php-doc-en/reference/pgsql/functions/pg-unescape-bytea.xml

<?xml version="1.0" encoding="utf-8"?>
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<!-- splitted from ./en/functions/pgsql.xml, last change in rev 1.61 -->
<refentry xml:id='function.pg-unescape-bytea' xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>pg_unescape_bytea</refname>
  <refpurpose>
   Unescape binary for bytea type
  </refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>string</type><methodname>pg_unescape_bytea</methodname>
   <methodparam><type>string</type><parameter>data</parameter></methodparam>
  </methodsynopsis>
  <para>
   <function>pg_unescape_bytea</function> unescapes PostgreSQL bytea data
   values.  It returns the unescaped string, possibly containing binary data.
  </para>
  <note>
   <para>
    When you <literal>SELECT</literal> a bytea type, PostgreSQL returns octal byte values
    prefixed with '\' (e.g. \032). Users are supposed to convert back to
    binary format manually.
   </para>
   <para>
    This function requires PostgreSQL 7.2 or later. With PostgreSQL
    7.2.0 and 7.2.1, bytea values must be cast when you enable
    multi-byte support. i.e. <literal>INSERT INTO test_table (image)
    VALUES ('$image_escaped'::bytea);</literal> PostgreSQL 7.2.2 or
    later does not need a cast. The exception is when the client and backend
    character encoding does not match, and there may be multi-byte
    stream error. User must then cast to bytea to avoid this error.
   </para>
  </note>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>data</parameter></term>
     <listitem>
      <para>
       A <type>string</type> containing PostgreSQL bytea data to be converted into
       a PHP binary string.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   A <type>string</type> containing the unescaped data.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>pg_unescape_bytea</function> example</title>
    <programlisting role="php">
<![CDATA[
<?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);
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry>5.5.1</entry>
       <entry>
        A warning is thrown if the input string is invalid.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>pg_escape_bytea</function></member>
    <member><function>pg_escape_string</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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