]) - (Object) exec_params(sql, params[, result_format ]) {|pg_result| ... }

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   => 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 PG::Result object will automatically be cleared when the block terminates. In this instance, conn.exec returns the value of the block.

Overloads:

  • - (PG::Result) exec_params(sql, params[, result_format ])

    Returns:

  • - (Object) exec_params(sql, params[, result_format ]) {|pg_result| ... }

    Yields:

    • (pg_result)


903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
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
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
# File 'ext/pg_connection.c', line 903

static VALUE
pgconn_exec_params( int argc, VALUE *argv, VALUE self )
{
	PGconn *conn = pg_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);

	/*
	 * Handle the edge-case where the caller is coming from #exec, but passed an explict +nil+
	 * for the second parameter.
	 */
	if ( NIL_P(params) ) {
		return pgconn_exec( 1, argv, self );
		}

	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 = (int)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] = (int)RSTRING_LEN(param_value);
		}

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

	result = gvl_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 = 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::Result) exec_prepared(statement_name[, params, result_format ]) - (Object) exec_prepared(statement_name[, params, result_format ]) {|pg_result| ... }

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 => 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 PG::Result object will automatically be cleared when the block terminates. In this instance, conn.exec_prepared returns the value of the block.

Overloads:

  • - (PG::Result) exec_prepared(statement_name[, params, result_format ])

    Returns:

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

    Yields:

    • (pg_result)


1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
# File 'ext/pg_connection.c', line 1104

static VALUE
pgconn_exec_prepared(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = pg_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 = (int)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] = (int)RSTRING_LEN(param_value);
		}

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

	result = gvl_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 = 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;
}

- (Encoding) external_encoding

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)


3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
# File 'ext/pg_connection.c', line 3360

static VALUE
pgconn_external_encoding(VALUE self)
{
	PGconn *conn = pg_get_pgconn( self );
	VALUE encoding = rb_iv_get( self, "@external_encoding" );
	rb_encoding *enc = NULL;
	const char *pg_encname = NULL;

	/* Use cached value if found */
	if ( RTEST(encoding) ) return encoding;

	pg_encname = PQparameterStatus( conn, "server_encoding" );
	enc = pg_get_pg_encname_as_rb_encoding( pg_encname );
	encoding = rb_enc_from_encoding( enc );

	rb_iv_set( self, "@external_encoding", encoding );

	return encoding;
}

- (Object) finish Also known as: close

Closes the backend connection.



428
429
430
431
432
433
434
435
# File 'ext/pg_connection.c', line 428

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

- (Boolean) finished?

Returns true if the backend connection has been closed.

Returns:

  • (Boolean)

Returns:

  • (Boolean)


444
445
446
447
448
449
# File 'ext/pg_connection.c', line 444

static VALUE
pgconn_finished_p( VALUE self )
{
	if ( DATA_PTR(self) ) return Qfalse;
	return Qtrue;
}

- (Boolean) flush

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 PG::Error if some other failure occurred.

Returns:

  • (Boolean)


2052
2053
2054
# File 'ext/pg_connection.c', line 2052

static VALUE
pgconn_flush(self)
VALUE self;

- (String) get_client_encoding

Returns the client encoding as a String.

Returns:

  • (String)


2734
2735
2736
2737
2738
2739
# File 'ext/pg_connection.c', line 2734

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

- (String) get_copy_data([ async = false ])

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)


2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
# File 'ext/pg_connection.c', line 2471

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 = pg_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 = gvl_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;
}

- (PG::Result) 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.

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

Returns:



2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
# File 'ext/pg_connection.c', line 2920

static VALUE
pgconn_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)
			break;
	}

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

	return rb_pgresult;
}

- (PG::Result) get_result - (Object) get_result {|pg_result| ... }

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.

Overloads:

  • - (PG::Result) get_result

    Returns:

  • - (Object) get_result {|pg_result| ... }

    Yields:

    • (pg_result)


1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
# File 'ext/pg_connection.c', line 1934

static VALUE
pgconn_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;
}

- (Object) host

Returns the connected server name.



550
551
552
553
554
555
556
# File 'ext/pg_connection.c', line 550

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

- (Encoding) internal_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)


3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
# File 'ext/pg_connection.c', line 3296

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;
	}
}

- (Object) internal_encoding=(value)

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.



3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
# File 'ext/pg_connection.c', line 3323

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 {
		rb_encoding *rbenc = rb_to_encoding( enc );
		const char *name = pg_get_rb_encoding_as_pg_encoding( rbenc );

		if ( 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 );
		}
		return enc;
	}

	rb_raise( rb_ePGerror, "unknown encoding: %s", RSTRING_PTR(rb_inspect(enc)) );

	return Qnil;
}

- (Boolean) is_busy

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

Returns:

  • (Boolean)


1982
1983
1984
# File 'ext/pg_connection.c', line 1982

static VALUE
pgconn_is_busy(self)
VALUE self;

- (Boolean) isnonblocking Also known as: nonblocking?

