Name
ngx_headers_more - Set and clear input and output headers...more than
"add"!
*This module is not distributed with the Nginx source.* See the
installation instructions.
Version
This document describes headers-more-nginx-module v0.14
(<http://github.com/agentzh/headers-more-nginx-module/downloads >)
released on January 25, 2011.
Synopsis
# set the Server output header
more_set_headers 'Server: my-server';
# set and clear output headers
location /bar {
more_set_headers 'X-MyHeader: blah' 'X-MyHeader2: foo';
more_set_headers -t 'text/plain text/css' 'Content-Type: text/foo';
more_set_headers -s '400 404 500 503' -s 413 'Foo: Bar';
more_clear_headers 'Transfer-Encoding' 'Content-Type';
# your proxy_pass/memcached_pass/or any other config goes here...
}
# set output headers
location /type {
more_set_headers 'Content-Type: text/plain';
# ...
}
# set input headers
location /foo {
set $my_host 'my dog';
more_set_input_headers 'Host: $my_host';
more_set_input_headers -t 'text/plain' 'X-Foo: bah';
# now $host and $http_host have their new values...
# ...
}
# replace input header X-Foo *only* if it already exists
more_set_input_headers -r 'X-Foo: howdy';
Description
This module allows you to add, set, or clear any output or input header
that you specify.
This is an enhanced version of the standard headers module because it
provides more utilities like resetting or clearing "builtin headers"
like "Content-Type", "Content-Length", and "Server".
It also allows you to specify an optional HTTP status code criteria
using the "-s" option and an optional content type criteria using the
"-t" option while modifying the output headers with the more_set_headers
and more_clear_headers directives. For example,
more_set_headers -s 404 -t 'text/html' 'X-Foo: Bar';
Input headers can be modified as well. For example
location /foo {
more_set_input_headers 'Host: foo' 'User-Agent: faked';
# now $host, $http_host, $user_agent, and
# $http_user_agent all have their new values.
}
The option "-t" is also available in the more_set_input_headers and
more_clear_input_headers directives (for request header filtering) while
the "-s" option is not allowed.
Unlike the standard headers module, this module's directives will by
default apply to all the status codes, including "4xx" and "5xx".
Directives
more_set_headers
syntax: *more_set_headers [-t <content-type list>]... [-s <status-code
list>]... <new-header>...*
default: *no*
context: *http, server, location, location if*
Adds or replaces the specified output headers when the response status
code matches the codes specified by the "-s" option *AND* the response
content type matches the types specified by the "-t" option.
If either "-s" or "-t" is not specified or has an empty list value, then
no match is required. Therefore, the following directive set the
"Server" output header to the custom value for *any* status code and
*any* content type:
more_set_headers "Server: my_server";
A single directive can set/add multiple output headers. For example
more_set_headers 'Foo: bar' 'Baz: bah';
Multiple occurrences of the options are allowed in a single directive.
Their values will be merged together. For instance
more_set_headers -s 404 -s '500 503' 'Foo: bar';
is equivalent to
more_set_headers -s '404 500 503' 'Foo: bar';
The new header should be the one of the forms:
1. "Name: Value"
2. "Name: "
3. "Name"
The last two effectively clear the value of the header "Name".
Nginx variables are allowed in header values. For example:
set $my_var "dog";
more_set_headers "Server: $my_var";
But variables won't work in header keys due to performance
considerations.
Multiple set/clear header directives are allowed in a single location,
and they're executed sequentially.
Directives inherited from an upper level scope (say, http block or
server blocks) are executed before the directives in the location block.
Note that although "more_set_headers" is allowed in *location* if
blocks, it is *not* allowed in the *server* if blocks, as in
? # This is NOT allowed!
? server {
? if ($args ~ 'download') {
? more_set_headers 'Foo: Bar';
? }
? ...
? }
Behind the scene, use of this directive and its friend
more_clear_headers will (lazily) register an ouput header filter that
modifies "r->headers_out" the way you specify.
more_clear_headers
syntax: *more_clear_headers [-t <content-type list>]... [-s <status-code
list>]... <new-header>...*
default: *no*
context: *http, server, location, location if*
Clears the specified output headers.
