defined search term(s) for query
For a search feature I wrote a MySQL query to be executed by a PHP script. I'm not doing a fulltext search. Instead, I'm doing a search using the following method:
... WHERE field LIKE '%etc%' AND field REGEXP '[[:<:]]etc[[:>:]]'
Now, my idea is to prepare these dynamic values in PHP, like:
$word = '2*3%5_1^0'; // just an example
$wordLike = strtr($word,array(''=>'\','%'=>'%','_'=>'_'));
// instead of my old solution:
// $wordLike = preg_replace('~([%_])~', '\$1', $word);
$wordLike = $db_con->escape('%' . $wordLike . '%');
$spaces = '[[:blank:]]|[[:punct:]]|[[:space:]]';
// I'm not sure about the difference between blank & space, though
$wordRX = preg_quote($word);
$wordRX = $db_con->escape('(^|'.$spaces.')'.$wordRX.'($|'.$spaces.')');
// instead of my old solution:
// $wordRX = $db_con->escape('[[:<:]]' . $wordRX . '[[:>:]]');
and then use these values like in…
... WHERE field LIKE '$wordLike' AND field REGEXP '$wordRX'
which, with this example input, results in
...
WHERE field LIKE '%2*3%5_1^0%' AND
field REGEXP '[[:<:]]2*3%5_1^0[[:>:]]`
A couple of notes…
LIKE
& REGEXP
together- was the fastest one among the approaches I tried. Q1: Is this the right way to go?
Q2: Is this secure enough against SQL injections?
Some additional info
About MySQL REGEXP
…
Following characters are escaped by preg_quote()
. + * ? [ ^ ] $ ( ) { } = ! < > | : -
Following is the list of [occasionally] special characters in REGEXP
. + * ? [ ^ ] $ ( ) { } | -
There are also additional constructs in REGEXP
but they're all surrounded by single/double brackets, and because I know all the brackets will be escaped by preg_quote() I feel like I shouldn't be concerned about them.
About MySQL LIKE
…
The only 2 special characters in LIKE
are
_ %
So escaping them seems enough a workaround.
Please correct me if I'm missing anything.
Appart from what you mention mysql_real_escape_string() function should do fine for sanitization against SQL injection.
You just have to properly escape whatever user input using the appropiate escaping function(s), if you picture it as chained processing blocks processing this user input you will know in which order (from last to first) and what to escape/unescape and when, and you should be okay as far as securing a clean input goes (validation is a different issue).
And, as you already seem to know, quote() on PDO or Mysqli prepare() are a better approach.
试试这个使用mysql_real_escape_string()
$word = '2*3%5_1^0';
$query = 'SELECT * FROM TABLE_NAME WHERE field REGEXP "(.*)[[:<:]]'.mysql_real_escape_string($word).'[[:>:]](.*)" ';
function clean($str) {
$str = @trim($str);
if(get_magic_quotes_gpc()) {
$str = stripslashes($str);
}
return mysql_real_escape_string($str);
}
then:
$word = clean($_POST['whatever post']);
then trim word and your good to go. what this php function does is take all literals and turns them into strings so no one can lets say delete your db etc
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