class PG::Connection
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.
Constants
- CONNECT_ARGUMENT_ORDER
The order the options are passed to the ::connect method.
- REDIRECT_METHODS
Public Class Methods
# File lib/pg/connection.rb, line 281 def self.async_api=(enable) REDIRECT_METHODS.each do |ali, (async, sync)| remove_method(ali) if method_defined?(ali) alias_method( ali, enable ? async : sync ) end end
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
static VALUE pgconn_s_conndefaults(VALUE self) { PQconninfoOption *options = PQconndefaults(); VALUE array = pgconn_make_conninfo_array( options ); PQconninfoFree(options); UNUSED( self ); return array; }
Return the Postgres connection defaults structure as a Hash keyed by option keyword (as a Symbol).
See also conndefaults
# File lib/pg/connection.rb, line 227 def self.conndefaults_hash return self.conndefaults.each_with_object({}) do |info, hash| hash[ info[:keyword].to_sym ] = info[:val] end end
This is an asynchronous version of PG::Connection.new
.
Use connect_poll
to poll the status of the connection.
NOTE: this does not set the connection's client_encoding
for you if Encoding.default_internal
is set. To set it after the connection is established, call internal_encoding=
. You can also set it automatically by setting ENV['PGCLIENTENCODING']
, or include the 'options' connection parameter.
See also the 'sample' directory of this gem and the corresponding libpq functions.
static VALUE pgconn_s_connect_start( int argc, VALUE *argv, VALUE klass ) { VALUE rb_conn; VALUE conninfo; VALUE error; t_pg_connection *this; /* * PG::Connection.connect_start must act as both alloc() and initialize() * because it is not invoked by calling new(). */ rb_conn = pgconn_s_allocate( klass ); this = pg_get_connection( rb_conn ); conninfo = rb_funcall2( klass, rb_intern("parse_connect_args"), argc, argv ); this->pgconn = gvl_PQconnectStart( StringValueCStr(conninfo) ); if( this->pgconn == NULL ) rb_raise(rb_ePGerror, "PQconnectStart() unable to allocate structure"); if ( PQstatus(this->pgconn) == CONNECTION_BAD ) { error = rb_exc_new2(rb_eConnectionBad, PQerrorMessage(this->pgconn)); 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; }
This is an older, deprecated version of encrypt_password
. The difference is that this function always uses md5
as the encryption algorithm.
static VALUE pgconn_s_encrypt_password(VALUE self, VALUE password, VALUE username) { char *encrypted = NULL; VALUE rval = Qnil; UNUSED( self ); Check_Type(password, T_STRING); Check_Type(username, T_STRING); encrypted = PQencryptPassword(StringValueCStr(password), StringValueCStr(username)); rval = rb_str_new2( encrypted ); PQfreemem( encrypted ); return rval; }
Escapes binary data for use within an SQL command with the type bytea
.
Certain byte values must be escaped (but all byte values may be escaped) when used as part of a bytea
literal in an SQL statement. In general, to escape a byte, it is converted into the three digit octal number equal to the octet value, and preceded by two backslashes. The single quote (') and backslash () characters have special alternative escape sequences. escape_bytea
performs this operation, escaping only the minimally required bytes.
Consider using exec_params
, which avoids the need for passing values inside of SQL commands.
NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.
static VALUE pgconn_s_escape_bytea(VALUE self, VALUE str) { unsigned char *from, *to; size_t from_len, to_len; VALUE ret; Check_Type(str, T_STRING); from = (unsigned char*)RSTRING_PTR(str); from_len = RSTRING_LEN(str); if ( rb_obj_is_kind_of(self, rb_cPGconn) ) { to = PQescapeByteaConn(pg_get_pgconn(self), from, from_len, &to_len); } else { to = PQescapeBytea( from, from_len, &to_len); } ret = rb_str_new((char*)to, to_len - 1); PQfreemem(to); return ret; }
Returns a SQL-safe version of the String str. This is the preferred way to make strings safe for inclusion in SQL queries.
Consider using exec_params
, which avoids the need for passing values inside of SQL commands.
Character encoding of escaped string will be equal to client encoding of connection.
NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.
See also convenience functions escape_literal
and escape_identifier
which also add proper quotes around the string.
static VALUE pgconn_s_escape(VALUE self, VALUE string) { size_t size; int error; VALUE result; int enc_idx; int singleton = !rb_obj_is_kind_of(self, rb_cPGconn); StringValueCStr(string); enc_idx = singleton ? ENCODING_GET(string) : pg_get_connection(self)->enc_idx; if( ENCODING_GET(string) != enc_idx ){ string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx)); } result = rb_str_new(NULL, RSTRING_LEN(string) * 2 + 1); PG_ENCODING_SET_NOCHECK(result, enc_idx); if( !singleton ) { size = PQescapeStringConn(pg_get_pgconn(self), RSTRING_PTR(result), RSTRING_PTR(string), RSTRING_LEN(string), &error); if(error) { rb_raise(rb_ePGerror, "%s", PQerrorMessage(pg_get_pgconn(self))); } } else { size = PQescapeString(RSTRING_PTR(result), RSTRING_PTR(string), RSTRING_LEN(string)); } rb_str_set_len(result, size); return result; }
Create a connection to the specified server.
connection_hash
must be a ruby Hash with connection parameters. See the list of valid parameters in the PostgreSQL documentation.
There are two accepted formats for connection_string
: plain keyword = value
strings and URIs. See the documentation of connection strings.
The positional parameter form has the same functionality except that the missing parameters will always take on default values. The parameters are:
host
-
server hostname
port
-
server port number
options
-
backend options
tty
-
(ignored in newer versions of PostgreSQL)
dbname
-
connecting database name
user
-
login user name
password
-
login password
Examples:
# Connect using all defaults PG::Connection.new # As a Hash PG::Connection.new( :dbname => 'test', :port => 5432 ) # As a String PG::Connection.new( "dbname=test port=5432" ) # As an Array PG::Connection.new( nil, 5432, nil, nil, 'test', nil, nil )
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.
static VALUE pgconn_init(int argc, VALUE *argv, VALUE self) { t_pg_connection *this; VALUE conninfo; VALUE error; this = pg_get_connection( self ); conninfo = rb_funcall2( rb_cPGconn, rb_intern("parse_connect_args"), argc, argv ); this->pgconn = gvl_PQconnectdb(StringValueCStr(conninfo)); if(this->pgconn == NULL) rb_raise(rb_ePGerror, "PQconnectdb() unable to allocate structure"); if (PQstatus(this->pgconn) == CONNECTION_BAD) { error = rb_exc_new2(rb_eConnectionBad, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } pgconn_set_default_encoding( self ); if (rb_block_given_p()) { return rb_ensure(rb_yield, self, pgconn_finish, self); } return self; }
Parse the connection args
into a connection-parameter string. See PG::Connection.new
for valid arguments.
# File lib/pg/connection.rb, line 35 def self::parse_connect_args( *args ) return '' if args.empty? hash_arg = args.last.is_a?( Hash ) ? args.pop : {} option_string = '' options = {} # 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 } options[:fallback_application_name] = $0.sub( /^(.{30}).{4,}(.{30})$/ ){ $1+"..."+$2 } end if args.length == 1 case args.first when URI, /\A#{URI::ABS_URI_REF}\z/ uri = URI(args.first) options.merge!( Hash[URI.decode_www_form( uri.query )] ) if uri.query when /=/ # Option string style option_string = args.first.to_s else # Positional parameters options[CONNECT_ARGUMENT_ORDER.first.to_sym] = args.first end else max = CONNECT_ARGUMENT_ORDER.length raise ArgumentError, "Extra positional parameter %d: %p" % [ max + 1, args[max] ] if args.length > max CONNECT_ARGUMENT_ORDER.zip( args ) do |(k,v)| options[ k.to_sym ] = v if v end end options.merge!( hash_arg ) if uri uri.host = nil if options[:host] uri.port = nil if options[:port] uri.user = nil if options[:user] uri.password = nil if options[:password] uri.path = '' if options[:dbname] uri.query = URI.encode_www_form( options ) return uri.to_s.sub( /^#{uri.scheme}:(?!\/\/)/, "#{uri.scheme}://" ) else option_string += ' ' unless option_string.empty? && options.empty? return option_string + options.map { |k,v| "#{k}=#{quote_connstr(v)}" }.join( ' ' ) end end
Check server status.
See PG::Connection.new
for a description of the parameters.
Returns one of:
PQPING_OK
-
server is accepting connections
PQPING_REJECT
-
server is alive but rejecting connections
PQPING_NO_RESPONSE
-
could not establish connection
PQPING_NO_ATTEMPT
-
connection not attempted (bad params)
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( StringValueCStr(conninfo) ); return INT2FIX((int)ping); }
Quote the given value
for use in a connection-parameter string.
# File lib/pg/connection.rb, line 28 def self::quote_connstr( value ) return "'" + value.to_s.gsub( /[\\']/ ) {|m| '\\' + m } + "'" end
Returns a string that is safe for inclusion in a SQL query as an identifier. Note: this is not a quote function for values, but for identifiers.
For example, in a typical SQL query: SELECT FOO FROM MYTABLE
The identifier FOO
is folded to lower case, so it actually means foo
. If you really want to access the case-sensitive field name FOO
, use this function like conn.quote_ident('FOO')
, which will return "FOO"
(with double-quotes). PostgreSQL will see the double-quotes, and it will not fold to lower case.
Similarly, this function also protects against special characters, and other things that might allow SQL injection if the identifier comes from an untrusted source.
If the parameter is an Array, then all it's values are separately quoted and then joined by a “.” character. This can be used for identifiers in the form “schema”.“table”.“column” .
This method is functional identical to the encoder PG::TextEncoder::Identifier
.
If the instance method form is used and the input string character encoding is different to the connection encoding, then the string is converted to this encoding, so that the returned string is always encoded as PG::Connection#internal_encoding
.