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

Returns:

  • (Boolean)


2035
2036
2037
# File 'ext/pg_connection.c', line 2035

static VALUE
pgconn_isnonblocking(self)
VALUE self;

- (nil) lo_close(lo_desc) Also known as: loclose

Closes the postgres large object of lo_desc.

Returns:

  • (nil)


3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
# File 'ext/pg_connection.c', line 3250

static VALUE
pgconn_loclose(VALUE self, VALUE in_lo_desc)
{
	PGconn *conn = pg_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;
}

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

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

Returns:

  • (Fixnum)


2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
# File 'ext/pg_connection.c', line 2997

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);

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

	return INT2FIX(lo_oid);
}

- (Fixnum) lo_create(oid) Also known as: locreate

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

Returns:

  • (Fixnum)


3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
# File 'ext/pg_connection.c', line 3024

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

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

	return INT2FIX(ret);
}

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

Saves a large object of oid to a file.

Returns:

  • (nil)


3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
# File 'ext/pg_connection.c', line 3068

static VALUE
pgconn_loexport(VALUE self, VALUE lo_oid, VALUE filename)
{
	PGconn *conn = pg_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;
}

- (Fixnum) lo_import(file) Also known as: loimport

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

On failure, it raises a PG::Error.

Returns:

  • (Fixnum)


3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
# File 'ext/pg_connection.c', line 3046

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

	PGconn *conn = pg_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);
}

- (Fixnum) lo_lseek(lo_desc, offset, whence) 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)


3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
# File 'ext/pg_connection.c', line 3192

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;

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

	return INT2FIX(ret);
}

- (Fixnum) lo_open(oid, [mode]) 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)


3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
# File 'ext/pg_connection.c', line 3096

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 = 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);
}

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

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

Returns:

  • (String)


3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
# File 'ext/pg_connection.c', line 3151

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;

  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;
}

- (Fixnum) lo_tell(lo_desc) Also known as: lotell

Returns the current position of the large object lo_desc.

Returns:

  • (Fixnum)


3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
# File 'ext/pg_connection.c', line 3212

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);

	if((position = lo_tell(conn, lo_desc)) < 0)
		rb_raise(rb_ePGerror,"lo_tell failed");

	return INT2FIX(position);
}

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

Truncates the large object lo_desc to size len.

Returns:

  • (nil)


3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
# File 'ext/pg_connection.c', line 3231

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);

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

	return Qnil;
}

Unlinks (deletes) the postgres large object of oid.

Returns:

  • (nil)


3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
# File 'ext/pg_connection.c', line 3268

static VALUE
pgconn_lounlink(VALUE self, VALUE in_oid)
{
	PGconn *conn = pg_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;
}

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

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

Returns:

  • (Fixnum)


3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
# File 'ext/pg_connection.c', line 3124

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) {
		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);
}

- (PG::Result) make_empty_pgresult(status)

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

Returns:



1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
# File 'ext/pg_connection.c', line 1275

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;
}

- (Object) notifies

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



2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
# File 'ext/pg_connection.c', line 2112

static VALUE
pgconn_notifies(VALUE self)
{
	PGconn* conn = pg_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(notification->extra);
#ifdef M17N_SUPPORTED
	ENCODING_SET( relname, rb_enc_to_index(pg_conn_enc_get( conn )) );
	ENCODING_SET( extra, rb_enc_to_index(pg_conn_enc_get( conn )) );
#endif

	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;
}

- (Object) options

Returns backend option string.



591
592
593
594
595
596
597
# File 'ext/pg_connection.c', line 591

static VALUE
pgconn_options(VALUE self)
{
	char *options = PQoptions(pg_get_pgconn(self));
	if (!options) return Qnil;
	return rb_tainted_str_new2(options);
}

- (String) parameter_status(param_name)

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)


646
647
648
649
650
651
652
653
654
# File 'ext/pg_connection.c', line 646

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

- (Object) pass

Returns the authenticated user name.



536
537
538
539
540
541
542
# File 'ext/pg_connection.c', line 536

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

- (Object) port

Returns the connected server port number.