In fact,
more_clear_headers -s 404 -t 'text/plain' Foo Baz;
is exactly equivalent to
more_set_headers -s 404 -t 'text/plain' "Foo: " "Baz: ";
or
more_set_headers -s 404 -t 'text/plain' Foo Baz
See more_set_headers for more details.
Wildcard "*" can also be used to specify a header name pattern. For
example, the following directive effectively clears *any* output headers
starting by ""X-Hidden-"":
more_clear_headers 'X-Hidden-*';
The "*" wildcard support was first introduced in v0.09.
more_set_input_headers
syntax: *more_set_input_headers [-r] [-t <content-type list>]...
<new-header>...*
default: *no*
context: *http, server, location, location if*
Very much like more_set_headers except that it operates on input headers
(or request headers) and it only supports the "-t" option.
Behind the scene, use of this directive and its friend
more_clear_input_headers will (lazily) register a "rewrite phase"
handler that modifies "r->headers_in" the way you specify. Note that it
always run at the *end* of the "rewrite" so that it runs *after* the
standard rewrite module and works in subrequests as well.
If the "-r" option is specified, then the headers will be replaced to
the new values *only if* they already exist.
more_clear_input_headers
syntax: *more_clear_input_headers [-t <content-type list>]...
<new-header>...*
default: *no*
context: *http, server, location, location if*
Clears the specified input headers.
In fact,
more_clear_input_headers -s 404 -t 'text/plain' Foo Baz;
is exactly equivalent to
more_set_input_headers -s 404 -t 'text/plain' "Foo: " "Baz: ";
or
more_set_input_headers -s 404 -t 'text/plain' Foo Baz
See more_set_input_headers for more details.
Limitations
* Unlike the standard headers module, this module does not
automatically take care of the constraint among the "Expires",
"Cache-Control", and "Last-Modified" headers. You have to get them
right yourself or use the headers module together with this module.
Installation
Grab the nginx source code from nginx.net (<http://nginx.net/ >), for
example, the version 0.8.54 (see nginx compatibility), and then build
the source with this module:
$ wget 'http://sysoev.ru/nginx/nginx-0.8.54.tar.gz'
$ tar -xzvf nginx-0.8.54.tar.gz
$ cd nginx-0.8.54/
# Here we assume you would install you nginx under /opt/nginx/.
$ ./configure --prefix=/opt/nginx \
--add-module=/path/to/headers-more-nginx-module
$ make -j2
$ make install
Download the latest version of the release tarball of this module from
headers-more-nginx-module file list
(<http://github.com/agentzh/headers-more-nginx-module/downloads >).
Compatibility
The following versions of Nginx should work with this module:
* 1.0.x (last tested: 1.0.2)
* 0.9.x (last tested: 0.9.4)
* 0.8.x (last tested: 0.8.54)
* 0.7.x >= 0.7.44 (last tested: 0.7.68)
Earlier versions of Nginx like 0.6.x and 0.5.x will *not* work.
If you find that any particular version of Nginx above 0.7.44 does not
work with this module, please consider reporting a bug.
Report Bugs
Although a lot of effort has been put into testing and code tuning,
there must be some serious bugs lurking somewhere in this module. So
whenever you are bitten by any quirks, please don't hesitate to
1. send a bug report or even patches to <agentzh@gmail.com>,
2. or create a ticket on the issue tracking interface
(<http://github.com/agentzh/headers-more-nginx-module/issues >)
provided by GitHub.
Source Repository
Available on github at agentzh/headers-more-nginx-module
(<http://github.com/agentzh/headers-more-nginx-module >).
ChangeLog
v0.14
* now we postpone the rewrite phase handler only once rather than on
every main request previously. this will save some CPU cycles on
every request if more_set_input_headers or more_clear_input_headers
are used.
* fixed two spots where we did not check against null pointers when
out of memory.
* now we use the 2-clause bsd license instead.
