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I'm trying to redirect all requests to my domain to another domain using mod_rewrite in an Apache 2.2 VirtualHost declaration. There is one exception to this -- I'd like all requests to the /audio path not to be redirected.

I've written a RewriteCond and RewriteRule to do this but it's not quite right and I can't figure out why. The regular expression contains a negative lookahead for the string "/audio", but for some reason this isn't matching. Here's the definition:

RewriteEngine on
RewriteCond %{HTTP_HOST} ^(.*\.)?mydomain\.net(?!/audio) [NC]
RewriteRule ^(.*)$ http://www.newdomain.example [L,R=301]

If I change the RewriteCond to:

RewriteCond %{HTTP_HOST} ^(.*\.)?mydomain\.example/(?!audio) [NC]

(i.e. put the forward slash outside of the negative lookahead part) then it works, but the downside of this is that requests to mydomain.example without a trailing slash will not be redirected.

Can anyone point out what I'm doing wrong?

Here are the rules:

<VirtualHost *:80>
ServerAdmin me@mydomain.example
DocumentRoot "/var/www/mydomain.example/htdocs"
ServerName www.mydomain.example
ServerAlias mydomain.example

RewriteEngine on
RewriteCond {REQUEST_URI} !^/audio
RewriteRule ^(.*)$ http://www.newdomain.example [L,R=301]
RewriteLog logs/mod_rewrite_log
RewriteLogLevel 3

ErrorLog logs/error_log
CustomLog logs/access_log common
</VirtualHost>

Thanks @mercutio -- that makes perfect sense but it still doesn't seem to work.

Here's what the mod_rewrite log says when I make a request to http://mydomain.example/audio/something.mp3:

(2) init rewrite engine with requested uri /audio/something.mp3
(3) applying pattern '^(.*)$' to uri '/audio'
(2) rewrite '/audio' -> 'http://www.newdomain.example/'
(2) explicitly forcing redirect with http://www.newdomain.example
(1) escaping http://www.newdomain.example for redirect
(1) redirect to http://www.newdomain.example [REDIRECT/301]

Since the REQUEST_URI does start with /audio I would expect the RewriteRule to be ignored.

Stephen Ostermiller
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Olly
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  • applying pattern '^(.*)$' to uri '/audio' Sounds like it's processing a different pattern. Or perhaps the logic is just backwards now. Can you post your full set of rules? – mercutio Aug 21 '08 at 09:33

1 Answers1

49

The HTTP_HOST only contains the host name, not the path of the URL requested.

RewriteCond %{REQUEST_URI} !^/audio

Should be all you need.

Further, you can get debug info from the rewrite engine with the following, which is really useful to see how your conditions and rules are being matched:

RewriteLog /path/to/log/file
RewriteLogLevel 3
Goran Jovic
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mercutio
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  • Update: the RewriteCond is still correct, but in versions of apache >= 2.4, RewriteLog no longer works. You can set Loglevel specific to mod_rewrite with 'LogLevel rewrite:trace3' but then need to watch the ErrorLog for output. – mightypile Dec 07 '17 at 13:28