To set RequestHeader in apache httpd server is not working

apache-2.2httpd.confmod-proxymod-rewriterewritecond

I have a requirement, where I need to set the RequestHeader with a value retrieved from the querystring of the URI.

Approach adopted is to write the RewriteCond and ReWriteRule where
the condition is to extract value from %{QUERYSTRING} variable and set this into another Environment variable and later refer this and add it to request header.

But this doesn't seem to be working for me. I am using Apache 2.2 on RHEL.

My httpd configuration placed in one of .conf file is as below.

RewriteCond %{QUERY_STRING} ^(\w+)=(\w+)$
RewriteRule . - [E=RU:%1]
Header set "X-Header" "%{RU}e" env=RU

NOTE: I also tried to set the request header by hard coding the value and I also have proxy module enabled.

RequestHeader set X-User-ID "test"
Header append X-test %{RU}e
RequestHeader set X-UserID %{RU}e early

Using "early" option also didn't help.

Best Answer

In your original configuration you are using Header instead of RequestHeader. Header sets a response header not a request header.

I've tested it by adding the logging of the X-header HTTP header to the access log format, and it works fine. The only thing I've changed is the . to a ^ in the RewriteRule

RewriteEngine On
RewriteCond %{QUERY_STRING} ^(\w+)=(\w+)$
RewriteRule ^ - [E=RU:%1]
RequestHeader set "X-Header" "%{RU}e" env=RU

How are you testing the header has been set?

Related Solutions

Apache mod_rewrite, using current URL in RewriteCond

You can access the "current" URI via a backreference. From the RewriteRule documentation...

TestString is a string which can contain the following expanded constructs in addition to plain text:

RewriteRule backreferences: These are backreferences of the form $N (0 <= N <= 9), which provide access to the grouped parts (in parentheses) of the pattern, from the RewriteRule which is subject to the current set of RewriteCond conditions.

You can handle the initial slash more cleanly too — the request URI always starts with a /. (The shortest request you can make is GET / HTTP/1.0.) The solution is...

# Map '/' to '/home'
RewriteRule ^/$ /home

# Check for cached page
RewriteCond %{DOCUMENT_ROOT}/system/cache/$1.html -f
RewriteRule ^/(.+)$ /system/cache/$1.html [QSA,L]

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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Apache mod_rewrite, using current URL in RewriteCond

Tomcat – Apache2 – mod_expire and mod_rewrite not working in httpd.conf – serving content from tomcat

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