WordPress – How to set an environment variable based on pre-rewritten URI or post-rewritten query parameter

.htaccessapache-2.2gziprewriteWordpress

So there's a file in WordPress, wp-content/blogs.php, that serves files uploaded through WordPress. There's a RewriteRule in the WP .htaccess that rewrites URLs of the format www.example.com/files/11/01/filename.mp3 to URLs of the format www.example.com/.../wp-content/blogs.php?file=filename.mp3.

RewriteRule ^(.*/)?files/(.*) wp-content/blogs.php?file=$2 [L]

So here's the problem: we have gzip turned on for PHP files. I need to turn it off based on the query parameter file, on blogs.php. (Not just because you're not supposed to gzip binaries, but because gzipping .mp3 creates severe problems for the Quicktime plugin in Firefox on both PC and Mac.)

But the following SetEnvIf isn't applied to any files served through blogs.php – the Request_URI always ends in .php.

SetEnvIfNoCase Request_URI \.mp3$ no-gzip dont-vary

The following fixes the problem by turning off gzip on all files served through blogs.php:

<Location /michael/blah/wp-content/blogs.php>        
     SetEnv no-gzip
</Location>

But it's not a good solution, because I want non-binary files served through blogs.php to be gzipped. So what I really want is a way to get the original URI, not the rewritten URI, because the original URI does end in .mp3. Or, I need to access the query parameter at the end of the rewritten URI (ie. file=filename.mp3).

For instance, something like this would work, if it existed, which it doesn't:

SetEnvIfNoCase Original_Request_URI \.mp3$ no-gzip dont-vary

It looks like there's a variable THE_REQUEST that would work in a RewriteRule, but it doesn't seem available to SetEnvIf.

Any ideas?

Best Answer

You can manipulate the environment from mod_rewrite, including turning off gzip:

RewriteCond %{QUERY_STRING} file=(.*)\.mp3$
RewriteRule ^(./)?files/(.) wp-content/blogs.php?file=$2 [L,E=no-gzip:1]

The first RewriteCond may not be necessary, but the last rule (the E flag) should do the trick in your setup regardless.

HTH.

Related Solutions

Windows – Content Encoding Error when trying to use GZip on Apache

The first issue is that you have the element with a directory from the file system...

This is from the Apache manual:

When to use <Location>. Use <Location> to apply directives to content that lives outside the filesystem. For content that lives in the filesystem, use <Directory> and <Files>. An exception is <Location />, which is an easy way to apply a configuration to the entire server.

When I setup mod_deflate on Apache I use this setup:

# --------------------------------------------------------
# Deflate Module Configuration
# --------------------------------------------------------
<IfModule deflate_module>
  # Set the location to webservers root
  <Location />
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    # Netscape 4.x has some problems
    BrowserMatch ^Mozilla/4 gzip-only-text/html
    # Netscape 4.06-4.08 have some more problems
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    # Make sure proxies don't deliver the wrong content
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    SetEnvIfNoCase Request_URI \.(?:exe|t?gz|zip|bz2|sit|rar)$ no-gzip dont-vary
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    # Enable mod_deflate logging by uncommenting these lines
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Tomcat – Apache2 – mod_expire and mod_rewrite not working in httpd.conf – serving content from tomcat

Probably the ProxyPass / directive you have in your config routes all requests to the Tomcat backend, bypassing all your mod_rewrite directives. You can try to remove the ProxyPass directive and use RewriteRule with the [P] flag after your other rewrites:

mod_rewrite: P|proxy

For the expire headers the situation is worse — in another similar question a solution was not found.

Option +FollowSymLinks would be needed for using mod_rewrite in .htaccess files; in your case it is not required, because you can put everything in the Apache config. Moving rules from config to .htaccess is pointless and can only make things slower. However, there is an important difference between .htaccess and the Apache config — in .htaccess patterns in RewriteRule are matched against relative filesystem paths (which never start with /), while in the VirtualHost context these patterns are matched against the URL path after the hostname, which always starts with /. Therefore at least one of your rules is incorrect:

RewriteRule ^content/(js|css)/([a-z]+)-([0-9]+)\.(js|css)$ /content/$1/$2.$4

should be

RewriteRule ^/content/(js|css)/([a-z]+)-([0-9]+)\.(js|css)$ /content/$1/$2.$4

(note the additional slash in the beginning).

Best Answer

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