In the singleton form (PG::Connection.quote_ident
) the character encoding of the result string is set to the character encoding of the input string.
static VALUE pgconn_s_quote_ident(VALUE self, VALUE str_or_array) { VALUE ret; int enc_idx; if( rb_obj_is_kind_of(self, rb_cPGconn) ){ enc_idx = pg_get_connection(self)->enc_idx; }else{ enc_idx = RB_TYPE_P(str_or_array, T_STRING) ? ENCODING_GET( str_or_array ) : rb_ascii8bit_encindex(); } pg_text_enc_identifier(NULL, str_or_array, NULL, &ret, enc_idx); return ret; }
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.
static VALUE pgconn_s_unescape_bytea(VALUE self, VALUE str) { unsigned char *from, *to; size_t to_len; VALUE ret; UNUSED( self ); Check_Type(str, T_STRING); from = (unsigned char*)StringValueCStr(str); to = PQunescapeBytea(from, &to_len); ret = rb_str_new((char*)to, to_len); PQfreemem(to); return ret; }
Public Instance Methods
Retrieve information about the portal portal_name.
See also corresponding libpq function.
Retrieve information about the prepared statement statement_name.
See also corresponding libpq function.
Sends SQL query request specified by sql to PostgreSQL. On success, it returns a PG::Result
instance with all result rows and columns. On failure, it raises a PG::Error
.
For backward compatibility, if you pass more than one parameter to this method, it will call exec_params
for you. New code should explicitly use exec_params
if argument placeholders are used.
If the optional code block is given, it will be passed result as an argument, and the PG::Result
object will automatically be cleared when the block terminates. In this instance, conn.exec
returns the value of the block.
exec
is an alias for async_exec
which is almost identical to sync_exec
. sync_exec
is implemented on the simpler synchronous command processing API of libpq, whereas async_exec
is implemented on the asynchronous API and on ruby's IO mechanisms. Both methods ensure that other threads can process while waiting for the server to complete the request, but sync_exec
blocks all signals to be processed until the query is finished. This is most notably visible by a delayed reaction to Control+C. It's not recommended to use explicit sync or async variants but exec
instead, unless you have a good reason to do so.
See also corresponding libpq function.
Sends SQL query request specified by sql
to PostgreSQL using placeholders for parameters.
Returns a PG::Result
instance on success. On failure, it raises a PG::Error
.
params
is an array of the bind parameters for the SQL query. Each element of the params
array may be either:
a hash of the form: {:value => String (value of bind parameter) :type => Integer (oid of type of bind parameter) :format => Integer (0 for text, 1 for binary) } or, it may be a String. If it is a string, that is equivalent to the hash: { :value => <string value>, :type => 0, :format => 0 }
PostgreSQL bind parameters are represented as $1, $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.
type_map
can be a PG::TypeMap
derivation (such as PG::BasicTypeMapForQueries
). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.
If the optional code block is given, it will be passed result as an argument, and the PG::Result
object will automatically be cleared when the block terminates. In this instance, conn.exec
returns the value of the block.
The primary advantage of exec_params
over exec
is that parameter values can be separated from the command string, thus avoiding the need for tedious and error-prone quoting and escaping. Unlike exec
, exec_params
allows at most one SQL command in the given string. (There can be semicolons in it, but not more than one nonempty command.) This is a limitation of the underlying protocol, but has some usefulness as an extra defense against SQL-injection attacks.
See also corresponding libpq function.
Execute prepared named statement specified by statement_name. Returns a PG::Result
instance on success. On failure, it raises a PG::Error
.
params
is an array of the optional bind parameters for the SQL query. Each element of the params
array may be either:
a hash of the form: {:value => String (value of bind parameter) :format => Integer (0 for text, 1 for binary) } or, it may be a String. If it is a string, that is equivalent to the hash: { :value => <string value>, :format => 0 }
PostgreSQL bind parameters are represented as $1, $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.
type_map
can be a PG::TypeMap
derivation (such as PG::BasicTypeMapForQueries
). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.
If the optional code block is given, it will be passed result as an argument, and the PG::Result
object will automatically be cleared when the block terminates. In this instance, conn.exec_prepared
returns the value of the block.
See also corresponding libpq function.
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.
See also corresponding libpq function.
Sends SQL query request specified by sql to PostgreSQL. On success, it returns a PG::Result
instance with all result rows and columns. On failure, it raises a PG::Error
.
For backward compatibility, if you pass more than one parameter to this method, it will call exec_params
for you. New code should explicitly use exec_params
if argument placeholders are used.
If the optional code block is given, it will be passed result as an argument, and the PG::Result
object will automatically be cleared when the block terminates. In this instance, conn.exec
returns the value of the block.
exec
is an alias for async_exec
which is almost identical to sync_exec
. sync_exec
is implemented on the simpler synchronous command processing API of libpq, whereas async_exec
is implemented on the asynchronous API and on ruby's IO mechanisms. Both methods ensure that other threads can process while waiting for the server to complete the request, but sync_exec
blocks all signals to be processed until the query is finished. This is most notably visible by a delayed reaction to Control+C. It's not recommended to use explicit sync or async variants but exec
instead, unless you have a good reason to do so.
See also corresponding libpq function.
Returns the process ID of the backend server process for this connection. Note that this is a PID on database server host.
static VALUE pgconn_backend_pid(VALUE self) { return INT2NUM(PQbackendPID(pg_get_pgconn(self))); }
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.
static VALUE pgconn_block( int argc, VALUE *argv, VALUE self ) { PGconn *conn = pg_get_pgconn( self ); struct timeval timeout; struct timeval *ptimeout = NULL; VALUE timeout_in; double timeout_sec; void *ret; if ( rb_scan_args(argc, argv, "01", &timeout_in) == 1 ) { timeout_sec = NUM2DBL( timeout_in ); timeout.tv_sec = (time_t)timeout_sec; timeout.tv_usec = (suseconds_t)((timeout_sec - (long)timeout_sec) * 1e6); ptimeout = &timeout; } ret = wait_socket_readable( conn, ptimeout, get_result_readable); if( !ret ) return Qfalse; return Qtrue; }
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.
static VALUE pgconn_cancel(VALUE self) { 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; }
Sets the client encoding to the encoding String.
Closes the backend connection.
Returns an array of Hashes with connection defaults. See ::conndefaults
for details.
# File lib/pg/connection.rb, line 219 def conndefaults return self.class.conndefaults end
Returns a Hash with connection defaults. See ::conndefaults_hash
for details.
# File lib/pg/connection.rb, line 235 def conndefaults_hash return self.class.conndefaults_hash end
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.
static VALUE pgconn_connect_poll(VALUE self) { PostgresPollingStatusType status; status = gvl_PQconnectPoll(pg_get_pgconn(self)); return INT2FIX((int)status); }
Returns true
if the authentication method required a password, but none was available. false
otherwise.
static VALUE pgconn_connection_needs_password(VALUE self) { return PQconnectionNeedsPassword(pg_get_pgconn(self)) ? Qtrue : Qfalse; }
Returns true
if the authentication method used a caller-supplied password, false
otherwise.
static VALUE pgconn_connection_used_password(VALUE self) { return PQconnectionUsedPassword(pg_get_pgconn(self)) ? Qtrue : Qfalse; }
Returns the connection options used by a live connection.
Available since PostgreSQL-9.3
static VALUE pgconn_conninfo( VALUE self ) { PGconn *conn = pg_get_pgconn(self); PQconninfoOption *options = PQconninfo( conn ); VALUE array = pgconn_make_conninfo_array( options ); PQconninfoFree(options); return array; }
Return the Postgres connection info structure as a Hash keyed by option keyword (as a Symbol).
See also conninfo
# File lib/pg/connection.rb, line 246 def conninfo_hash return self.conninfo.each_with_object({}) do |info, hash| hash[ info[:keyword].to_sym ] = info[:val] end end
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.
static VALUE pgconn_consume_input(self) VALUE self; { VALUE error; PGconn *conn = pg_get_pgconn(self); /* returns 0 on error */ if(PQconsumeInput(conn) == 0) { error = rb_exc_new2(rb_eConnectionBad, PQerrorMessage(conn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } return Qnil; }
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
.
coder can be a PG::Coder
derivation (typically PG::TextEncoder::CopyRow
or PG::TextDecoder::CopyRow
). This enables encoding of data fields given to put_copy_data
or decoding of fields received by get_copy_data
.
Example with CSV input format:
conn.exec "create table my_table (a text,b text,c text,d text)" conn.copy_data "COPY my_table FROM STDIN CSV" do conn.put_copy_data "some,data,to,copy\n" conn.put_copy_data "more,data,to,copy\n" end
This creates my_table
and inserts two CSV rows.
The same with text format encoder PG::TextEncoder::CopyRow
and Array input:
enco = PG::TextEncoder::CopyRow.new conn.copy_data "COPY my_table FROM STDIN", enco do conn.put_copy_data ['some', 'data', 'to', 'copy'] conn.put_copy_data ['more', 'data', 'to', 'copy'] end
Example with CSV output format:
conn.copy_data "COPY my_table TO STDOUT CSV" do while row=conn.get_copy_data p row end end
This prints all rows of my_table
to stdout:
"some,data,to,copy\n" "more,data,to,copy\n"
The same with text format decoder PG::TextDecoder::CopyRow
and Array output:
deco = PG::TextDecoder::CopyRow.new conn.copy_data "COPY my_table TO STDOUT", deco do while row=conn.get_copy_data p row end end
This receives all rows of my_table
as ruby array:
["some", "data", "to", "copy"] ["more", "data", "to", "copy"]
# File lib/pg/connection.rb, line 155 def copy_data( sql, coder=nil ) res = exec( sql ) case res.result_status when PGRES_COPY_IN begin if coder old_coder = self.encoder_for_put_copy_data self.encoder_for_put_copy_data = coder end yield res rescue Exception => err errmsg = "%s while copy data: %s" % [ err.class.name, err.message ] put_copy_end( errmsg ) get_result raise else put_copy_end get_last_result ensure self.encoder_for_put_copy_data = old_coder if coder end when PGRES_COPY_OUT begin if coder old_coder = self.decoder_for_get_copy_data self.decoder_for_get_copy_data = coder end yield res rescue Exception => err cancel while get_copy_data end while get_result end raise else res = get_last_result if !res || 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 ensure self.decoder_for_get_copy_data = old_coder if coder end else raise ArgumentError, "SQL command is no COPY statement: #{sql}" end end
Returns the connected database name.
static VALUE pgconn_db(VALUE self) { char *db = PQdb(pg_get_pgconn(self)); if (!db) return Qnil; return rb_str_new2(db); }
Returns the default coder object that is currently set for type casting of received data by get_copy_data
.
