pg_escape_string

(PHP 4 >= 4.2.0, PHP 5)

pg_escape_string — Escape a string for insertion into a text field

Description

string pg_escape_string ([ resource $connection ], string $data )

pg_escape_string() escapes a string for insertion into the database. It returns an escaped string in the PostgreSQL format. Use of this function is recommended instead of addslashes(). If the type of the column is bytea, pg_escape_bytea() must be used instead.

Note: This function requires PostgreSQL 7.2 or later.

Parameters

connection: PostgreSQL database connection resource. When connection is not present, the default connection is used. The default connection is the last connection made by pg_connect() or pg_pconnect().
data: A string containing text to be escaped.

Return Values

A string containing the escaped data.

ChangeLog

Version	Description
5.2.0	`connection` added

Examples

Example #1 pg_escape_string() example


<?php 
  // Connect to the database
  $dbconn = pg_connect('dbname=foo');
  
  // Read in a text file (containing apostrophes and backslashes)
  $data = file_get_contents('letter.txt');
  
  // Escape the text data
  $escaped = pg_escape_string($data);
  
  // Insert it into the database
  pg_query("INSERT INTO correspondence (name, data) VALUES ('My letter', '{$escaped}')");
?>


If your database is a UTF-8 database, you will run into problems trying to add some data into your database...





for securty issues and/or compatability you may need to use the: utf_encode() (http://php.net/utf8-encode) function.





for example:


<?php


$my_data = pg_escape_string(utf8_encode($_POST['my_data']));


?>

Gautam Khanna
29-Aug-2007 04:55


Security methods which you use depend on the specific purpose. For those who dont know, take a look at the following built-in PHP functions:



strip_tags()            to remove HTML characters

(also see htmlspecialchars)



escapeshellarg()      to escape shell commands etc

escapeshellcmd()



mysql_real_escape_string()     to escape mySQL commands.



Enjoy!



web dot expert dot panel at gmail dot com

Gautam Khanna
29-Aug-2007 04:54


Security methods which you use depend on the specific purpose. For those who dont know, take a look at the following built-in PHP functions:



strip_tags()            to remove HTML characters

(also see htmlspecialchars)



escapeshellarg()      to escape shell commands etc

escapeshellcmd()



mysql_real_escape_string()     to escape mySQL commands.



Enjoy!



web dot expert dot panel at gmail dot com

johniskew2 at yahoo dot com
30-May-2006 06:43


For those who escape their single quotes with a backslash (ie \') instead of two single quotes in a row (ie '') there has recently been a SERIOUS sql injection vulnerability that can be employed taking advantage of your chosen escaping method.  More info here: http://www.postgresql.org/docs/techdocs.50

Even after the postgre update, you may still be limited to what you can do with your queries if you still insist on backslash escaping. It's a lesson to always use the PHP functions to do proper escaping instead of adhoc addslashes or magic quotes escaping.

meng
28-May-2006 01:21


Since php 5.1 the new function pg_query_params() was introduced. With this function you can use bind variables and don't have to escape strings. If you can use it, do so. If unsure why, check the changelog for Postgres 8.0.8.

otix
25-Apr-2006 12:43


Creating a double-tick is just fine. It works the same as the backslash-tick syntax. From the PostgreSQL docs:



The fact that string constants are bound by single quotes presents an obvious semantic problem, however, in that if the sequence itself contains a single quote, the literal bounds of the constant are made ambiguous. To escape (make literal) a single quote within the string, you may type two adjacent single quotes. The parser will interpret the two adjacent single quotes within the string constant as a single, literal single quote. PostgreSQL will also allow single quotes to be embedded by using a C-style backslash.

dominik dot mueller at access dot unizh dot ch
15-Jan-2006 06:40


in reply to "rich at dicksonlife dot com"



use serialize() / unserialize() instead!

rich at dicksonlife dot com
19-Jul-2005 02:38


Here's some code I knocked up to turn an array of values into a string representation of an array. Note that I also add the external single quotes to make it a full string literal.



  //$t is array to be escaped. $u will be string literal.

  $tv=array();

  foreach($t as $key=>$val){

    $tv[$key]="\"" . 

      str_replace("\"",'\\"', str_replace('\\','\\\\',$val)) . "\"

";

  }

  $u= implode(",",$tv) ;

  $u="'{" . pg_escape_string($u) . "}'";



There's probably a better way of doing this. That's why I'm posting this here :)

tsharek at o2 dot pl
02-Mar-2005 12:34


IMO the stripslashes in this case is not very usefull. Because pg_escape_string change ' into '' (double ' - not "). I use in add to database this:

pg_escape_string(stripslashes($_GET['var'])) and is in 100% safe (i hope).



If I use addslashes in this case that well be lost space in database (\''' - this is 3 bytes)



ps. sorry for my english:)

16-Jul-2003 08:30


Here with 'abc'efg'  the middle ' terminates the string, however 'abc\'def' is one big string with a ' character in the middle.



If the user can terminate the string he can then put in the bad sql.  When prompted for Barcode the user could put in  DROP TABLE foo; SELECT '1



$query = sprintf ("SELECT * FROM a.tblcards WHERE barcode='%s'", pg_escape_string($barcode)); 



So you have to "clean" your variable coming in to prevent that.

add a note

pg_execute

pg_escape_bytea

Last updated: Fri, 05 Sep 2008