Question

These rewrite rules don’t seem to work. Is it just not possible or am I missing something

The problematic rule is the second one, notice the back-reference %1

RewriteCond %{REQUEST_URI} ^/([a-zA-Z\.]+)/.*$ [NC]
RewriteCond %{HTTP_COOKIE} route_controller_%1=([^;]+) [NC]
RewriteRule ^(.*)$ http://example2.com/%1/_/$1 [L]

This is what I am expecting to happen. Given the URL

http://example.com/abc/home

The first rule should store abc in %1
I want the second rule for a cookie called route_controller_abc and if found
Then the third rule would rewite to

http://example2.com/thevalueofthecookie/_/home

But the seconf rule doesn’t seem to be using the %1 back-reference.

Any Ideas?

Answer 1

The reason for this is that string substitution only occurs in the first parameter on a cond and not on its rexexp. You have to do a hack to simulate parameters in regexps using \1 etc.

You can also pick up the directory in the rule regexp, since the execution order is rule regexp, cond1, cond2,… rule substitution. eg. ^(*.?)/.*$ for abc/homewill set $1 to abc and $0 to abc/home. Hence I would try something like:

RewriteCond $1:%{HTTP_COOKIE} ^(.*?):.*\broute_controller_\1=([^;]+) [NC]
RewriteRule ^(*.?)/.*$        http://example2.com/%2/_/$0            [L]

Note that the controller is now in %2 as %1 is used to bind the directory in the cond regexp.

Hope this helps and answers your direct Q. Hovever, I would be a little twitchy using unvalidated cookies like this for redirection. If I were doing this I would either tighten the validation of the parameter ([^;]+) or move this to a small PHP redirector script and do the validation there 🙂