Returns either:
-
a kind of
PG::Coder
-
nil
- type encoding is disabled, returned data will be a String.
static VALUE pgconn_decoder_for_get_copy_data_get(VALUE self) { t_pg_connection *this = pg_get_connection( self ); return this->decoder_for_get_copy_data; }
Set the default coder that is used for type casting of received data by get_copy_data
.
decoder
can be:
-
a kind of
PG::Coder
-
nil
- disable type decoding, returned data will be a String.
static VALUE pgconn_decoder_for_get_copy_data_set(VALUE self, VALUE typemap) { t_pg_connection *this = pg_get_connection( self ); if( typemap != Qnil ){ if ( !rb_obj_is_kind_of(typemap, rb_cPG_Coder) ) { rb_raise( rb_eTypeError, "wrong argument type %s (expected kind of PG::Coder)", rb_obj_classname( typemap ) ); } Check_Type(typemap, T_DATA); } this->decoder_for_get_copy_data = typemap; return typemap; }
Retrieve information about the portal portal_name.
See also corresponding libpq function.
static VALUE pgconn_async_describe_portal(VALUE self, VALUE portal) { VALUE rb_pgresult = Qnil; pgconn_discard_results( self ); pgconn_send_describe_portal( self, portal ); pgconn_block( 0, NULL, self ); /* wait for input (without blocking) before reading the last result */ 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; }
Retrieve information about the prepared statement statement_name.
See also corresponding libpq function.
static VALUE pgconn_async_describe_prepared(VALUE self, VALUE stmt_name) { VALUE rb_pgresult = Qnil; pgconn_discard_results( self ); pgconn_send_describe_prepared( self, stmt_name ); pgconn_block( 0, NULL, self ); /* wait for input (without blocking) before reading the last result */ 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; }
Silently discard any prior query result that application didn't eat. This is done prior of Connection#exec
and sibling methods and can be called explicitly when using the async API.
static VALUE pgconn_discard_results(VALUE self) { PGconn *conn = pg_get_pgconn(self); PGresult *cur; while ((cur = gvl_PQgetResult(conn)) != NULL) { int status = PQresultStatus(cur); PQclear(cur); if (status == PGRES_COPY_IN){ gvl_PQputCopyEnd(conn, "COPY terminated by new PQexec"); } if (status == PGRES_COPY_OUT){ char *buffer = NULL; while( gvl_PQgetCopyData(conn, &buffer, 0) > 0) PQfreemem(buffer); } } return Qnil; }
Returns the default coder object that is currently set for type casting of parameters to put_copy_data
.
Returns either:
-
a kind of
PG::Coder
-
nil
- type encoding is disabled, data must be a String.
static VALUE pgconn_encoder_for_put_copy_data_get(VALUE self) { t_pg_connection *this = pg_get_connection( self ); return this->encoder_for_put_copy_data; }
Set the default coder that is used for type casting of parameters to put_copy_data
.
encoder
can be:
-
a kind of
PG::Coder
-
nil
- disable type encoding, data must be a String.
static VALUE pgconn_encoder_for_put_copy_data_set(VALUE self, VALUE typemap) { t_pg_connection *this = pg_get_connection( self ); if( typemap != Qnil ){ if ( !rb_obj_is_kind_of(typemap, rb_cPG_Coder) ) { rb_raise( rb_eTypeError, "wrong argument type %s (expected kind of PG::Coder)", rb_obj_classname( typemap ) ); } Check_Type(typemap, T_DATA); } this->encoder_for_put_copy_data = typemap; return typemap; }
This function is intended to be used by client applications that wish to send commands like ALTER USER joe PASSWORD 'pwd'
. It is good practice not to send the original cleartext password in such a command, because it might be exposed in command logs, activity displays, and so on. Instead, use this function to convert the password to encrypted form before it is sent.
The password
and username
arguments are the cleartext password, and the SQL name of the user it is for. algorithm
specifies the encryption algorithm to use to encrypt the password. Currently supported algorithms are md5
and scram-sha-256
(on
and off
are also accepted as aliases for md5
, for compatibility with older server versions). Note that support for scram-sha-256
was introduced in PostgreSQL version 10, and will not work correctly with older server versions. If algorithm is omitted or nil
, this function will query the server for the current value of the password_encryption
setting. That can block, and will fail if the current transaction is aborted, or if the connection is busy executing another query. If you wish to use the default algorithm for the server but want to avoid blocking, query password_encryption
yourself before calling encrypt_password
, and pass that value as the algorithm.
Return value is the encrypted password. The caller can assume the string doesn't contain any special characters that would require escaping.
Available since PostgreSQL-10. See also corresponding libpq function.
static VALUE pgconn_encrypt_password(int argc, VALUE *argv, VALUE self) { char *encrypted = NULL; VALUE rval = Qnil; VALUE password, username, algorithm; PGconn *conn = pg_get_pgconn(self); rb_scan_args( argc, argv, "21", &password, &username, &algorithm ); Check_Type(password, T_STRING); Check_Type(username, T_STRING); encrypted = gvl_PQencryptPasswordConn(conn, StringValueCStr(password), StringValueCStr(username), RTEST(algorithm) ? StringValueCStr(algorithm) : NULL); if ( encrypted ) { rval = rb_str_new2( encrypted ); PQfreemem( encrypted ); } else { rb_raise(rb_ePGerror, "%s", PQerrorMessage(conn)); } return rval; }
Returns the error message about connection.
static VALUE pgconn_error_message(VALUE self) { char *error = PQerrorMessage(pg_get_pgconn(self)); if (!error) return Qnil; return rb_str_new2(error); }
Returns a SQL-safe version of the String str. This is the preferred way to make strings safe for inclusion in SQL queries.
Consider using exec_params
, which avoids the need for passing values inside of SQL commands.
Character encoding of escaped string will be equal to client encoding of connection.
NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.
See also convenience functions escape_literal
and escape_identifier
which also add proper quotes around the string.
Escapes binary data for use within an SQL command with the type bytea
.
Certain byte values must be escaped (but all byte values may be escaped) when used as part of a bytea
literal in an SQL statement. In general, to escape a byte, it is converted into the three digit octal number equal to the octet value, and preceded by two backslashes. The single quote (') and backslash () characters have special alternative escape sequences. escape_bytea
performs this operation, escaping only the minimally required bytes.
Consider using exec_params
, which avoids the need for passing values inside of SQL commands.
NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.
static VALUE pgconn_s_escape_bytea(VALUE self, VALUE str) { unsigned char *from, *to; size_t from_len, to_len; VALUE ret; Check_Type(str, T_STRING); from = (unsigned char*)RSTRING_PTR(str); from_len = RSTRING_LEN(str); if ( rb_obj_is_kind_of(self, rb_cPGconn) ) { to = PQescapeByteaConn(pg_get_pgconn(self), from, from_len, &to_len); } else { to = PQescapeBytea( from, from_len, &to_len); } ret = rb_str_new((char*)to, to_len - 1); PQfreemem(to); return ret; }
Escape an arbitrary String str
as an identifier.
This method does the same as quote_ident
with a String argument, but it doesn't support an Array argument and it makes use of libpq to process the string.
static VALUE pgconn_escape_identifier(VALUE self, VALUE string) { t_pg_connection *this = pg_get_connection_safe( self ); char *escaped = NULL; VALUE error; VALUE result = Qnil; int enc_idx = this->enc_idx; StringValueCStr(string); if( ENCODING_GET(string) != enc_idx ){ string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx)); } escaped = PQescapeIdentifier(this->pgconn, RSTRING_PTR(string), RSTRING_LEN(string)); if (escaped == NULL) { error = rb_exc_new2(rb_ePGerror, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); return Qnil; } result = rb_str_new2(escaped); PQfreemem(escaped); PG_ENCODING_SET_NOCHECK(result, enc_idx); return result; }
Escape an arbitrary String str
as a literal.
See also PG::TextEncoder::QuotedLiteral
for a type cast integrated version of this function.
static VALUE pgconn_escape_literal(VALUE self, VALUE string) { t_pg_connection *this = pg_get_connection_safe( self ); char *escaped = NULL; VALUE error; VALUE result = Qnil; int enc_idx = this->enc_idx; StringValueCStr(string); if( ENCODING_GET(string) != enc_idx ){ string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx)); } escaped = PQescapeLiteral(this->pgconn, RSTRING_PTR(string), RSTRING_LEN(string)); if (escaped == NULL) { error = rb_exc_new2(rb_ePGerror, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); return Qnil; } result = rb_str_new2(escaped); PQfreemem(escaped); PG_ENCODING_SET_NOCHECK(result, enc_idx); return result; }
Returns a SQL-safe version of the String str. This is the preferred way to make strings safe for inclusion in SQL queries.
Consider using exec_params
, which avoids the need for passing values inside of SQL commands.
Character encoding of escaped string will be equal to client encoding of connection.
NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.