564
565
566
567
568
569
# File 'ext/pg_connection.c', line 564

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

- (PG::Result) prepare(stmt_name, sql[, param_types ])

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

Returns:



1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
# File 'ext/pg_connection.c', line 1036

static VALUE
pgconn_prepare(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = pg_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 = (int)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 = gvl_PQprepare(conn, StringValuePtr(name), StringValuePtr(command),
			nParams, paramTypes);

	xfree(paramTypes);

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

- (Integer) protocol_version

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)


664
665
666
667
668
# File 'ext/pg_connection.c', line 664

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

- (Boolean) put_copy_data(buffer)

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)


2407
2408
2409
# File 'ext/pg_connection.c', line 2407

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

- (Boolean) put_copy_end([ error_message ])

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)


2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
# File 'ext/pg_connection.c', line 2439

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

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

	ret = gvl_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;
}

- (String) PG::Connection.quote_ident(str) - (String) quote_ident(str)

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 PG::Connection.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:

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

    Returns:

    • (String)
  • - (String) quote_ident(str)

    Returns:

    • (String)


2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
# File 'ext/pg_connection.c', line 2826

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;

	UNUSED( self );

	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;
}

- (Object) reset

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



459
460
461
462
463
464
465
# File 'ext/pg_connection.c', line 459

static VALUE
pgconn_reset( VALUE self )
{
	pgconn_close_socket_io( self );
	PQreset( pg_get_pgconn(self) );
	return self;
}

- (Fixnum) reset_poll

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

Returns:

  • (Fixnum)


494
495
496
497
498
499
500
# File 'ext/pg_connection.c', line 494

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

- (nil) reset_start

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)


477
478
479
480
481
482
483
484
# File 'ext/pg_connection.c', line 477

static VALUE
pgconn_reset_start(VALUE self)
{
	pgconn_close_socket_io( self );
	if(PQresetStart(pg_get_pgconn(self)) == 0)
		rb_raise(rb_ePGerror, "reset has failed");
	return Qnil;
}

- (nil) send_describe_portal(portal_name)

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

Returns:

  • (nil)


1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
# File 'ext/pg_connection.c', line 1903

static VALUE
pgconn_send_describe_portal(VALUE self, VALUE portal)
{
	VALUE error;
	PGconn *conn = pg_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;
}

- (nil) send_describe_prepared(statement_name)

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

Returns:

  • (nil)


1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
# File 'ext/pg_connection.c', line 1881

static VALUE
pgconn_send_describe_prepared(VALUE self, VALUE stmt_name)
{
	VALUE error;
	PGconn *conn = pg_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;
}

- (nil) send_prepare(stmt_name, sql[, param_types ])

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

Returns:

  • (nil)


1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
# File 'ext/pg_connection.c', line 1709

static VALUE
pgconn_send_prepare(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = pg_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 = (int)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;
}

- (nil) send_query(sql[, params, result_format ])

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 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)


1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
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
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
# File 'ext/pg_connection.c', line 1574

static VALUE
pgconn_send_query(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = pg_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 = (int)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] = (int)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;
}

- (Object) send_query_prepared(statement_name[, params, result_format ]) - (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 => 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.



1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
# File 'ext/pg_connection.c', line 1776

static VALUE
pgconn_send_query_prepared(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = pg_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 = (int)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] = (int)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;
}

- (Integer) server_version

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)


681
682
683
684
685
# File 'ext/pg_connection.c', line 681

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

- (Object) set_client_encoding(encoding) Also known as: client_encoding=

Sets the client encoding to the encoding String.



2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
# File 'ext/pg_connection.c', line 2748

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

	Check_Type(str, T_STRING);

	if ( (PQsetClientEncoding(conn, StringValuePtr(str))) == -1 ) {
		rb_raise(rb_ePGerror, "invalid encoding name: %s",StringValuePtr(str));
	}

	return Qnil;
}

- (Encoding) set_default_encoding

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)


3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
# File 'ext/pg_connection.c', line 3390

static VALUE
pgconn_set_default_encoding( VALUE self )
{
	PGconn *conn = pg_get_pgconn( self );
	rb_encoding *enc;
	const char *encname;

	if (( enc = rb_default_internal_encoding() )) {
		encname = pg_get_rb_encoding_as_pg_encoding( enc );
		if ( PQsetClientEncoding(conn, encname) != 0 )
			rb_warn( "Failed to set the default_internal encoding to %s: '%s'",
			         encname, PQerrorMessage(conn) );
		return rb_enc_from_encoding( enc );
	} else {
		return Qnil;
	}
}

- (Fixnum) set_error_verbosity(verbosity)

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

  • PQERRORS_TERSE

  • PQERRORS_DEFAULT

  • PQERRORS_VERBOSE

Returns:

  • (Fixnum)


2514
2515
2516
2517
2518
2519
2520
# File 'ext/pg_connection.c', line 2514

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));
}

- (Proc) set_notice_processor {|message| ... }

See #set_notice_receiver for the desription 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)


2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
# File 'ext/pg_connection.c', line 2699

static VALUE
pgconn_set_notice_processor(VALUE self)
{
	VALUE proc, old_proc;
	PGconn *conn = pg_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, gvl_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;
}

- (Proc) set_notice_receiver {|result| ... }

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)


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
# File 'ext/pg_connection.c', line 2635

static VALUE
pgconn_set_notice_receiver(VALUE self)
{
	VALUE proc, old_proc;
	PGconn *conn = pg_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, gvl_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;
}

- (self) set_single_row_mode

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 row 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)


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

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

	if( PQsetSingleRowMode(conn) == 0 )
	{
		error = rb_exc_new2(rb_ePGerror, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}

	return self;
}

- (nil) setnonblocking(Boolean)

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.

