Apache rewrite rules

Avoid escaping URLs in Apache rewrite rules

Today we started hacking some Apache rewrite rules to make some URLs a little more friendly. All of the URLs we are rewriting are entry points for our application, which in the WO world means direct actions.

All of them contain queries parts. These are the arguments in a URL, like http://domain.com/something?arg=value&anotherArg=anotherValue. Well, everything was running fine until we accessed an URL with a escaped character. We had the following rule:

RewriteRule ^/optOut(.*) /cgi-bin/WebObjects/OurApp.woa/wa/optOut$1 [R]

When we tried to access the URL http://domain.com/optOut?email=me%40domain.com, we got:


Note the last part or the URL. The problem is that the original % in %40 (the escape code for @) was being itself escaped, leading to a corrupt URL. The result of calling formValueForKey on this was me%40domain.com.

After googling for a while, I found out many people have this problem, but surprisingly I could not find a decent solution. I saw hacks with escape internal functions and PHP weird variables that obviously wouldn’t help me at all, and I was starting to get nervous.

Well, while reading the rewrite module documentation, I found the solution right there: the NE option. According to the docs:

‘noescape|NE’ (no URI escaping of output)
This flag prevents mod_rewrite from applying the usual URI escaping rules to the result of a rewrite. Ordinarily, special characters (such as ‘%’, ‘$’, ‘;’, and so on) will be escaped into their hexcode equivalents (‘%25’, ‘%24’, and ‘%3B’, respectively); this flag prevents this from happening. This allows percent symbols to appear in the output(…)

Well, this is it. I saw so many pages with people asking about this problem without getting any answers that I was not very confident on this, but I tried to change the rule for:

RewriteRule ^/optOut(.*) /cgi-bin/WebObjects/OurApp.woa/wa/optOut$1 [R,NE]

And that’s it. It’s now working as it should, producing the correct URL:


Apparently, it’s that simple.