See also convenience functions escape_literal
and escape_identifier
which also add proper quotes around the string.
static VALUE pgconn_s_escape(VALUE self, VALUE string) { size_t size; int error; VALUE result; int enc_idx; int singleton = !rb_obj_is_kind_of(self, rb_cPGconn); StringValueCStr(string); enc_idx = singleton ? ENCODING_GET(string) : pg_get_connection(self)->enc_idx; if( ENCODING_GET(string) != enc_idx ){ string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx)); } result = rb_str_new(NULL, RSTRING_LEN(string) * 2 + 1); PG_ENCODING_SET_NOCHECK(result, enc_idx); if( !singleton ) { size = PQescapeStringConn(pg_get_pgconn(self), RSTRING_PTR(result), RSTRING_PTR(string), RSTRING_LEN(string), &error); if(error) { rb_raise(rb_ePGerror, "%s", PQerrorMessage(pg_get_pgconn(self))); } } else { size = PQescapeString(RSTRING_PTR(result), RSTRING_PTR(string), RSTRING_LEN(string)); } rb_str_set_len(result, size); return result; }
Sends SQL query request specified by sql to PostgreSQL. On success, it returns a PG::Result
instance with all result rows and columns. On failure, it raises a PG::Error
.
For backward compatibility, if you pass more than one parameter to this method, it will call exec_params
for you. New code should explicitly use exec_params
if argument placeholders are used.
If the optional code block is given, it will be passed result as an argument, and the PG::Result
object will automatically be cleared when the block terminates. In this instance, conn.exec
returns the value of the block.
exec
is an alias for async_exec
which is almost identical to sync_exec
. sync_exec
is implemented on the simpler synchronous command processing API of libpq, whereas async_exec
is implemented on the asynchronous API and on ruby's IO mechanisms. Both methods ensure that other threads can process while waiting for the server to complete the request, but sync_exec
blocks all signals to be processed until the query is finished. This is most notably visible by a delayed reaction to Control+C. It's not recommended to use explicit sync or async variants but exec
instead, unless you have a good reason to do so.
See also corresponding libpq function.
static VALUE pgconn_async_exec(int argc, VALUE *argv, VALUE self) { VALUE rb_pgresult = Qnil; pgconn_discard_results( self ); pgconn_send_query( argc, argv, self ); pgconn_block( 0, NULL, self ); /* wait for input (without blocking) before reading the last result */ 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; }
Sends SQL query request specified by sql
to PostgreSQL using placeholders for parameters.
Returns a PG::Result
instance on success. On failure, it raises a PG::Error
.
params
is an array of the bind parameters for the SQL query. Each element of the params
array may be either:
a hash of the form: {:value => String (value of bind parameter) :type => Integer (oid of type of bind parameter) :format => Integer (0 for text, 1 for binary) } or, it may be a String. If it is a string, that is equivalent to the hash: { :value => <string value>, :type => 0, :format => 0 }
PostgreSQL bind parameters are represented as $1, $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.
type_map
can be a PG::TypeMap
derivation (such as PG::BasicTypeMapForQueries
). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.
If the optional code block is given, it will be passed result as an argument, and the PG::Result
object will automatically be cleared when the block terminates. In this instance, conn.exec
returns the value of the block.
The primary advantage of exec_params
over exec
is that parameter values can be separated from the command string, thus avoiding the need for tedious and error-prone quoting and escaping. Unlike exec
, exec_params
allows at most one SQL command in the given string. (There can be semicolons in it, but not more than one nonempty command.) This is a limitation of the underlying protocol, but has some usefulness as an extra defense against SQL-injection attacks.
See also corresponding libpq function.
static VALUE pgconn_async_exec_params(int argc, VALUE *argv, VALUE self) { VALUE rb_pgresult = Qnil; pgconn_discard_results( self ); /* If called with no or nil parameters, use PQsendQuery for compatibility */ if ( argc == 1 || (argc >= 2 && argc <= 4 && NIL_P(argv[1]) )) { pg_deprecated(3, ("forwarding async_exec_params to async_exec is deprecated")); pgconn_send_query( argc, argv, self ); } else { pgconn_send_query_params( argc, argv, self ); } pgconn_block( 0, NULL, self ); /* wait for input (without blocking) before reading the last result */ 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; }
Execute prepared named statement specified by statement_name. Returns a PG::Result
instance on success. On failure, it raises a PG::Error
.
params
is an array of the optional bind parameters for the SQL query. Each element of the params
array may be either:
a hash of the form: {:value => String (value of bind parameter) :format => Integer (0 for text, 1 for binary) } or, it may be a String. If it is a string, that is equivalent to the hash: { :value => <string value>, :format => 0 }
PostgreSQL bind parameters are represented as $1, $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.
type_map
can be a PG::TypeMap
derivation (such as PG::BasicTypeMapForQueries
). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.
If the optional code block is given, it will be passed result as an argument, and the PG::Result
object will automatically be cleared when the block terminates. In this instance, conn.exec_prepared
returns the value of the block.
See also corresponding libpq function.
static VALUE pgconn_async_exec_prepared(int argc, VALUE *argv, VALUE self) { VALUE rb_pgresult = Qnil; pgconn_discard_results( self ); pgconn_send_query_prepared( argc, argv, self ); pgconn_block( 0, NULL, self ); /* wait for input (without blocking) before reading the last result */ 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; }
Return the server_encoding
of the connected database as a Ruby Encoding object. The SQL_ASCII
encoding is mapped to to ASCII_8BIT
.
static VALUE pgconn_external_encoding(VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); rb_encoding *enc = NULL; const char *pg_encname = NULL; pg_encname = PQparameterStatus( this->pgconn, "server_encoding" ); enc = pg_get_pg_encname_as_rb_encoding( pg_encname ); return rb_enc_from_encoding( enc ); }
Get type of field names.
See description at field_name_type=
static VALUE pgconn_field_name_type_get(VALUE self) { t_pg_connection *this = pg_get_connection( self ); if( this->flags & PG_RESULT_FIELD_NAMES_SYMBOL ){ return sym_symbol; } else if( this->flags & PG_RESULT_FIELD_NAMES_STATIC_SYMBOL ){ return sym_static_symbol; } else { return sym_string; } }
Set default type of field names of results retrieved by this connection. It can be set to one of:
-
:string
to use String based field names -
:symbol
to use Symbol based field names
The default is :string
.
Settings the type of field names affects only future results.
See further description at PG::Result#field_name_type=
static VALUE pgconn_field_name_type_set(VALUE self, VALUE sym) { t_pg_connection *this = pg_get_connection( self ); this->flags &= ~PG_RESULT_FIELD_NAMES_MASK; if( sym == sym_symbol ) this->flags |= PG_RESULT_FIELD_NAMES_SYMBOL; else if ( sym == sym_static_symbol ) this->flags |= PG_RESULT_FIELD_NAMES_STATIC_SYMBOL; else if ( sym == sym_string ); else rb_raise(rb_eArgError, "invalid argument %+"PRIsVALUE, sym); return sym; }
Closes the backend connection.
static VALUE pgconn_finish( VALUE self ) { t_pg_connection *this = pg_get_connection_safe( self ); pgconn_close_socket_io( self ); PQfinish( this->pgconn ); this->pgconn = NULL; return Qnil; }
Returns true
if the backend connection has been closed.
static VALUE pgconn_finished_p( VALUE self ) { t_pg_connection *this = pg_get_connection( self ); if ( this->pgconn ) return Qfalse; return Qtrue; }
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.
static VALUE pgconn_flush(self) VALUE self; { PGconn *conn = pg_get_pgconn(self); int ret; VALUE error; ret = PQflush(conn); if(ret == -1) { error = rb_exc_new2(rb_ePGerror, PQerrorMessage(conn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } return (ret) ? Qfalse : Qtrue; }
Returns the client encoding as a String.
static VALUE pgconn_get_client_encoding(VALUE self) { char *encoding = (char *)pg_encoding_to_char(PQclientEncoding(pg_get_pgconn(self))); return rb_str_new2(encoding); }
Return one row of data, nil
if the copy is done, or false
if the call would block (only possible if async is true).
If decoder is not set or nil
, data is returned as binary string.
If decoder is set to a PG::Coder
derivation, the return type depends on this decoder. PG::TextDecoder::CopyRow
decodes the received data fields from one row of PostgreSQL's COPY text format to an Array of Strings. Optionally the decoder can type cast the single fields to various Ruby types in one step, if PG::TextDecoder::CopyRow#type_map
is set accordingly.
See also copy_data
.
static VALUE pgconn_get_copy_data(int argc, VALUE *argv, VALUE self ) { VALUE async_in; VALUE error; VALUE result; int ret; char *buffer; VALUE decoder; t_pg_coder *p_coder = NULL; t_pg_connection *this = pg_get_connection_safe( self ); rb_scan_args(argc, argv, "02", &async_in, &decoder); if( NIL_P(decoder) ){ if( !NIL_P(this->decoder_for_get_copy_data) ){ p_coder = DATA_PTR( this->decoder_for_get_copy_data ); } } else if( rb_obj_is_kind_of(decoder, rb_cPG_Coder) ) { Data_Get_Struct( decoder, t_pg_coder, p_coder ); } else { rb_raise( rb_eTypeError, "wrong decoder type %s (expected some kind of PG::Coder)", rb_obj_classname( decoder ) ); } ret = gvl_PQgetCopyData(this->pgconn, &buffer, RTEST(async_in)); if(ret == -2) { /* error */ error = rb_exc_new2(rb_ePGerror, PQerrorMessage(this->pgconn)); 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; } if( p_coder ){ t_pg_coder_dec_func dec_func = pg_coder_dec_func( p_coder, p_coder->format ); result = dec_func( p_coder, buffer, ret, 0, 0, this->enc_idx ); } else { result = rb_str_new(buffer, ret); } PQfreemem(buffer); return result; }
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.
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; }
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.
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; }
Returns the connected server name.
static VALUE pgconn_host(VALUE self) { char *host = PQhost(pg_get_pgconn(self)); if (!host) return Qnil; return rb_str_new2(host); }
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'
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; } }
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.
