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_COLUMN_NAME, PG::Constants::PG_DIAG_CONSTRAINT_NAME, PG::Constants::PG_DIAG_CONTEXT, PG::Constants::PG_DIAG_DATATYPE_NAME, PG::Constants::PG_DIAG_INTERNAL_POSITION, PG::Constants::PG_DIAG_INTERNAL_QUERY, PG::Constants::PG_DIAG_MESSAGE_DETAIL, PG::Constants::PG_DIAG_MESSAGE_HINT, PG::Constants::PG_DIAG_MESSAGE_PRIMARY, PG::Constants::PG_DIAG_SCHEMA_NAME, PG::Constants::PG_DIAG_SEVERITY, PG::Constants::PG_DIAG_SOURCE_FILE, PG::Constants::PG_DIAG_SOURCE_FUNCTION, PG::Constants::PG_DIAG_SOURCE_LINE, PG::Constants::PG_DIAG_SQLSTATE, PG::Constants::PG_DIAG_STATEMENT_POSITION, PG::Constants::PG_DIAG_TABLE_NAME, PG::Constants::PQERRORS_DEFAULT, PG::Constants::PQERRORS_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

#initializeObject

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.



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
208
209
210
211
# File 'ext/pg_connection.c', line 181

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 = gvl_PQconnectdb(StringValuePtr(conninfo));

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

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

	if (PQstatus(conn) == CONNECTION_BAD) {
		error = rb_exc_new2(rb_eConnectionBad, 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

.conndefaultsObject

call-seq:

PG::Connection.conndefaults() -> Array

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

:keyword

the name of the option

:envvar

the environment variable to fall back to

:compiled

the compiled in option as a secondary fallback

:val

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

:label

the label for the field

:dispchar

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

:dispsize

field size



318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
# File 'ext/pg_connection.c', line 318

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;
}

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

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



229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
# File 'ext/pg_connection.c', line 229

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     = gvl_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_eConnectionBad, 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;
}

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

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

Return value is the encrypted password.



361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
# File 'ext/pg_connection.c', line 361

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;
}

.escape_bytea(string) ⇒ 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.



1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
# File 'ext/pg_connection.c', line 1384

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;
}

.escape_string(str) ⇒ String

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.



1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
# File 'ext/pg_connection.c', line 1320

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;
}

.parse_connect_args(*args) ⇒ Object

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

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

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)



282
283
284
285
286
287
288
289
290
291
292
# File 'ext/pg_connection.c', line 282

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);
}

.quote_connstr(value) ⇒ Object

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

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

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

For example, in a typical SQL query: SELECT FOO FROM MYTABLE The identifier FOO is folded to lower case, so it actually means foo. If you really want to access the case-sensitive field name FOO, use this function like 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.



2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
# File 'ext/pg_connection.c', line 2889

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;
#ifdef M17N_SUPPORTED
	rb_encoding* enc;
#endif

	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);

#ifdef M17N_SUPPORTED
	if ( rb_obj_class(self) == rb_cPGconn ) {
		enc = pg_conn_enc_get( pg_get_pgconn(self) );
	} else {
		enc = rb_enc_get(in_str);
	}
	rb_enc_associate(ret, enc);
#endif

	return ret;
}

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

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



1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
# File 'ext/pg_connection.c', line 1417

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

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

This function has the same behavior as #exec, but is implemented using the asynchronous command processing API of libpq.

Overloads:

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

    Yields:

    • (pg_result)


3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
# File 'ext/pg_connection.c', line 3033

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

	/* remove any remaining results from the queue */
	pgconn_block( 0, NULL, self ); /* wait for input (without blocking) before reading the last result */
	pgconn_get_last_result( self );

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

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

#backend_pidFixnum

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



791
792
793
794
795
# File 'ext/pg_connection.c', line 791

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

#block([ timeout ]) ⇒ Boolean

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

Returns false if timeout is reached, true otherwise.

