pg_escape_bytea

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

    pg_escape_bytea — 转义字符串以插入到 bytea 字段

    说明

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

    pg_escape_bytea() 转义 bytea 数据类型的字符串。返回转义后的字符串。

    注意:

    当 SELECT bytea 类型时，PostgreSQL 返回前缀为“\”的八进制字节值（例如 \032）。用户需要手动转换为二进制格式。

    本函数需要 PostgreSQL 7.2 及其更高版本。在 PostgreSQL 7.2.0 和 7.2.1 版中，如果使用了多字节支持，必须强制转换 bytea 类型。即 INSERT INTO test_table (image) VALUES ('$image_escaped'::bytea);，在 PostgreSQL 7.2.2 及其更高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。然后用户必须强制转换 bytea 以避免此错误。

    参数

    connection

    An PgSql\Connection instance. When connection is unspecified, the default connection is used. The default connection is the last connection made by pg_connect() or pg_pconnect().

    警告

    As of PHP 8.1.0, using the default connection is deprecated.

    data

    包含要插入到 bytea 列中的文本或二进制数据的 string。

    返回值

    包含转义数据的 string。

    更新日志

    版本 说明
    8.1.0 现在 connection 参数接受 PgSql\Connection 实例，之前接受 resource。

    示例

    示例 #1 pg_escape_bytea() 示例

    <?php
    // 连接到数据库
    $dbconn = pg_connect('dbname=foo');

    // 读入二进制文件
    $data = file_get_contents('image1.jpg');

    // 转义二进制数据
    $escaped = pg_escape_bytea($data);

    // 将其插入数据库
    pg_query("INSERT INTO gallery (name, data) VALUES ('Pine trees', '{$escaped}')");
    ?>

    参见

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    用户贡献的备注 8 notes

    up
    8
    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
    up
    4
    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)."'";
    }
    ?>
    up
    3
    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);
    ?>
    up
    1
    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;
    }
    ?>
    up
    0
    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;
    }
    up
    0
    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')");
    ?>
    up
    0
    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)");
    ?>
    up
    -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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