SQL Injection, is this effective?

[kevinkorb]

Is this effective in preventing SQL injections.. it seems like it would be to me.  What would make this not generally ideal to do before entering user submitted data into the database?

[code]
<?php
Class Filter {
  public static function clean_array($array) {
    foreach($array AS $key => $val) {
        $array[$key] = mysqli_real_escape_string($val);
    }
  }
}

// Then cleaning the post array.

$clean = Filter::clean_array($_POST);

$query = "INSERT INTO table (f1,f2,f3) VALUES ('{$clean['f1']'}, '{$clean['f2']'}, '{$clean['f3']'});";
mysqli_query($db, $query);

?>
[/code]

[Daniel0]

Looks fine to me.

Consider this though:

[code]<?php
$clean = array_map('mysql_real_escape_string',$_POST);

$query = "INSERT INTO table (f1,f2,f3) VALUES ('{$clean['f1']}', '{$clean['f2']}', '{$clean['f3']}');";
mysqli_query($db, $query);

?>[/code]

[kevinkorb]

Ya, but the good thing about the other one is you can litter that all throughout your project.  If you find a better escaping method you can just change the 'clean_array()' method once to use whatever logic you'd use to clean all your arrays.

Abstraction

But I you made a good point with the array_map function. 

So change the class to be
[code]
<?php
Class Filter {
  public static function clean_array($array) {
    return array_map('mysql_real_escape_string', $array);
  }
}
?>
[/code]

[Daniel0]

Yeah, well... that was my point. I supposed you were able to figure it out yourself (which you did).

[Eric_Ryk]

Though that does work it is probably also a good idea to make sure that you are only getting the characters that you are supposed to using regular expressions.

[Daniel0]

mysql_real_escape_string() gets all the characters that causes a security risk. An important thing to note is that the characters % and _ which are considered as wildcards if combined with GRANT, LIKE and REVOKE will not be escaped so if you are going to put a string into a such query you must manually escape those characters as well.