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



2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
# File 'ext/pg_connection.c', line 2952

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;
}

#cancelString

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.



2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
# File 'ext/pg_connection.c', line 2104

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

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

#conndefaultsObject

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



171
172
173
# File 'lib/pg/connection.rb', line 171

def conndefaults
	return self.class.conndefaults
end

#connect_pollFixnum

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.


421
422
423
424
425
426
427
# File 'ext/pg_connection.c', line 421

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

#connection_needs_passwordBoolean

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



804
805
806
807
808
# File 'ext/pg_connection.c', line 804

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

#connection_used_passwordBoolean

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



817
818
819
820
821
# File 'ext/pg_connection.c', line 817

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

#consume_inputObject

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



1986
1987
1988
# File 'ext/pg_connection.c', line 1986

static VALUE
pgconn_consume_input(self)
VALUE self;

#copy_data(sql) ⇒ Object

call-seq:

conn.copy_data( sql ) {|sql_result| ... } -> PG::Result

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

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

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

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

Example with CSV input format:

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

This creates my_table and inserts two rows.

Example with CSV output format:

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

This prints all rows of my_table to stdout:

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


119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
# File 'lib/pg/connection.rb', line 119

def copy_data( sql )
	res = exec( sql )

	case res.result_status
	when PGRES_COPY_IN
		begin
			yield res
		rescue Exception => err
			errmsg = "%s while copy data: %s" % [ err.class.name, err.message ]
			put_copy_end( errmsg )
			get_result
			raise
		else
			put_copy_end
			get_last_result
		end

	when PGRES_COPY_OUT
		begin
			yield res
		rescue Exception => err
			cancel
			while get_copy_data
			end
			while get_result
			end
			raise
		else
			res = get_last_result
			if res.result_status != PGRES_COMMAND_OK
				while get_copy_data
				end
				while get_result
				end
				raise PG::NotAllCopyDataRetrieved, "Not all COPY data retrieved"
			end
			res
		end

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

#dbObject

Returns the connected database name.



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

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

#describe_portal(portal_name) ⇒ PG::Result

Retrieve information about the portal portal_name.



1252
1253
1254
# File 'ext/pg_connection.c', line 1252

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

#describe_prepared(statement_name) ⇒ PG::Result

Retrieve information about the prepared statement statement_name.



1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
# File 'ext/pg_connection.c', line 1225

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;
}

#error_messageString

Returns the error message about connection.



701
702
703
704
705
706
707
# File 'ext/pg_connection.c', line 701

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

#escape_bytea(string) ⇒ 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.



1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
# File 'ext/pg_connection.c', line 1384

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;
}

#escape_identifier(str) ⇒ String

Escape an arbitrary String str as an identifier.

This method does the same as #quote_ident, but uses libpq to process the string.



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

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);

#ifdef M17N_SUPPORTED
	rb_enc_associate(result, pg_conn_enc_get( pg_get_pgconn(self) ));
#endif

	return result;
}

#escape_literal(str) ⇒ String

Escape an arbitrary String str as a literal.



1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
# File 'ext/pg_connection.c', line 1444

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);

#ifdef M17N_SUPPORTED
	rb_enc_associate(result, pg_conn_enc_get( pg_get_pgconn(self) ));
#endif

	return result;
}

#escape_string(str) ⇒ String 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.



1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
# File 'ext/pg_connection.c', line 1320

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;
}

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

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.

#exec is implemented on the synchronous command processing API of libpq, whereas #async_exec is implemented on the asynchronous API. #exec is somewhat faster that #async_exec, but blocks any signals to be processed until the query is finished. This is most notably visible by a delayed reaction to Control+C. Both methods ensure that other threads can process while waiting for the server to complete the request.