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", StringValueCStr(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 ( gvl_PQsetClientEncoding(pg_get_pgconn( self ), name) == -1 ) { VALUE server_encoding = pgconn_external_encoding( self ); rb_raise( rb_eEncCompatError, "incompatible character encodings: %s and %s", rb_enc_name(rb_to_encoding(server_encoding)), name ); } pgconn_set_internal_encoding_index( self ); return enc; } }
Returns true
if a command is busy, that is, if PQgetResult would block. Otherwise returns false
.
static VALUE pgconn_is_busy(self) VALUE self; { return gvl_PQisBusy(pg_get_pgconn(self)) ? Qtrue : Qfalse; }
Returns true
if a command is busy, that is, if PQgetResult would block. Otherwise returns false
.
static VALUE pgconn_isnonblocking(self) VALUE self; { return PQisnonblocking(pg_get_pgconn(self)) ? Qtrue : Qfalse; }
Closes the postgres large object of lo_desc.
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; }
Creates a large object with mode mode. Returns a large object Oid. On failure, it raises PG::Error
.
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 UINT2NUM(lo_oid); }
Creates a large object with oid oid. Returns the large object Oid. On failure, it raises PG::Error
.
static VALUE pgconn_locreate(VALUE self, VALUE in_lo_oid) { Oid ret, lo_oid; PGconn *conn = pg_get_pgconn(self); lo_oid = NUM2UINT(in_lo_oid); ret = lo_create(conn, lo_oid); if (ret == InvalidOid) rb_raise(rb_ePGerror, "lo_create failed"); return UINT2NUM(ret); }
Saves a large object of oid to a file.
static VALUE pgconn_loexport(VALUE self, VALUE lo_oid, VALUE filename) { PGconn *conn = pg_get_pgconn(self); Oid oid; Check_Type(filename, T_STRING); oid = NUM2UINT(lo_oid); if (lo_export(conn, oid, StringValueCStr(filename)) < 0) { rb_raise(rb_ePGerror, "%s", PQerrorMessage(conn)); } return Qnil; }
Import a file to a large object. Returns a large object Oid.
On failure, it raises a PG::Error
.
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, StringValueCStr(filename)); if (lo_oid == 0) { rb_raise(rb_ePGerror, "%s", PQerrorMessage(conn)); } return UINT2NUM(lo_oid); }
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.)
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); }
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
.
static VALUE pgconn_loopen(int argc, VALUE *argv, VALUE self) { Oid lo_oid; int fd, mode; VALUE nmode, selfid; PGconn *conn = pg_get_pgconn(self); rb_scan_args(argc, argv, "11", &selfid, &nmode); lo_oid = NUM2UINT(selfid); if(NIL_P(nmode)) mode = INV_READ; else mode = NUM2INT(nmode); if((fd = lo_open(conn, lo_oid, mode)) < 0) { rb_raise(rb_ePGerror, "can't open large object: %s", PQerrorMessage(conn)); } return INT2FIX(fd); }
Attempts to read len bytes from large object lo_desc, returns resulting data.
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_str_new(buffer, ret); xfree(buffer); return str; }
Move the large object pointer lo_desc to offset offset. Valid values for whence are SEEK_SET
, SEEK_CUR
, and SEEK_END
. (Or 0, 1, or 2.)
Returns the current position of the large object lo_desc.
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); }
Truncates the large object lo_desc to size len.
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.
static VALUE pgconn_lounlink(VALUE self, VALUE in_oid) { PGconn *conn = pg_get_pgconn(self); Oid oid = NUM2UINT(in_oid); if(lo_unlink(conn,oid) < 0) rb_raise(rb_ePGerror,"lo_unlink failed"); return Qnil; }
Writes the string buffer to the large object lo_desc. Returns the number of bytes written.
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); }
Closes the postgres large object of lo_desc.
Creates a large object with mode mode. Returns a large object Oid. On failure, it raises PG::Error
.
Creates a large object with oid oid. Returns the large object Oid. On failure, it raises PG::Error
.
Saves a large object of oid to a file.
Import a file to a large object. Returns a large object Oid.
On failure, it raises a PG::Error
.
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.)
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
.
Attempts to read len bytes from large object lo_desc, returns resulting data.
Move the large object pointer lo_desc to offset offset. Valid values for whence are SEEK_SET
, SEEK_CUR
, and SEEK_END
. (Or 0, 1, or 2.)
Returns the current position of the large object lo_desc.
Truncates the large object lo_desc to size len.
Unlinks (deletes) the postgres large object of oid.
Writes the string buffer to the large object lo_desc. Returns the number of bytes written.
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
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; }
Returns true
if a command is busy, that is, if PQgetResult would block. Otherwise returns false
.
Returns a hash of the unprocessed notifications. If there is no unprocessed notifier, it returns nil
.
static VALUE pgconn_notifies(VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); PGnotify *notification; VALUE hash; VALUE sym_relname, sym_be_pid, sym_extra; VALUE relname, be_pid, extra; sym_relname = ID2SYM(rb_intern("relname")); sym_be_pid = ID2SYM(rb_intern("be_pid")); sym_extra = ID2SYM(rb_intern("extra")); notification = gvl_PQnotifies(this->pgconn); if (notification == NULL) { return Qnil; } hash = rb_hash_new(); relname = rb_str_new2(notification->relname); be_pid = INT2NUM(notification->be_pid); extra = rb_str_new2(notification->extra); PG_ENCODING_SET_NOCHECK( relname, this->enc_idx ); PG_ENCODING_SET_NOCHECK( extra, this->enc_idx ); rb_hash_aset(hash, sym_relname, relname); rb_hash_aset(hash, sym_be_pid, be_pid); rb_hash_aset(hash, sym_extra, extra); PQfreemem(notification); return hash; }
Blocks while waiting for notification(s), or until the optional timeout is reached, whichever comes first. timeout is measured in seconds and can be fractional.
Returns nil
if timeout is reached, the name of the NOTIFY event otherwise. If used in block form, passes the name of the NOTIFY event
, the generating pid
and the optional payload
string into the block.
Returns backend option string.
static VALUE pgconn_options(VALUE self) { char *options = PQoptions(pg_get_pgconn(self)); if (!options) return Qnil; return rb_str_new2(options); }
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.
static VALUE pgconn_parameter_status(VALUE self, VALUE param_name) { const char *ret = PQparameterStatus(pg_get_pgconn(self), StringValueCStr(param_name)); if(ret == NULL) return Qnil; else return rb_str_new2(ret); }
Returns the authenticated password.
static VALUE pgconn_pass(VALUE self) { char *user = PQpass(pg_get_pgconn(self)); if (!user) return Qnil; return rb_str_new2(user); }
Returns the connected server port number.
static VALUE pgconn_port(VALUE self) { char* port = PQport(pg_get_pgconn(self)); return INT2NUM(atol(port)); }
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.
See also corresponding libpq function.
static VALUE pgconn_async_prepare(int argc, VALUE *argv, VALUE self) { VALUE rb_pgresult = Qnil; pgconn_discard_results( self ); pgconn_send_prepare( argc, argv, self ); pgconn_block( 0, NULL, self ); /* wait for input (without blocking) before reading the last result */ 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; }
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.)
static VALUE pgconn_protocol_version(VALUE self) { return INT2NUM(PQprotocolVersion(pg_get_pgconn(self))); }
Transmits buffer as copy data to the server. Returns true if the data was sent, false if it was not sent (false is only possible if the connection is in nonblocking mode, and this command would block).
encoder can be a PG::Coder
derivation (typically PG::TextEncoder::CopyRow
). This encodes the data fields given as buffer from an Array of Strings to PostgreSQL's COPY text format inclusive proper escaping. Optionally the encoder can type cast the fields from various Ruby types in one step, if PG::TextEncoder::CopyRow#type_map
is set accordingly.
Raises an exception if an error occurs.
See also copy_data
.
static VALUE pgconn_put_copy_data(int argc, VALUE *argv, VALUE self) { int ret; int len; t_pg_connection *this = pg_get_connection_safe( self ); VALUE value; VALUE buffer = Qnil; VALUE encoder; VALUE intermediate; t_pg_coder *p_coder = NULL; rb_scan_args( argc, argv, "11", &value, &encoder ); if( NIL_P(encoder) ){ if( NIL_P(this->encoder_for_put_copy_data) ){ buffer = value; } else { p_coder = DATA_PTR( this->encoder_for_put_copy_data ); } } else if( rb_obj_is_kind_of(encoder, rb_cPG_Coder) ) { Data_Get_Struct( encoder, t_pg_coder, p_coder ); } else { rb_raise( rb_eTypeError, "wrong encoder type %s (expected some kind of PG::Coder)", rb_obj_classname( encoder ) ); } if( p_coder ){ t_pg_coder_enc_func enc_func; int enc_idx = this->enc_idx; enc_func = pg_coder_enc_func( p_coder ); len = enc_func( p_coder, value, NULL, &intermediate, enc_idx); if( len == -1 ){ /* The intermediate value is a String that can be used directly. */ buffer = intermediate; } else { buffer = rb_str_new(NULL, len); len = enc_func( p_coder, value, RSTRING_PTR(buffer), &intermediate, enc_idx); rb_str_set_len( buffer, len ); } } Check_Type(buffer, T_STRING); ret = gvl_PQputCopyData(this->pgconn, RSTRING_PTR(buffer), RSTRING_LENINT(buffer)); if(ret == -1) { VALUE error = rb_exc_new2(rb_ePGerror, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } RB_GC_GUARD(intermediate); RB_GC_GUARD(buffer); return (ret) ? Qtrue : Qfalse; }
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).
static VALUE pgconn_put_copy_end(int argc, VALUE *argv, VALUE self) { VALUE str; VALUE error; int ret; const char *error_message = NULL; t_pg_connection *this = pg_get_connection_safe( self ); if (rb_scan_args(argc, argv, "01", &str) == 0) error_message = NULL; else error_message = pg_cstr_enc(str, this->enc_idx); ret = gvl_PQputCopyEnd(this->pgconn, error_message); if(ret == -1) { error = rb_exc_new2(rb_ePGerror, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } return (ret) ? Qtrue : Qfalse; }
Returns a string that is safe for inclusion in a SQL query as an identifier. Note: this is not a quote function for values, but for identifiers.