Returns:

  • (nil)


2005
2006
2007
# File 'ext/pg_connection.c', line 2005

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

- (Fixnum) socket

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 really usable, since it can not be used to build a Ruby IO object.

Returns:

  • (Fixnum)


716
717
718
719
720
721
722
723
# File 'ext/pg_connection.c', line 716

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

- (Object) socket_io

Fetch a memoized IO object created from the Connection's underlying socket. This object can be used for IO.select to wait for events while running asynchronous API calls.

Using this instead of #socket 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.

This method can also be used on Windows but requires Ruby-2.0+.



742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
# File 'ext/pg_connection.c', line 742

static VALUE
pgconn_socket_io(VALUE self)
{
	int sd;
	int ruby_sd;
	ID id_autoclose = rb_intern("autoclose=");
	VALUE socket_io = rb_iv_get( self, "@socket_io" );

	if ( !RTEST(socket_io) ) {
		if( (sd = PQsocket(pg_get_pgconn(self))) < 0)
			rb_raise(rb_ePGerror, "Can't get socket descriptor");

		#ifdef _WIN32
			ruby_sd = rb_w32_wrap_io_handle((HANDLE)(intptr_t)sd, O_RDWR|O_BINARY|O_NOINHERIT);
		#else
			ruby_sd = sd;
		#endif

		socket_io = rb_funcall( rb_cIO, rb_intern("for_fd"), 1, INT2NUM(ruby_sd) );

		/* Disable autoclose feature, when supported */
		if( rb_respond_to(socket_io, id_autoclose) ){
			rb_funcall( socket_io, id_autoclose, 1, Qfalse );
		}

		rb_iv_set( self, "@socket_io", socket_io );
	}

	return socket_io;
}

- (Object) status

Returns status of connection : CONNECTION_OK or CONNECTION_BAD



605
606
607
608
609
# File 'ext/pg_connection.c', line 605

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

- (nil) trace(stream)

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)


2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
# File 'ext/pg_connection.c', line 2531

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(pg_get_pgconn(self), new_fp);
	return Qnil;
}

- (nil) transaction {|conn| ... }

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)


2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
# File 'ext/pg_connection.c', line 2770

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

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

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

- (Object) transaction_status

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)


622
623
624
625
626
# File 'ext/pg_connection.c', line 622

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

- (Object) tty

Returns the connected pgtty. (Obsolete)



577
578
579
580
581
582
583
# File 'ext/pg_connection.c', line 577

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

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

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.



1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
# File 'ext/pg_connection.c', line 1402

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*)StringValuePtr(str);

	to = PQunescapeBytea(from, &to_len);

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

- (nil) untrace

Disables the message tracing.

Returns:

  • (nil)


2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
# File 'ext/pg_connection.c', line 2572

static VALUE
pgconn_untrace(VALUE self)
{
	VALUE trace_stream;
	PQuntrace(pg_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;
}

- (Object) user

Returns the authenticated user name.



522
523
524
525
526
527
528
# File 'ext/pg_connection.c', line 522

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

- (String) wait_for_notify([ timeout ]) - (Object) wait_for_notify([ timeout ]) {|event, pid| ... } - (Object) wait_for_notify([ timeout ]) 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.

Under PostgreSQL 9.0 and later, if the notification is sent with the optional payload string, it will be given to the block as the third argument.

Overloads:

  • - (String) wait_for_notify([ timeout ])

    Returns:

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

    Yields:

    • (event, pid)


2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
# File 'ext/pg_connection.c', line 2350

static VALUE
pgconn_wait_for_notify(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = pg_get_pgconn( 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( conn, ptimeout, notify_readable);

	/* Return nil if the select timed out */
	if ( !pnotification ) return Qnil;

	relname = rb_tainted_str_new2( pnotification->relname );
#ifdef M17N_SUPPORTED
	ENCODING_SET( relname, rb_enc_to_index(pg_conn_enc_get( conn )) );
#endif
	be_pid = INT2NUM( pnotification->be_pid );
#ifdef HAVE_ST_NOTIFY_EXTRA
	if ( *pnotification->extra ) {
		extra = rb_tainted_str_new2( pnotification->extra );
#ifdef M17N_SUPPORTED
		ENCODING_SET( extra, rb_enc_to_index(pg_conn_enc_get( conn )) );
#endif
	}
#endif
	PQfreemem( pnotification );

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

	return relname;
}