Overloads:

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

    Yields:

    • (pg_result)


853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
# File 'ext/pg_connection.c', line 853

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 );
	}

}

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

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:

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

    Yields:

    • (pg_result)


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
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
# File 'ext/pg_connection.c', line 918

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;
}

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

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:

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

    Yields:

    • (pg_result)


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
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
# File 'ext/pg_connection.c', line 1119

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;
}

#external_encodingEncoding

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



3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
# File 'ext/pg_connection.c', line 3426

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;
}

#finishObject Also known as: close

Closes the backend connection.



435
436
437
438
439
440
441
442
# File 'ext/pg_connection.c', line 435

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

#finished?Boolean

Returns true if the backend connection has been closed.



451
452
453
454
455
456
# File 'ext/pg_connection.c', line 451

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

#flushBoolean

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.



2078
2079
2080
# File 'ext/pg_connection.c', line 2078

static VALUE
pgconn_flush(self)
VALUE self;

#get_client_encodingString

Returns the client encoding as a String.



2796
2797
2798
2799
2800
2801
# File 'ext/pg_connection.c', line 2796

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);
}

#get_copy_data([ async = false ]) ⇒ String

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

See also #copy_data.



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 2533

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;
}

#get_last_resultPG::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.



2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
# File 'ext/pg_connection.c', line 2996

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;
}

#get_resultPG::Result #get_result {|pg_result| ... } ⇒ Object

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:

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

    Yields:

    • (pg_result)


1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
# File 'ext/pg_connection.c', line 1960

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;
}

#hostObject

Returns the connected server name.



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

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

#internal_encodingEncoding

defined in Ruby 1.9 or later.

Returns:

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

  • nil - the client_encoding is 'SQL_ASCII'



3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
# File 'ext/pg_connection.c', line 3362

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

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

#internal_encoding=(value) ⇒ Object

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

value can be one of:

  • an Encoding

  • a String - a name of Encoding

  • nil - sets the client_encoding to SQL_ASCII.



3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
# File 'ext/pg_connection.c', line 3389

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;
}

#is_busyBoolean

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



2008
2009
2010
# File 'ext/pg_connection.c', line 2008

static VALUE
pgconn_is_busy(self)
VALUE self;

#isnonblockingBoolean Also known as: nonblocking?

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



2061
2062
2063
# File 'ext/pg_connection.c', line 2061

static VALUE
pgconn_isnonblocking(self)
VALUE self;

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

Closes the postgres large object of lo_desc.



3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
# File 'ext/pg_connection.c', line 3316

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;
}

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

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



3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
# File 'ext/pg_connection.c', line 3063

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);
}

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

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



3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
# File 'ext/pg_connection.c', line 3090

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);
}

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

Saves a large object of oid to a file.



3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
# File 'ext/pg_connection.c', line 3134

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;
}

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

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

On failure, it raises a PG::Error.



3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
# File 'ext/pg_connection.c', line 3112

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);
}

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

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



3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
# File 'ext/pg_connection.c', line 3258

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);
}

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

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

If mode is omitted, the default is INV_READ.



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 3162

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);
}

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

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



3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
# File 'ext/pg_connection.c', line 3217

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;
}

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

Returns the current position of the large object lo_desc.



3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
# File 'ext/pg_connection.c', line 3278

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);
}

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

Truncates the large object lo_desc to size len.



3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
# File 'ext/pg_connection.c', line 3297

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.



3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
# File 'ext/pg_connection.c', line 3334

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;
}

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

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



3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
# File 'ext/pg_connection.c', line 3190

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);
}

#make_empty_pgresult(status) ⇒ PG::Result

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

  • PGRES_EMPTY_QUERY

  • PGRES_COMMAND_OK

  • PGRES_TUPLES_OK

  • PGRES_COPY_OUT

  • PGRES_COPY_IN

  • PGRES_BAD_RESPONSE

  • PGRES_NONFATAL_ERROR

  • PGRES_FATAL_ERROR

  • PGRES_COPY_BOTH



1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
# File 'ext/pg_connection.c', line 1290

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

#notifiesObject

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



2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
# File 'ext/pg_connection.c', line 2138

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 = gvl_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;
}

#optionsObject

Returns backend option string.



