How to fetch HTTP headers in perl when using CGI

Question

I'm using Perl/CGI/Apache and want to fetch the X-Forwarded-For HTTP header. How do I do that?

score 16 · Accepted Answer · answered Feb 09 '11 at 19:27

16

Except for a few headers that are handled specially, CGI stores the value of Header-Name: in the environment variable HTTP_HEADER_NAME. So, X-Forwarded-For (if present in the request) should be found in $ENV{HTTP_X_FORWARDED_FOR}.

answered Feb 09 '11 at 19:27

cjm

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@cjm, thank you so much. Is there any rfc or protocol or standard defines, web server passes http header to cgi process in environment variables way with prefix HTTP_? – http8086 May 15 '18 at 12:13
@hylepo, [RFC 3875](https://tools.ietf.org/html/rfc3875#section-4.1.18) – cjm Jun 25 '18 at 19:58

score 5 · Answer 2 · edited Oct 05 '12 at 09:39

5

CGI has a method for accessing HTTP request header fields, called "http", so you can say:

my $q = CGI->new()
print $q->http('X-Forwarded-For');

This works regardless whether you're running as a CGI, in fastcgi, mod_perl, etc...

edited Oct 05 '12 at 09:39

Rup

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answered Mar 07 '12 at 13:31

mephinet

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How to fetch HTTP headers in perl when using CGI

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