Question

In the following code, what does the regex do?

RewriteCond   %{REQUEST_URI}       ^/(?:[A-Za-z]+(?:/[A-Za-z]*)*)(?:/\d+)?$
RewriteRule   .*                   var/www/%1/index.php [L]

What is the outcome of the re-wrtie rule?

Thanks, I am helping a friend fix an old CMS and I don’t know why whomever made it did this.

Answer 1

What is the outcome of the re-write rule?

AFAIK it will generate 404s when you don’t expect it to. Why?

1. The (?: something) brackets are basically the same as () except that they don’t set a match variable. Since all bracketing is like this %1 will never be defined.

2. Picking up Alexander’s description /letters{/letters}([/digits]) where the /digits are optional. The repeat group is “zero or more letters” and hence will eat any / characters, and these are greedy matches, so /aa/bb/cc/123 will be parsed as (/aa)(/bb)(/cc)(/)(123). This will fail since 123 does not match (?:/\d+)?

3. So it will only match alpha path strings, e.g. /aaa/bbb/ccc and %1 will be “” and in these circumstances this will redirect to var/www//index.php relative to the current path, which will probably be the DOCROOT, so unless DOCROOT/var/www/index.php exists, this will result in a 404.