For example, in a typical SQL query: SELECT FOO FROM MYTABLE
The identifier FOO
is folded to lower case, so it actually means foo
. If you really want to access the case-sensitive field name FOO
, use this function like conn.quote_ident('FOO')
, which will return "FOO"
(with double-quotes). PostgreSQL will see the double-quotes, and it will not fold to lower case.
Similarly, this function also protects against special characters, and other things that might allow SQL injection if the identifier comes from an untrusted source.
If the parameter is an Array, then all it's values are separately quoted and then joined by a “.” character. This can be used for identifiers in the form “schema”.“table”.“column” .
This method is functional identical to the encoder PG::TextEncoder::Identifier
.
If the instance method form is used and the input string character encoding is different to the connection encoding, then the string is converted to this encoding, so that the returned string is always encoded as PG::Connection#internal_encoding
.
In the singleton form (PG::Connection.quote_ident
) the character encoding of the result string is set to the character encoding of the input string.
static VALUE pgconn_s_quote_ident(VALUE self, VALUE str_or_array) { VALUE ret; int enc_idx; if( rb_obj_is_kind_of(self, rb_cPGconn) ){ enc_idx = pg_get_connection(self)->enc_idx; }else{ enc_idx = RB_TYPE_P(str_or_array, T_STRING) ? ENCODING_GET( str_or_array ) : rb_ascii8bit_encindex(); } pg_text_enc_identifier(NULL, str_or_array, NULL, &ret, enc_idx); return ret; }
Resets the backend connection. This method closes the backend connection and tries to re-connect.
static VALUE pgconn_reset( VALUE self ) { pgconn_close_socket_io( self ); gvl_PQreset( pg_get_pgconn(self) ); return self; }
Checks the status of a connection reset operation. See connect_start and connect_poll
for usage information and return values.
static VALUE pgconn_reset_poll(VALUE self) { PostgresPollingStatusType status; status = gvl_PQresetPoll(pg_get_pgconn(self)); return INT2FIX((int)status); }
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.
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; }
Asynchronously send command to the server. Does not block. Use in combination with conn.get_result
.
static VALUE pgconn_send_describe_portal(VALUE self, VALUE portal) { VALUE error; t_pg_connection *this = pg_get_connection_safe( self ); /* returns 0 on failure */ if(gvl_PQsendDescribePortal(this->pgconn, pg_cstr_enc(portal, this->enc_idx)) == 0) { error = rb_exc_new2(rb_eUnableToSend, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } return Qnil; }
Asynchronously send command to the server. Does not block. Use in combination with conn.get_result
.
static VALUE pgconn_send_describe_prepared(VALUE self, VALUE stmt_name) { VALUE error; t_pg_connection *this = pg_get_connection_safe( self ); /* returns 0 on failure */ if(gvl_PQsendDescribePrepared(this->pgconn, pg_cstr_enc(stmt_name, this->enc_idx)) == 0) { error = rb_exc_new2(rb_eUnableToSend, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } return Qnil; }
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.
static VALUE pgconn_send_prepare(int argc, VALUE *argv, VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); int result; VALUE name, command, in_paramtypes; VALUE param; VALUE error; int i = 0; int nParams = 0; Oid *paramTypes = NULL; const char *name_cstr; const char *command_cstr; int enc_idx = this->enc_idx; rb_scan_args(argc, argv, "21", &name, &command, &in_paramtypes); name_cstr = pg_cstr_enc(name, enc_idx); command_cstr = pg_cstr_enc(command, enc_idx); if(! NIL_P(in_paramtypes)) { Check_Type(in_paramtypes, T_ARRAY); nParams = (int)RARRAY_LEN(in_paramtypes); paramTypes = ALLOC_N(Oid, nParams); for(i = 0; i < nParams; i++) { param = rb_ary_entry(in_paramtypes, i); if(param == Qnil) paramTypes[i] = 0; else paramTypes[i] = NUM2UINT(param); } } result = gvl_PQsendPrepare(this->pgconn, name_cstr, command_cstr, nParams, paramTypes); xfree(paramTypes); if(result == 0) { error = rb_exc_new2(rb_eUnableToSend, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } return Qnil; }
Sends SQL query request specified by sql to PostgreSQL for asynchronous processing, and immediately returns. On failure, it raises a PG::Error
.
For backward compatibility, if you pass more than one parameter to this method, it will call send_query_params
for you. New code should explicitly use send_query_params
if argument placeholders are used.
static VALUE pgconn_send_query(int argc, VALUE *argv, VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); VALUE error; /* If called with no or nil parameters, use PQexec for compatibility */ if ( argc == 1 || (argc >= 2 && argc <= 4 && NIL_P(argv[1]) )) { if(gvl_PQsendQuery(this->pgconn, pg_cstr_enc(argv[0], this->enc_idx)) == 0) { error = rb_exc_new2(rb_eUnableToSend, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } return Qnil; } pg_deprecated(2, ("forwarding async_exec to async_exec_params and send_query to send_query_params is deprecated")); /* If called with parameters, and optionally result_format, * use PQsendQueryParams */ return pgconn_send_query_params( argc, argv, self); }
Sends SQL query request specified by sql to PostgreSQL for asynchronous processing, and immediately returns. On failure, it raises a PG::Error
.
params
is an array of the bind parameters for the SQL query. Each element of the params
array may be either:
a hash of the form: {:value => String (value of bind parameter) :type => Integer (oid of type of bind parameter) :format => Integer (0 for text, 1 for binary) } or, it may be a String. If it is a string, that is equivalent to the hash: { :value => <string value>, :type => 0, :format => 0 }
PostgreSQL bind parameters are represented as $1, $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.
type_map
can be a PG::TypeMap
derivation (such as PG::BasicTypeMapForQueries
). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.
static VALUE pgconn_send_query_params(int argc, VALUE *argv, VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); int result; VALUE command, in_res_fmt; VALUE error; int nParams; int resultFormat; struct query_params_data paramsData = { this->enc_idx }; rb_scan_args(argc, argv, "22", &command, ¶msData.params, &in_res_fmt, ¶msData.typemap); paramsData.with_types = 1; pgconn_query_assign_typemap( self, ¶msData ); resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt); nParams = alloc_query_params( ¶msData ); result = gvl_PQsendQueryParams(this->pgconn, pg_cstr_enc(command, paramsData.enc_idx), nParams, paramsData.types, (const char * const *)paramsData.values, paramsData.lengths, paramsData.formats, resultFormat); free_query_params( ¶msData ); if(result == 0) { error = rb_exc_new2(rb_eUnableToSend, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } return Qnil; }
Execute prepared named statement specified by statement_name asynchronously, and returns immediately. On failure, it raises a PG::Error
.
params
is an array of the optional bind parameters for the SQL query. Each element of the params
array may be either:
a hash of the form: {:value => String (value of bind parameter) :format => Integer (0 for text, 1 for binary) } or, it may be a String. If it is a string, that is equivalent to the hash: { :value => <string value>, :format => 0 }
PostgreSQL bind parameters are represented as $1, $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.
type_map
can be a PG::TypeMap
derivation (such as PG::BasicTypeMapForQueries
). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.
static VALUE pgconn_send_query_prepared(int argc, VALUE *argv, VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); int result; VALUE name, in_res_fmt; VALUE error; int nParams; int resultFormat; struct query_params_data paramsData = { this->enc_idx }; rb_scan_args(argc, argv, "13", &name, ¶msData.params, &in_res_fmt, ¶msData.typemap); paramsData.with_types = 0; if(NIL_P(paramsData.params)) { paramsData.params = rb_ary_new2(0); resultFormat = 0; } pgconn_query_assign_typemap( self, ¶msData ); resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt); nParams = alloc_query_params( ¶msData ); result = gvl_PQsendQueryPrepared(this->pgconn, pg_cstr_enc(name, paramsData.enc_idx), nParams, (const char * const *)paramsData.values, paramsData.lengths, paramsData.formats, resultFormat); free_query_params( ¶msData ); if(result == 0) { error = rb_exc_new2(rb_eUnableToSend, PQerrorMessage(this->pgconn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } return Qnil; }
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.
static VALUE pgconn_server_version(VALUE self) { return INT2NUM(PQserverVersion(pg_get_pgconn(self))); }
Sets the client encoding to the encoding String.
static VALUE pgconn_set_client_encoding(VALUE self, VALUE str) { PGconn *conn = pg_get_pgconn( self ); Check_Type(str, T_STRING); if ( (gvl_PQsetClientEncoding(conn, StringValueCStr(str))) == -1 ) { rb_raise(rb_ePGerror, "%s", PQerrorMessage(conn)); } pgconn_set_internal_encoding_index( self ); return Qnil; }
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.
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 ( pgconn_set_client_encoding_async(self, encname) != 0 ) rb_warning( "Failed to set the default_internal encoding to %s: '%s'", encname, PQerrorMessage(conn) ); pgconn_set_internal_encoding_index( self ); return rb_enc_from_encoding( enc ); } else { pgconn_set_internal_encoding_index( self ); return Qnil; } }
Sets connection's context display mode to context_visibility and returns the previous setting. Available settings are:
-
PQSHOW_CONTEXT_NEVER
-
PQSHOW_CONTEXT_ERRORS
-
PQSHOW_CONTEXT_ALWAYS
This mode controls whether the CONTEXT field is included in messages (unless the verbosity setting is TERSE, in which case CONTEXT is never shown). The NEVER mode never includes CONTEXT, while ALWAYS always includes it if available. In ERRORS mode (the default), CONTEXT fields are included only for error messages, not for notices and warnings.
Changing this mode does not affect the messages available from already-existing PG::Result
objects, only subsequently-created ones. (But see PG::Result#verbose_error_message
if you want to print a previous error with a different display mode.)
See also corresponding libpq function.
