Why does this pattern not match QUERY_STRING in RewriteCond while it matches in preg_match?

Question

Here is what I have in my .htaccess file.

RewriteEngine on

RewriteCond %{QUERY_STRING}  ^(run=[a-z0-9A-z]{13})$
RewriteRule %{QUERY_STRING}  \? [L]

All I am doing is Rewriting the QUERY_STRING for all QUERY_STRING similar to run=4f13665700694 and do nothing. A URL example: http://thinkingmonkey.me/runs/?run=4f13665700694. So, the RewriteCond should Match. But the above does not work.

But, the pattern seemed correct. Since, both preg_match & RewriteRule use PCRE - Perl Compatible Regular Expressions.

I tried it using preg_match.

$subject = "run=4f13665700694"; 
$pattern = "/^(run=[a-z0-9A-z]{13})$/";

echo preg_match($pattern, $subject);

And as excepted the above will output:

1

i.e. a successful match.

I do not understand why. What am I missing here?

Answer 1

Ok, so, this will take a request to /runs/ with the 13-character alphanumeric run parameter as the only thing in its query string, strip the query string, and rewrite to /runs/index.php:

RewriteCond %{QUERY_STRING} ^run=\w{13}$
RewriteRule ^/runs/?$ /runs/index.php? [L]