mod_rewrite number of parameters/back-references limitation

Question

Apparently there is a limitation (9) on how many backreferences you can access in htaccess RewriteRules..

But we have a RewriteRule that requires more than 9 paramet

Answer 1

Actually, you don't need to capture everything. Write non-capturing groups (introduced with "?:") for the things you don't want to reuse, this should give you some breathing space again. Compare:

Yours:                       Mine:
-------------------------    ---------------------------
^([^/]+)/b          $1       ^([^/]+)/b            $1
([0-9]+)            $2       ([0-9]+)              $2
(/a([0-9]+))?       $4       (?:/a([0-9]+))?       $3
(/v([0-9]+))?       $6       (?:/v([0-9]+))?       $4
(,([0-9]+))?        $8       (?:,([0-9]+))?        $5
(/(ajax|share))?    $10!     (?:/(ajax|share))?    $6
(,complete)?$       $11!     (,complete)?$         $7

But with mod_rewrite alone, you can't go higher than 9 back-references. If you need more, use an alternative - for example capturing only the most important parts in rewrite and do some string-processing with the rest of the URL in your app.