Available since PostgreSQL-9.6
static VALUE pgconn_set_error_context_visibility(VALUE self, VALUE in_context_visibility) { PGconn *conn = pg_get_pgconn(self); PGContextVisibility context_visibility = NUM2INT(in_context_visibility); return INT2FIX(PQsetErrorContextVisibility(conn, context_visibility)); }
Sets connection's verbosity to verbosity and returns the previous setting. Available settings are:
-
PQERRORS_TERSE
-
PQERRORS_DEFAULT
-
PQERRORS_VERBOSE
-
PQERRORS_SQLSTATE
Changing the verbosity does not affect the messages available from already-existing PG::Result
objects, only subsequently-created ones. (But see PG::Result#verbose_error_message
if you want to print a previous error with a different verbosity.)
See also corresponding libpq function.
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)); }
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.
static VALUE pgconn_set_notice_processor(VALUE self) { VALUE proc, old_proc; t_pg_connection *this = pg_get_connection_safe( 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(this->pgconn, NULL, NULL); old_proc = this->notice_receiver; if( rb_block_given_p() ) { proc = rb_block_proc(); PQsetNoticeProcessor(this->pgconn, gvl_notice_processor_proxy, (void *)self); } else { /* if no block is given, set back to default */ proc = Qnil; PQsetNoticeProcessor(this->pgconn, default_notice_processor, NULL); } this->notice_receiver = proc; return old_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.
static VALUE pgconn_set_notice_receiver(VALUE self) { VALUE proc, old_proc; t_pg_connection *this = pg_get_connection_safe( 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(this->pgconn, NULL, NULL); old_proc = this->notice_receiver; if( rb_block_given_p() ) { proc = rb_block_proc(); PQsetNoticeReceiver(this->pgconn, gvl_notice_receiver_proxy, (void *)self); } else { /* if no block is given, set back to default */ proc = Qnil; PQsetNoticeReceiver(this->pgconn, default_notice_receiver, NULL); } this->notice_receiver = proc; return old_proc; }
To enter single-row mode, call this method immediately after a successful call of send_query
(or a sibling function). This mode selection is effective only for the currently executing query. Then call Connection#get_result
repeatedly, until it returns nil.
Each (but the last) received Result has exactly one row and a Result#result_status of PGRES_SINGLE_TUPLE. The last Result has zero rows and is used to indicate a successful execution of the query. All of these Result objects will contain the same row description data (column names, types, etc) that an ordinary Result object for the query would have.
Caution: While processing a query, the server may return some rows and then encounter an error, causing the query to be aborted. Ordinarily, pg discards any such rows and reports only the error. But in single-row mode, those rows will have already been returned to the application. Hence, the application will see some Result objects followed by an Error raised in get_result. For proper transactional behavior, the application must be designed to discard or undo whatever has been done with the previously-processed rows, if the query ultimately fails.
Example:
conn.send_query( "your SQL command" ) conn.set_single_row_mode loop do res = conn.get_result or break res.check res.each do |row| # do something with the received row end end
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; }
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
.
static VALUE pgconn_setnonblocking(self, state) VALUE self, state; { int arg; VALUE error; PGconn *conn = pg_get_pgconn(self); if(state == Qtrue) arg = 1; else if (state == Qfalse) arg = 0; else rb_raise(rb_eArgError, "Boolean value expected"); if(PQsetnonblocking(conn, arg) == -1) { error = rb_exc_new2(rb_ePGerror, PQerrorMessage(conn)); rb_iv_set(error, "@connection", self); rb_exc_raise(error); } return Qnil; }
This method is deprecated. Please use the more portable method socket_io
.
Returns the socket's file descriptor for this connection. IO.for_fd()
can be used to build a proper IO object to the socket. If you do so, you will likely also want to set autoclose=false
on it to prevent Ruby from closing the socket to PostgreSQL if it goes out of scope. Alternatively, you can use socket_io
, which creates an IO that's associated with the connection object itself, and so won't go out of scope until the connection does.
Note: On Windows the file descriptor is not usable, since it can not be used to build a Ruby IO object.
static VALUE pgconn_socket(VALUE self) { int sd; pg_deprecated(4, ("conn.socket is deprecated and should be replaced by conn.socket_io")); if( (sd = PQsocket(pg_get_pgconn(self))) < 0) rb_raise(rb_eConnectionBad, "PQsocket() can't get socket descriptor"); return INT2NUM(sd); }
Fetch a memorized 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. In contrast to socket
, it also works on Windows.
static VALUE pgconn_socket_io(VALUE self) { int sd; int ruby_sd; ID id_autoclose = rb_intern("autoclose="); t_pg_connection *this = pg_get_connection_safe( self ); VALUE socket_io = this->socket_io; if ( !RTEST(socket_io) ) { if( (sd = PQsocket(this->pgconn)) < 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); this->ruby_sd = ruby_sd; #else ruby_sd = sd; #endif socket_io = rb_funcall( rb_cIO, rb_intern("for_fd"), 1, INT2NUM(ruby_sd) ); /* Disable autoclose feature */ rb_funcall( socket_io, id_autoclose, 1, Qfalse ); this->socket_io = socket_io; } return socket_io; }
Returns SSL-related information about the connection.
The list of available attributes varies depending on the SSL library being used, and the type of connection. If an attribute is not available, returns nil.
The following attributes are commonly available:
library
-
Name of the SSL implementation in use. (Currently, only “OpenSSL” is implemented)
protocol
-
SSL/TLS version in use. Common values are “SSLv2”, “SSLv3”, “TLSv1”, “TLSv1.1” and “TLSv1.2”, but an implementation may return other strings if some other protocol is used.
key_bits
-
Number of key bits used by the encryption algorithm.
cipher
-
A short name of the ciphersuite used, e.g. “DHE-RSA-DES-CBC3-SHA”. The names are specific to each SSL implementation.
compression
-
If SSL compression is in use, returns the name of the compression algorithm, or “on” if compression is used but the algorithm is not known. If compression is not in use, returns “off”.
See also ssl_attribute_names
and the corresponding libpq function.
Available since PostgreSQL-9.5
static VALUE pgconn_ssl_attribute(VALUE self, VALUE attribute_name) { const char *p_attr; p_attr = PQsslAttribute(pg_get_pgconn(self), StringValueCStr(attribute_name)); return p_attr ? rb_str_new_cstr(p_attr) : Qnil; }
Return an array of SSL attribute names available.
See also ssl_attribute
Available since PostgreSQL-9.5
static VALUE pgconn_ssl_attribute_names(VALUE self) { int i; const char * const * p_list = PQsslAttributeNames(pg_get_pgconn(self)); VALUE ary = rb_ary_new(); for ( i = 0; p_list[i]; i++ ) { rb_ary_push( ary, rb_str_new_cstr( p_list[i] )); } return ary; }
Returns SSL-related information about the connection as key/value pairs
The available attributes varies depending on the SSL library being used, and the type of connection.
See also ssl_attribute
# File lib/pg/connection.rb, line 264 def ssl_attributes ssl_attribute_names.each.with_object({}) do |n,h| h[n] = ssl_attribute(n) end end
Returns true
if the connection uses SSL/TLS, false
if not.
Available since PostgreSQL-9.5
static VALUE pgconn_ssl_in_use(VALUE self) { return PQsslInUse(pg_get_pgconn(self)) ? Qtrue : Qfalse; }
Returns status of connection : CONNECTION_OK or CONNECTION_BAD
static VALUE pgconn_status(VALUE self) { return INT2NUM(PQstatus(pg_get_pgconn(self))); }
This function has the same behavior as async_describe_portal
, but is implemented using the synchronous command processing API of libpq. See async_exec
for the differences between the two API variants. It's not recommended to use explicit sync or async variants but describe_portal
instead, unless you have a good reason to do so.
static VALUE pgconn_describe_portal(self, stmt_name) VALUE self, stmt_name; { PGresult *result; VALUE rb_pgresult; t_pg_connection *this = pg_get_connection_safe( self ); const char *stmt; if(NIL_P(stmt_name)) { stmt = NULL; } else { stmt = pg_cstr_enc(stmt_name, this->enc_idx); } result = gvl_PQdescribePortal(this->pgconn, stmt); rb_pgresult = pg_new_result(result, self); pg_result_check(rb_pgresult); return rb_pgresult; }
This function has the same behavior as async_describe_prepared
, but is implemented using the synchronous command processing API of libpq. See async_exec
for the differences between the two API variants. It's not recommended to use explicit sync or async variants but describe_prepared
instead, unless you have a good reason to do so.
static VALUE pgconn_describe_prepared(VALUE self, VALUE stmt_name) { PGresult *result; VALUE rb_pgresult; t_pg_connection *this = pg_get_connection_safe( self ); const char *stmt; if(NIL_P(stmt_name)) { stmt = NULL; } else { stmt = pg_cstr_enc(stmt_name, this->enc_idx); } result = gvl_PQdescribePrepared(this->pgconn, stmt); rb_pgresult = pg_new_result(result, self); pg_result_check(rb_pgresult); return rb_pgresult; }
This function has the same behavior as async_exec
, but is implemented using the synchronous command processing API of libpq. It's not recommended to use explicit sync or async variants but exec
instead, unless you have a good reason to do so.
