How to escape strings in SQL Server using PHP?

Question

I\'m looking for the alternative of mysql_real_escape_string() for SQL Server. Is addslashes() my best option or there is another alternative funct

Answer 1

Why would you bother escaping anything when you can use parameters in your query?!

sqlsrv_query(
    $connection, 
    'UPDATE some_table SET some_field = ? WHERE other_field = ?', 
    array($_REQUEST['some_field'], $_REQUEST['id'])
)

It works right in selects, deletes, updates regardless whether your values parameters are null or not. Make a matter of principle - Don't concatenate SQL and you are always safe and your queries read much better.

http://php.net/manual/en/function.sqlsrv-query.php

Answer 2

For the conversion to get the hexadecimal values in SQL back into ASCII, here is the solution I got on this (using the function from user chaos to encode into hexadecimal)

function hexEncode($data) {
    if(is_numeric($data))
        return $data;
    $unpacked = unpack('H*hex', $data);
    return '0x' . $unpacked['hex'];
}

function hexDecode($hex) {
    $str = '';
    for ($i=0; $i<strlen($hex); $i += 2)
        $str .= chr(hexdec(substr($hex, $i, 2)));
    return $str;
}

$stringHex = hexEncode('Test String');
var_dump($stringHex);
$stringAscii = hexDecode($stringHex);
var_dump($stringAscii);

Answer 3

function ms_escape_string($data) {
        if ( !isset($data) or empty($data) ) return '';
        if ( is_numeric($data) ) return $data;

        $non_displayables = array(
            '/%0[0-8bcef]/',            // url encoded 00-08, 11, 12, 14, 15
            '/%1[0-9a-f]/',             // url encoded 16-31
            '/[\x00-\x08]/',            // 00-08
            '/\x0b/',                   // 11
            '/\x0c/',                   // 12
            '/[\x0e-\x1f]/'             // 14-31
        );
        foreach ( $non_displayables as $regex )
            $data = preg_replace( $regex, '', $data );
        $data = str_replace("'", "''", $data );
        return $data;
    }

Some of the code here was ripped off from CodeIgniter. Works well and is a clean solution.

EDIT: There are plenty of issues with that code snippet above. Please don't use this without reading the comments to know what those are. Better yet, please don't use this at all. Parameterized queries are your friends: http://php.net/manual/en/pdo.prepared-statements.php

Answer 4

An answer from 2009-02-22T121000 by user chaos doesn't fit all queries.

For example, "CREATE LOGIN [0x6f6c6f6c6f] FROM WINDOWS" will give you an exception.

PS: look at the SQL Server driver for PHP, http://msdn.microsoft.com/library/cc296181%28v=sql.90%29.aspx and the sqlsrv_prepare function, which can binds parameters.

PSS: Which also didn't help you with the query above ;)

Answer 5

addslashes() isn't fully adequate, but PHP's mssql package doesn't provide any decent alternative. The ugly but fully general solution is encoding the data as a hex bytestring, i.e.

$unpacked = unpack('H*hex', $data);
mssql_query('
    INSERT INTO sometable (somecolumn)
    VALUES (0x' . $unpacked['hex'] . ')
');

Abstracted, that would be:

function mssql_escape($data) {
    if(is_numeric($data))
        return $data;
    $unpacked = unpack('H*hex', $data);
    return '0x' . $unpacked['hex'];
}

mssql_query('
    INSERT INTO sometable (somecolumn)
    VALUES (' . mssql_escape($somevalue) . ')
');

mysql_error() equivalent is mssql_get_last_message().

Answer 6

Another way to handle single and double quotes is:

function mssql_escape($str)
{
    if(get_magic_quotes_gpc())
    {
        $str = stripslashes($str);
    }
    return str_replace("'", "''", $str);
}