599
600
601
602
603
604
605
# File 'ext/pg_connection.c', line 599

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

#parameter_status(param_name) ⇒ String

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

  • server_version

  • server_encoding

  • client_encoding

  • is_superuser

  • session_authorization

  • DateStyle

  • TimeZone

  • integer_datetimes

  • standard_conforming_strings

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



654
655
656
657
658
659
660
661
662
# File 'ext/pg_connection.c', line 654

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);
}

#passObject

Returns the authenticated user name.



544
545
546
547
548
549
550
# File 'ext/pg_connection.c', line 544

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

#portObject

Returns the connected server port number.



572
573
574
575
576
577
# File 'ext/pg_connection.c', line 572

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

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

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.



1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
# File 'ext/pg_connection.c', line 1051

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;
}

#protocol_versionInteger

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



672
673
674
675
676
# File 'ext/pg_connection.c', line 672

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

#put_copy_data(buffer) ⇒ Boolean

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

Raises an exception if an error occurs.

See also #copy_data.



2467
2468
2469
# File 'ext/pg_connection.c', line 2467

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

#put_copy_end([ error_message ]) ⇒ Boolean

Sends end-of-data indication to the server.

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

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



2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
# File 'ext/pg_connection.c', line 2499

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;
}

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

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

For example, in a typical SQL query: SELECT FOO FROM MYTABLE The identifier FOO is folded to lower case, so it actually means foo. If you really want to access the case-sensitive field name FOO, use this function like 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.



2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
# File 'ext/pg_connection.c', line 2889

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;
#ifdef M17N_SUPPORTED
	rb_encoding* enc;
#endif

	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);

#ifdef M17N_SUPPORTED
	if ( rb_obj_class(self) == rb_cPGconn ) {
		enc = pg_conn_enc_get( pg_get_pgconn(self) );
	} else {
		enc = rb_enc_get(in_str);
	}
	rb_enc_associate(ret, enc);
#endif

	return ret;
}

#resetObject

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



466
467
468
469
470
471
472
# File 'ext/pg_connection.c', line 466

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

#reset_pollFixnum

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



501
502
503
504
505
506
507
# File 'ext/pg_connection.c', line 501

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

#reset_startnil

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



484
485
486
487
488
489
490
491
# File 'ext/pg_connection.c', line 484

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

#send_describe_portal(portal_name) ⇒ nil

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



1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
# File 'ext/pg_connection.c', line 1929

static VALUE
pgconn_send_describe_portal(VALUE self, VALUE portal)
{
	VALUE error;
	PGconn *conn = pg_get_pgconn(self);
	/* returns 0 on failure */
	if(gvl_PQsendDescribePortal(conn,StringValuePtr(portal)) == 0) {
		error = rb_exc_new2(rb_eUnableToSend, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

#send_describe_prepared(statement_name) ⇒ nil

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



1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
# File 'ext/pg_connection.c', line 1907

static VALUE
pgconn_send_describe_prepared(VALUE self, VALUE stmt_name)
{
	VALUE error;
	PGconn *conn = pg_get_pgconn(self);
	/* returns 0 on failure */
	if(gvl_PQsendDescribePrepared(conn,StringValuePtr(stmt_name)) == 0) {
		error = rb_exc_new2(rb_eUnableToSend, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

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

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



1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
# File 'ext/pg_connection.c', line 1735

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 = gvl_PQsendPrepare(conn, StringValuePtr(name), StringValuePtr(command),
			nParams, paramTypes);

	xfree(paramTypes);

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

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

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



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
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
# File 'ext/pg_connection.c', line 1600

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(gvl_PQsendQuery(conn,StringValuePtr(command)) == 0) {
			error = rb_exc_new2(rb_eUnableToSend, 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 = gvl_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_eUnableToSend, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

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

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



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
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
# File 'ext/pg_connection.c', line 1802

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 = gvl_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_eUnableToSend, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

#server_versionInteger

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



689
690
691
692
693
# File 'ext/pg_connection.c', line 689

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

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

Sets the client encoding to the encoding String.



