Problem with custom permalinks

[kaffeeringe]

I am currently moving my blog (​http://kaffeeringe.de/) to Wordpress and I don't want to break my old URLs (Cool URLs don't change). The problem is, that these custom URLs don't work in Wordpress 3.4.1:

/blog/%postname%/%post_id%.html works
/blog/%postname%.%post_id%.html (which I need) doesn't work.

It doesn't work with the . in between these parameters…

I hope somebody is able to help me.

This isn't a bug - Trac is for submitted bugs in WordPress :)

You should post in the WordPress forums instead (and I would in this case use a .htaccess to parse /blog/%postname%.%post_id%.html into /blog/%postname%/%post_id%/ (or anything else you wanted)

​http://wordpress.org/support if you need more help.

Sounds like a bug to me. We allow random characters in a URL permalink structure, like ".html". Would be interesting to see where and why this fails.

Looks like our support for this is quite tenuous. Many combinations work, but mostly by happenstance.

/%postname%.%post_id%/ fails

/%year%.%monthnum%.%postname%/ works

/%post_id%.%postname%/ works

/%postname%.%year%/ works

Well now that's just odd...

I checked this and found that dot is not escaped when generating rules, e.g.:

  '([^/]+).([0-9]+)(/[0-9]+)?/?$' => 'index.php?name=$1&p=$2&page=$3'

Other special RX chars may also cause problems here - need to check if patch will work with them too.

21167.patch​ is an attempt to escape the special characters which are currently allowed in permalink structure and are acceptable in terms of valid URLs.

Seems to work in the following cases:

/%postname%.%post_id%/
/%postname%+%post_id%/
/%postname%$%post_id%/
/%postname%(%post_id%)/

Is there any reason why we can't just run the permastructure through preg_quote()?

> preg_quote( '.+/()$[]%' );
\.\+/\(\)\$\[\]%

Replying to dd32:

Is there any reason why we can't just run the permastructure through preg_quote()?

Thanks, that indeed makes more sense.

Unit test

Unit test added, 21167.2.patch​ looks good. Let me know if there are any test cases missing.

@kurtpayne - was that unit test patch committed?

​[UT1113]

[22365]

The fix is probably incomplete. We should be passing the second argument on preg_quote and use the same delimiter where rewrite rules are being used.

For example, having the following permalink structure "/%post_id%#foo" (yes, probably unrealistic) would produce an invalid regular expression in wp-includes/class-wp.php, where # is used as a delimiter.
http://core.trac.wordpress.org/browser/trunk/wp-includes/rewrite.php#L344
http://core.trac.wordpress.org/browser/trunk/wp-includes/class-wp.php#L204

Seems to me like this should be preg_quote()'d before getting used in a regexp, rather than on save.

Using preg_quote() breaks rewrites for post types with hyphens. I'm not entirely sure how supported that is to begin with, but I know I need to convert a few now. :)

In 22403:

Revert [22365]. see #21167