pg_escape_bytea

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

pg_escape_bytea — Escape a string for insertion into a bytea field

Опис

pg_escape_bytea(PgSql\Connection $connection = ?, string $data): string

pg_escape_bytea() escapes string for bytea datatype. It returns escaped string.

Зауваження:
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.

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. INSERT INTO test_table (image) VALUES ('$image_escaped'::bytea); 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.

Параметри

connection

Примірник PgSql\Connection. Якщо параметр connection не визначено, то виконується стандартне з'єднання, тобто останнє, виконане функцією pg_connect() або pg_pconnect().

Увага

Починаючи з PHP 8.1.0, використання стандартного з'єднання є застарілим.

data

A string containing text or binary data to be inserted into a bytea column.

Значення, що повертаються

A string containing the escaped data.

Журнал змін

Версія	Опис
8.1.0	Тепер параметр `connection` має бути примірником PgSql\Connection. Раніше очікувався resource.

Приклади

Приклад #1 pg_escape_bytea() example

<?php 
  // Connect to the database
  $dbconn = pg_connect('dbname=foo');
  
  // Read in a binary file
  $data = file_get_contents('image1.jpg');
  
  // Escape the binary data
  $escaped = pg_escape_bytea($data);
  
  // Insert it into the database
  pg_query("INSERT INTO gallery (name, data) VALUES ('Pine trees', '{$escaped}')");
?>

Прогляньте також

pg_unescape_bytea() - Unescape binary for bytea type
pg_escape_string() - Escape a string for query

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User Contributed Notes 8 notes

down

ynzhang from lakeheadu of ca ¶

15 years ago

The reason pg_unescape_bytea() do not exactly reproduce the binary data created by pg_escape_bytea() is because the backslash \ and single quote ' are double escaped by the pg_escape_bytea() function. This will lead to image seems corrupted when retrieve from the bytea field. The proper way to escape&unescape a binary string into a PG bytea field as follow:



<?php

$escaped_data = str_replace(array("\\\\", "''"), array("\\", "'"), pg_escape_bytea($data));

/* and later unescape the escaped data from the bytea field with following to get the original binary data */



$original_data = pg_unescape_bytea($escaped_data));

?>



more details at: http://archives.postgresql.org/pgsql-php/2007-02/msg00014.php

down

Hayley Watson ¶

7 years ago

PostgreSQL 9.0 introduced a new hexadecimal-based representation for bytea data that is preferred over the escaping mechanism implemented by this function.

<?php
function pg_escape_byteahex($binary)
{
    return "E'\\\\x".bin2hex($binary)."'";
}
?>

down

Mike-RaWare ¶

14 years ago

To prevent any problems with encoding you could use hexadecimal or base64 input to save and retrieve data to the database:

<?php 
  // Connect to the database
  $dbconn = pg_connect( 'dbname=foo' );
  
  // Read in a binary file
  $data = file_get_contents( 'image1.jpg' );
  
  // Escape the binary data
  $escaped = bin2hex( $data );
  
  // Insert it into the database
  pg_query( "INSERT INTO gallery (name, data) VALUES ('Pine trees', decode('{$escaped}' , 'hex'))" );

  // Get the bytea data
  $res = pg_query("SELECT encode(data, 'base64') AS 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 base64_decode($raw);
?>

down

Mocha ¶

21 years ago

to unescape_bytea use stripcslashes(). If you need to escape bytea and don't have pg_escape_bytea() function then use:



<?php

function escByteA($binData) {

  /**

   * \134 = 92 = backslash, \000 = 00 = NULL, \047 = 39 = Single Quote

   *

   * str_replace() replaces the searches array in order. Therefore, we must

   * process the 'backslash' character first. If we process it last, it'll

   * replace all the escaped backslashes from the other searches that came

   * before.

   */

  $search = array(chr(92), chr(0), chr(39));

  $replace = array('\\\134', '\\\000', '\\\047');

  $binData = str_replace($search, $replace, $binData);

  return $binData;

  //echo "<pre>$binData</pre>";

  //exit;

}

?>

down

tabflo at gmx dot at ¶

3 months ago

this method des the same as pg_escape_bytea have fun with it:

public function escape_bytea($data) {
        $escaped = '';

        for ($i = 0; $i < strlen($data); $i++) {
            $char = $data[$i];
            $ascii = ord($char);

            $escaped.= ($ascii < 32 || $ascii > 126 ? sprintf('\\%03o', $ascii) : ($char == '\\' ? '\\\\' : $char) );
        }
        return $escaped;
    }

down

Michael ¶

10 years ago

using  pg_escape_bytea without 'E' escape tag
<?php 
  // Die Binärdaten maskieren
  $escaped = pg_escape_bytea($data);

  // und in die Datenbank einfügen (falsch/wrong)
  pg_query("INSERT INTO gallery (name, data) VALUES ('Pine trees', E'$escaped')");

  // und in die Datenbank einfügen (richtig/right)
  pg_query("INSERT INTO gallery (name, data) VALUES ('Pine trees', '$escaped')");
?>

down

gglockner AT NOSPAMdwaffler DOT com ¶

15 years ago

If you're getting errors about nonstandard use of \\ in a string literal, then you need to escape the encoded bytea as follows:



<?php

$escaped = pg_escape_bytea($data);

pg_query("INSERT INTO gallery (name, data) VALUES ('Pine trees', E'$escaped'::bytea)");

?>

down

-3

php at tobias dot olsson dot be ¶

22 years ago

if you need to change back bytea from the db to normal data, this will do that:



<?php

function pg_unescape_bytea($bytea) {

return eval("return \"".str_replace('$', '\\$', str_replace('"', '\\"', $bytea))."\";");

}



// use like this

$rs = pg_query($conn, "SELECT image from images LIMIT 1");

$image = pg_unescape_bytea(pg_fetch_result($rs, 0, 0));

?>



/Tobias

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