[wp-trac] [WordPress Trac] #12271: Using # in permalinks breaks preg_match in parse_request

[WordPress Trac]

#12271: Using # in permalinks breaks preg_match in parse_request
--------------------------+-------------------------------------------------
 Reporter:  timsogard     |       Owner:  ryan      
     Type:  defect (bug)  |      Status:  new       
 Priority:  normal        |   Milestone:  Unassigned
Component:  Permalinks    |     Version:  2.9.2     
 Severity:  normal        |    Keywords:            
--------------------------+-------------------------------------------------
 When using a hash symbol (#) in a custom permalink structure the
 parse_request function fails with the error "Unmatched modifier". This is
 due to the pattern being delimited by hash symbols (#s).

 The call to preg_match is on lines 210 and 211 in wp-includes/classes.php:

 {{{
    if (preg_match("#^$match#", $request_match, $matches) ||
       preg_match("#^$match#", urldecode($request_match), $matches)) {
       // Got a match.

 }}}

 Suggested, probably weak as it's been a while for me and PHP, fix:

 Using str_replace on '#'s into '\#'s.

 {{{
    if (preg_match("#^" . str_replace("#","\#",$match) . "#",
 $request_match, $matches) ||
       preg_match("#^" . str_replace("#","\#",$match) . "#",
 urldecode($request_match), $matches)) {
       // Got a match.

 }}}

 I am using hashes in my URLs because I am loading my WP blog with an ajax
 loader (it loads in a div).

 Other possible fixes I don't have the werewithall to test(/benchmark) at
 the moment:

 use a symbol from the intersection of the sets of "may show up in a URL"
 and "is a valid PCRE pattern delimeter" as the pattern delimeter.

 wrap $match in preg_quote, which will properly escape any of the regular
 expression syntax chars ($, *, ?, etc.)

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Ticket URL: <http://core.trac.wordpress.org/ticket/12271>
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