* various coding style fixes.
v0.13
* fixed a bug in rewrite phase postponing algorithm which may cause
ngx_eval (<http://www.grid.net.ru/nginx/eval.en.html >)'s eval block
running *after* ngx_rewrite
(<http://wiki.nginx.org/NginxHttpRewriteModule >)'s directives.
thanks Liseen Wan (xunxin).
v0.12
* fixed a bug in the Content-Type output header setting handler. we
should always clear "r->headers_out.content_type_lowcase", or it'll
confuse output filters like that of the gzip module.
v0.11
* fixed the variables-in-Range-header issue in more_set_input_headers
reported by Alexander Vetrin.
v0.10
* now we can remove an input and output header *completely*, including
both custom and builtin headers.
v0.09
* fixed a memory initialization issue for more_set_input_headers
without the "-r" option, we should always initialize "hv.replace"
even when replace == 0. This may result in server segfaults and was
introduced in v0.08.
* implemented wildcard support in more_clear_headers. Thanks Bernd
Dorn.
v0.08
* applied the patch from Bernd Dorn to add the "-r" option to the
more_set_input_headers directive.
v0.07
* fixed the more_clear_headers directive for builtin headers like
"Server" and "Last-Modified" by always inserting an empty header
when absent. Thanks Sebastiaan Deckers for reporting it.
v0.06
* now the input header handler runs at the *end* of the "rewrite
phase" such that it works in subrequests by default.
v0.05
* fixed variables in more_set_input_headers by registering the handler
in the "access phase" instead of the "rewrite" phase.
Test Suite
This module comes with a Perl-driven test suite. The test cases
(<http://github.com/agentzh/headers-more-nginx-module/tree/master/t/ >)
are declarative
(<http://github.com/agentzh/headers-more-nginx-module/blob/master/t/sani
ty.t>) too. Thanks to the Test::Nginx
(<http://search.cpan.org/perldoc?Test::Nginx >) module in the Perl world.
To run it on your side:
$ PATH=/path/to/your/nginx-with-headers-more-module:$PATH prove -r t
To run the test suite with valgrind's memcheck, use the following
commands:
$ export PATH=/path/to/your/nginx-with-headers-more-module:$PATH
$ TEST_NGINX_USE_VALGRIND=1 prove -r t
You need to terminate any Nginx processes before running the test suite
if you have changed the Nginx server binary.
Because a single nginx server (by default, "localhost:1984") is used
across all the test scripts (".t" files), it's meaningless to run the
test suite in parallel by specifying "-jN" when invoking the "prove"
utility.
Some parts of the test suite requires modules proxy, rewrite, and echo
to be enabled as well when building Nginx.
TODO
* Support variables in new headers' keys.
Getting involved
You'll be very welcomed to submit patches to the author or just ask for
a commit bit to the source repository on GitHub.
Authors
agentzh (章亦春) *<agentzh@gmail.com>*
Bernd Dorn ( http://www.lovelysystems.com/ )
This wiki page is also maintained by the author himself, and everybody
is encouraged to improve this page as well.
Copyright & License
The code base is borrowed directly from the standard headers module in
Nginx 0.8.24. This part of code is copyrighted by Igor Sysoev.
Copyright (c) 2009, 2010, 2011, Taobao Inc., Alibaba Group (
http://www.taobao.com ).
Copyright (c) 2009, 2010, 2011, Yichun "agentzh" Zhang (章亦春)
<agentzh@gmail.com>.
Copyright (c) 2010, 2011, Bernd Dorn.
This module is licensed under the terms of the BSD license.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
See Also
* The original thread on the Nginx mailing list that inspires this
module's development: "A question about add_header replication"
(<http://forum.nginx.org/read.php?2,11206,11738 >).
* The orginal announcement thread on the Nginx mailing list: "The
"headers_more" module: Set and clear output headers...more than
'add'!" (<http://forum.nginx.org/read.php?2,23460 >).
* The original blog post
(<http://agentzh.blogspot.com/2009/11/headers-more-module-scripting-
input-and.html>) about this module's initial development.
* The echo module for Nginx module's automated testing.
* The standard headers module.