pg_unescape_bytea

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

pg_unescape_bytea — Unescape binary for bytea type

Description

function pg_unescape_bytea(string $string): string

pg_unescape_bytea() unescapes PostgreSQL bytea data values. It returns the unescaped string, possibly containing binary data.

Note:

When you SELECT a bytea type, PostgreSQL returns octal byte values prefixed with '\' (e.g. \032). Users are supposed to convert back to binary format manually.

Parameters

string

A string containing PostgreSQL bytea data to be converted into a PHP binary string.

Return Values

A string containing the unescaped data.

Examples

Example #1 pg_unescape_bytea() example

<?php 
  // Connect to the database
  $dbconn = pg_connect('dbname=foo');
  
  // Get the bytea data
  $res = pg_query("SELECT data FROM gallery WHERE name='Pine trees'");  
  $raw = pg_fetch_result($res, 'data');
  
  // Convert to binary and send to the browser
  header('Content-type: image/jpeg');
  echo pg_unescape_bytea($raw);
?>

See Also

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User Contributed Notes 2 notes

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5
liviu dot mirea at gmail dot com
15 years ago
PostgreSQL 9.0 introduced "hex" as the new default format for encoding binary data. Because "pg_unescape_bytea" only works with the old "escape" format, you need to do pg_query('SET bytea_output = "escape";'); before executing your select queries.

More details can be found here: http://www.postgresql.org/docs/9.0/static/datatype-binary.html

[Ed: Recent PostgreSQL versions support unescaping the "hex" format.]
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0
muralito at montevideo dot com dot uy
15 years ago
The workaround is to configure a property in the postgres database for the user, to make postgres behave as the old default.

ALTER USER username SET bytea_output = 'escape';

(or using the pgadmin interface)
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