©
本文檔使用 php中文網手册 發布
(PHP 4 >= 4.2.0, PHP 5)
pg_escape_bytea — 转义 bytea 类型的二进制数据
$data
)pg_escape_bytea() 转义 bytea 数据类型的二进制字符串,返回转义后的字符串。
Note:
当对 bytea 类型字段进行 SELECT 操作时,PostgreSQL 返回前导 \ 的八进制字节值(例如 \032)。用户需要自己将结果转换为二进制格式。
本函数需要 PostgreSQL 7.2 或以上版本。在 PostgreSQL 7.2.0 和 7.2.1 版中,如果使用了多字节支持,bytea 类型必须被强制转换。例如 INSERT INTO test_table (image) VALUES ('$image_escaped'::bytea);。PostgreSQL 7.2.2 或以上版本不需要强制转换。异常情况是当客户端和后端字符编码不匹配时,可能会有多字节流错误。用户必须强制转换 bytea 以避免此错误。
参见 pg_unescape_bytea() 和 pg_escape_string() 。
[#1] Michael [2014-03-12 15:10:39]
using pg_escape_bytea without 'E' escape tag
<?php
// Die Bin?rdaten maskieren
$escaped = pg_escape_bytea($data);
// und in die Datenbank einf??gen (falsch/wrong)
pg_query("INSERT INTO gallery (name, data) VALUES ('Pine trees', E'$escaped')");
// und in die Datenbank einf??gen (richtig/right)
pg_query("INSERT INTO gallery (name, data) VALUES ('Pine trees', '$escaped')");
?>
[#2] Mike-RaWare [2010-07-08 02:03:33]
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);
?>
[#3] gglockner AT NOSPAMdwaffler DOT com [2009-07-17 14:13:51]
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)");
?>
[#4] ynzhang from lakeheadu of ca [2009-02-18 13:44:48]
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));
$original_data = pg_unescape_bytea($escaped_data));
?>
more details at: http://archives.postgresql.org/pgsql-php/2007-02/msg00014.php
[#5] Mocha [2003-08-07 17:20:07]
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) {
$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;
}
?>
[#6] php at tobias dot olsson dot be [2002-08-17 09:56:25]
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