Customize HTTP-headers (  %{HTTP:header}  )

Posted on 2002-07-26
Last Modified: 2010-03-04


I have some customized HTTP-headers that I want to use. I send information about the user and want to change the URL dependin on this header. I have found that I can use
RewriteRule and use %{HTTP:header} (unfortunalty that only works on the ordinary headers like Host, Location).
RewriteRule ^/(.*) /%{HTTP:MyHeader}/$1
doesn't work, output is

RewriteRule ^/(.*) /%{HTTP:host}/$1
output is

is there anyway I can add these headers in apache so it
finds them. (does this make sense?)
or should I be using a perl-script instead? I'm not that good at perl scripts though.

Question by:M031097
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LVL 15

Expert Comment

ID: 7184566

Taka a look at mod_headers module.

And subsequently, you can use you cgi scripts, or SSI to examine this header and act accordingly.


Author Comment

ID: 7184600
Hi Samri

mod_headers seems to be for adding, removing headers not getting their values.

Regarding I said, not that good at them. Guess I have to learn that too then.

LVL 15

Expert Comment

ID: 7184641

depending on what you want to do; I am afraid that you might have to start working on CGI scripts.  With CGI, you can even sent HTTP header on response to client request.

mod_rewrite can do it, but I doesn't have that much knowledge (too tricky to work on.).

If you insist on working on mod_rewrite, please take a look at Rewriting Guide on Apache website.

There is a number of examples that make use of HTTP Header.  Perhaps on would match what you intend to use.

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Author Comment

ID: 7184655

yes I have been looking at the Rewriting Guide, but haven't found anything on getting the value of a header that I have set. Still loking though...

LVL 51

Expert Comment

ID: 7184798
hat do you want to do with the HEADER information?
Is it just to controll the URL, then mod_env and mod_setenv might be what you're looking for.

Something like:

     SetEnvIf Request_URI "/whatever/"  myvariable
and then in <Directory>

     Allow from all env=myvariable
LVL 15

Expert Comment

ID: 7184856

Please taka a look at mod_rewrite docs;

Some example;

RewriteCond  %{HTTP_USER_AGENT}  ^Mozilla.*
RewriteRule  ^/$                 /homepage.max.html  [L]

RewriteCond  %{HTTP_USER_AGENT}  ^Lynx.*
RewriteRule  ^/$                 /homepage.min.html  [L]

RewriteRule  ^/$                 /homepage.std.html  [L]

Also take a look at how you could try something with module;

Author Comment

ID: 7184893

No, I want to get the value of a specific header (that I have inserted previously). Even if I kan use SetEnvIf and find the header, I cannot get the value of the header (if I understand it correctly)

I have looked at the documents, but nothing helps (at least not what I've found)
Like I said, the header I am looking for is something I have added, so the ordinary pre-defined headers doesn't help.
I can use HTTP:<then the header name> to find the headers and I thought I could find my own header as well, but unfortunatly it didn't work
RewriteRule ^/(.*) /%{HTTP:MyHeader}/$1
doesn't work, output is

notice the // at the end, compared to below:

RewriteRule ^/(.*) /%{HTTP:host}/$1
output is

where it inserted:
LVL 27

Accepted Solution

BigRat earned 200 total points
ID: 7304829
According to the mod-rewrite docu :-

There is the special format: %{HTTP:header} where header can be any HTTP MIME-header name. This is looked-up from the HTTP request. Example: %{HTTP:Proxy-Connection} is the value of the HTTP header ``Proxy-Connection:''.

Your header is NOT a standard MIME header. In CGI such no standard headers are prefixed with HTTP_

From :

In addition to these, the header lines received from the client, if any, are placed into the environment with the prefix HTTP_ followed by the header name. Any - characters in the header name are changed to _ characters. The server may exclude any headers which it has already processed, such as Authorization, Content-type, and Content-length. If necessary, the server may choose to exclude any or all of these headers if including them would exceed any system environment limits.

LVL 15

Expert Comment

ID: 9691105
No comment has been added lately, so it's time to clean up this TA.

I will leave a recommendation in the Cleanup topic area with the following recommendation for this question:

Answered by BigRat

Please leave any comments here within the next seven days.


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