Both sync_exec
and async_exec
release the GVL while waiting for server response, so that concurrent threads will get executed. However async_exec
has two advantages:
-
async_exec
can be aborted by signals (like Ctrl-C), whileexec
blocks signal processing until the query is answered. -
Ruby VM gets notified about IO blocked operations. It can therefore schedule things like garbage collection, while queries are running like in this proposal: bugs.ruby-lang.org/issues/14723
static VALUE pgconn_exec(int argc, VALUE *argv, VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); PGresult *result = NULL; VALUE rb_pgresult; /* If called with no or nil parameters, use PQexec for compatibility */ if ( argc == 1 || (argc >= 2 && argc <= 4 && NIL_P(argv[1]) )) { VALUE query_str = argv[0]; result = gvl_PQexec(this->pgconn, pg_cstr_enc(query_str, this->enc_idx)); rb_pgresult = pg_new_result(result, self); pg_result_check(rb_pgresult); if (rb_block_given_p()) { return rb_ensure(rb_yield, rb_pgresult, pg_result_clear, rb_pgresult); } return rb_pgresult; } pg_deprecated(0, ("forwarding exec to exec_params is deprecated")); /* Otherwise, just call #exec_params instead for backward-compatibility */ return pgconn_exec_params( argc, argv, self ); }
This function has the same behavior as async_exec_params
, but is implemented using the synchronous command processing API of libpq. See async_exec
for the differences between the two API variants. It's not recommended to use explicit sync or async variants but exec_params
instead, unless you have a good reason to do so.
static VALUE pgconn_exec_params( int argc, VALUE *argv, VALUE self ) { t_pg_connection *this = pg_get_connection_safe( self ); PGresult *result = NULL; VALUE rb_pgresult; VALUE command, in_res_fmt; int nParams; int resultFormat; struct query_params_data paramsData = { this->enc_idx }; /* For compatibility we accept 1 to 4 parameters */ rb_scan_args(argc, argv, "13", &command, ¶msData.params, &in_res_fmt, ¶msData.typemap); paramsData.with_types = 1; /* * For backward compatibility no or +nil+ for the second parameter * is passed to #exec */ if ( NIL_P(paramsData.params) ) { pg_deprecated(1, ("forwarding exec_params to exec is deprecated")); return pgconn_exec( 1, argv, self ); } pgconn_query_assign_typemap( self, ¶msData ); resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt); nParams = alloc_query_params( ¶msData ); result = gvl_PQexecParams(this->pgconn, pg_cstr_enc(command, paramsData.enc_idx), nParams, paramsData.types, (const char * const *)paramsData.values, paramsData.lengths, paramsData.formats, resultFormat); free_query_params( ¶msData ); 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; }
This function has the same behavior as async_exec_prepared
, but is implemented using the synchronous command processing API of libpq. See async_exec
for the differences between the two API variants. It's not recommended to use explicit sync or async variants but exec_prepared
instead, unless you have a good reason to do so.
static VALUE pgconn_exec_prepared(int argc, VALUE *argv, VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); PGresult *result = NULL; VALUE rb_pgresult; VALUE name, in_res_fmt; int nParams; int resultFormat; struct query_params_data paramsData = { this->enc_idx }; rb_scan_args(argc, argv, "13", &name, ¶msData.params, &in_res_fmt, ¶msData.typemap); paramsData.with_types = 0; if(NIL_P(paramsData.params)) { paramsData.params = rb_ary_new2(0); } pgconn_query_assign_typemap( self, ¶msData ); resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt); nParams = alloc_query_params( ¶msData ); result = gvl_PQexecPrepared(this->pgconn, pg_cstr_enc(name, paramsData.enc_idx), nParams, (const char * const *)paramsData.values, paramsData.lengths, paramsData.formats, resultFormat); free_query_params( ¶msData ); 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; }
This function has the same behavior as async_prepare
, but is implemented using the synchronous command processing API of libpq. See async_exec
for the differences between the two API variants. It's not recommended to use explicit sync or async variants but prepare
instead, unless you have a good reason to do so.
static VALUE pgconn_prepare(int argc, VALUE *argv, VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); PGresult *result = NULL; VALUE rb_pgresult; VALUE name, command, in_paramtypes; VALUE param; int i = 0; int nParams = 0; Oid *paramTypes = NULL; const char *name_cstr; const char *command_cstr; int enc_idx = this->enc_idx; rb_scan_args(argc, argv, "21", &name, &command, &in_paramtypes); name_cstr = pg_cstr_enc(name, enc_idx); command_cstr = pg_cstr_enc(command, enc_idx); if(! NIL_P(in_paramtypes)) { Check_Type(in_paramtypes, T_ARRAY); nParams = (int)RARRAY_LEN(in_paramtypes); paramTypes = ALLOC_N(Oid, nParams); for(i = 0; i < nParams; i++) { param = rb_ary_entry(in_paramtypes, i); if(param == Qnil) paramTypes[i] = 0; else paramTypes[i] = NUM2UINT(param); } } result = gvl_PQprepare(this->pgconn, name_cstr, command_cstr, nParams, paramTypes); xfree(paramTypes); rb_pgresult = pg_new_result(result, self); pg_result_check(rb_pgresult); return rb_pgresult; }
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.
static VALUE pgconn_trace(VALUE self, VALUE stream) { VALUE fileno; FILE *new_fp; int old_fd, new_fd; VALUE new_file; t_pg_connection *this = pg_get_connection_safe( self ); if(!rb_respond_to(stream,rb_intern("fileno"))) rb_raise(rb_eArgError, "stream does not respond to method: fileno"); fileno = rb_funcall(stream, rb_intern("fileno"), 0); if(fileno == Qnil) rb_raise(rb_eArgError, "can't get file descriptor from stream"); /* Duplicate the file descriptor and re-open * it. Then, make it into a ruby File object * and assign it to an instance variable. * This prevents a problem when the File * object passed to this function is closed * before the connection object is. */ old_fd = NUM2INT(fileno); new_fd = dup(old_fd); new_fp = fdopen(new_fd, "w"); if(new_fp == NULL) rb_raise(rb_eArgError, "stream is not writable"); new_file = rb_funcall(rb_cIO, rb_intern("new"), 1, INT2NUM(new_fd)); this->trace_stream = new_file; PQtrace(this->pgconn, new_fp); return Qnil; }
Executes a BEGIN
at the start of the block, and a COMMIT
at the end of the block, or ROLLBACK
if any exception occurs.
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; }
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)
static VALUE pgconn_transaction_status(VALUE self) { return INT2NUM(PQtransactionStatus(pg_get_pgconn(self))); }
Returns the connected pgtty. (Obsolete)
static VALUE pgconn_tty(VALUE self) { char *tty = PQtty(pg_get_pgconn(self)); if (!tty) return Qnil; return rb_str_new2(tty); }
Returns the default TypeMap that is currently set for type casts of query bind parameters.
static VALUE pgconn_type_map_for_queries_get(VALUE self) { t_pg_connection *this = pg_get_connection( self ); return this->type_map_for_queries; }
Set the default TypeMap that is used for type casts of query bind parameters.
typemap
must be a kind of PG::TypeMap
.
static VALUE pgconn_type_map_for_queries_set(VALUE self, VALUE typemap) { t_pg_connection *this = pg_get_connection( self ); if ( !rb_obj_is_kind_of(typemap, rb_cTypeMap) ) { rb_raise( rb_eTypeError, "wrong argument type %s (expected kind of PG::TypeMap)", rb_obj_classname( typemap ) ); } Check_Type(typemap, T_DATA); this->type_map_for_queries = typemap; return typemap; }
Returns the default TypeMap that is currently set for type casts of result values.
static VALUE pgconn_type_map_for_results_get(VALUE self) { t_pg_connection *this = pg_get_connection( self ); return this->type_map_for_results; }
Set the default TypeMap that is used for type casts of result values.
typemap
must be a kind of PG::TypeMap
.
static VALUE pgconn_type_map_for_results_set(VALUE self, VALUE typemap) { t_pg_connection *this = pg_get_connection( self ); if ( !rb_obj_is_kind_of(typemap, rb_cTypeMap) ) { rb_raise( rb_eTypeError, "wrong argument type %s (expected kind of PG::TypeMap)", rb_obj_classname( typemap ) ); } Check_Type(typemap, T_DATA); this->type_map_for_results = typemap; return typemap; }
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.
static VALUE pgconn_s_unescape_bytea(VALUE self, VALUE str) { unsigned char *from, *to; size_t to_len; VALUE ret; UNUSED( self ); Check_Type(str, T_STRING); from = (unsigned char*)StringValueCStr(str); to = PQunescapeBytea(from, &to_len); ret = rb_str_new((char*)to, to_len); PQfreemem(to); return ret; }
Disables the message tracing.
static VALUE pgconn_untrace(VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); PQuntrace(this->pgconn); rb_funcall(this->trace_stream, rb_intern("close"), 0); this->trace_stream = Qnil; return Qnil; }
Returns the authenticated user name.
static VALUE pgconn_user(VALUE self) { char *user = PQuser(pg_get_pgconn(self)); if (!user) return Qnil; return rb_str_new2(user); }
Blocks while waiting for notification(s), or until the optional timeout is reached, whichever comes first. timeout is measured in seconds and can be fractional.
Returns nil
if timeout is reached, the name of the NOTIFY event otherwise. If used in block form, passes the name of the NOTIFY event
, the generating pid
and the optional payload
string into the block.
static VALUE pgconn_wait_for_notify(int argc, VALUE *argv, VALUE self) { t_pg_connection *this = pg_get_connection_safe( self ); PGnotify *pnotification; struct timeval timeout; struct timeval *ptimeout = NULL; VALUE timeout_in = Qnil, relname = Qnil, be_pid = Qnil, extra = Qnil; double timeout_sec; rb_scan_args( argc, argv, "01", &timeout_in ); if ( RTEST(timeout_in) ) { timeout_sec = NUM2DBL( timeout_in ); timeout.tv_sec = (time_t)timeout_sec; timeout.tv_usec = (suseconds_t)( (timeout_sec - (long)timeout_sec) * 1e6 ); ptimeout = &timeout; } pnotification = (PGnotify*) wait_socket_readable( this->pgconn, ptimeout, notify_readable); /* Return nil if the select timed out */ if ( !pnotification ) return Qnil; relname = rb_str_new2( pnotification->relname ); PG_ENCODING_SET_NOCHECK( relname, this->enc_idx ); be_pid = INT2NUM( pnotification->be_pid ); if ( *pnotification->extra ) { extra = rb_str_new2( pnotification->extra ); PG_ENCODING_SET_NOCHECK( extra, this->enc_idx ); } PQfreemem( pnotification ); if ( rb_block_given_p() ) rb_yield_values( 3, relname, be_pid, extra ); return relname; }