2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
# File 'ext/pg_connection.c', line 2810

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;
}

#set_default_encodingEncoding

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



3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
# File 'ext/pg_connection.c', line 3456

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;
	}
}

#set_error_verbosity(verbosity) ⇒ Fixnum

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

  • PQERRORS_TERSE

  • PQERRORS_DEFAULT

  • PQERRORS_VERBOSE



2576
2577
2578
2579
2580
2581
2582
# File 'ext/pg_connection.c', line 2576

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

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

See #set_notice_receiver for the 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)


2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
# File 'ext/pg_connection.c', line 2761

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;
}

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

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

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

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

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

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

Yields:

  • (result)


2697
2698
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
# File 'ext/pg_connection.c', line 2697

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;
}

#set_single_row_modeself

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

Each (but the last) received Result has exactly one row and a Result#result_status of PGRES_SINGLE_TUPLE. The last 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


1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
# File 'ext/pg_connection.c', line 1552

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;
}

#setnonblocking(Boolean) ⇒ nil

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



2031
2032
2033
# File 'ext/pg_connection.c', line 2031

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

#socketFixnum

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.



724
725
726
727
728
729
730
731
# File 'ext/pg_connection.c', line 724

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

#socket_ioObject

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+.



750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
# File 'ext/pg_connection.c', line 750

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_eConnectionBad, "PQsocket() can't get socket descriptor");

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

#statusObject

Returns status of connection : CONNECTION_OK or CONNECTION_BAD



613
614
615
616
617
# File 'ext/pg_connection.c', line 613

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

#trace(stream) ⇒ nil

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



2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
# File 'ext/pg_connection.c', line 2593

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;
}

#transaction {|conn| ... } ⇒ Object

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)


2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
# File 'ext/pg_connection.c', line 2832

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

	if (rb_block_given_p()) {
		result = gvl_PQexec(conn, "BEGIN");
		rb_pgresult = pg_new_result(result, self);
		pg_result_check(rb_pgresult);
		block_result = 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 block_result;
}

#transaction_statusObject

returns one of the following statuses:

PQTRANS_IDLE    = 0 (connection idle)
PQTRANS_ACTIVE  = 1 (command in progress)
PQTRANS_INTRANS = 2 (idle, within transaction block)
PQTRANS_INERROR = 3 (idle, within failed transaction)
PQTRANS_UNKNOWN = 4 (cannot determine status)


630
631
632
633
634
# File 'ext/pg_connection.c', line 630

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

#ttyObject

Returns the connected pgtty. (Obsolete)



585
586
587
588
589
590
591
# File 'ext/pg_connection.c', line 585

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

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

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



1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
# File 'ext/pg_connection.c', line 1417

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;
}

#untracenil

Disables the message tracing.



2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
# File 'ext/pg_connection.c', line 2634

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;
}

#userObject

Returns the authenticated user name.



530
531
532
533
534
535
536
# File 'ext/pg_connection.c', line 530

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

#wait_for_notify([ timeout ]) ⇒ String #wait_for_notify([ timeout ]) {|event, pid| ... } ⇒ Object #wait_for_notify([ timeout ]) ⇒ Object Also known as: notifies_wait

Blocks while waiting for notification(s), or until the optional timeout is reached, whichever comes first. timeout is measured in seconds and can be fractional.

Returns nil if timeout is reached, the name of the NOTIFY event otherwise. If used in block form, passes the name of the NOTIFY event and the generating pid into the block.

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:

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

    Yields:

    • (event, pid)


2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
# File 'ext/pg_connection.c', line 2407

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;
}