Name
    xss-nginx-module - Native cross-site scripting support in nginx

Synopsis

   # accessing /foo?callback=process gives the response
   # body "process(...);" (without quotes) where "..."
   # is the original response body of the /foo location.
   server {
        location /foo {
            # your content handler goes here...

            xss_get on;
            xss_callback_arg 'callback';
            xss_input_types 'application/json'; # default
            xss_output_type 'application/x-javascript'; # default
        }
        ...
    }

Description
    This module adds cross-site AJAX support to nginx. Currently only
    cross-site GET is supported. But cross-site POST will be added
    in the future.

    The cross-site GET is currently implemented as JSONP
    (or "JSON with padding"). See <http://en.wikipedia.org/wiki/JSON#JSONP >
    for more details.

Directives
    * xss_get on | off
        Syntax: xss_get on | off
        Default: xss_get off
        Context: main, http, location, if location

        Enable JSONP support for GET requests.

    * xss_callback_arg
        Syntax: xss_callback_arg <name>
        Default: none
        Context: main, http, location, if location

        Specify the JavaScript callback function name
        used in the responses.

        For example,

            location /foo {
                xss_get on;
                xss_callback_arg c;
                ...
            }

        then

            GET /foo?c=blah

        returns

            blah(...);

    * xss_override_status
        Syntax: xss_override_status on | off
        Default: xss_check_status on
        Context: main, http, location, if location

        Whether to override 30x, 40x and 50x status to 200
        when the response is actually being processed.

    * xss_check_status
        Syntax: xss_check_status on | off
        Default: xss_check_status on
        Context: main, http, location, if location

        By default, ngx_xss only process responses with the status code
        200 or 201.

    * xss_input_types
        Syntax: xss_input_types [mime-type]...
        Default: xss_input_types application/json
        Context: main, http, location, if location

        Only processes the responses of the specified MIME types.

        Example:
            xss_input_types application/json text/plain;

Limitations
    *   ngx_xss will not work with ngx_echo's subrequest interfaces, due to the underlying
        limitations imposed by subrequests' "postponed chain" mechanism in the nginx core.
        The standard ngx_addition module also falls into this category.  You're recommended,
        however, to use ngx_lua as the content handler to issue subrequests *and* ngx_xss
        to do JSONP, because ngx_lua's ngx.location.capture() interface does not utilize the
        "postponed chain" mechanism, thus getting out of this limitation. We're taking this
        approach in production and it works great.

Trouble Shooting
    Use the "info" error log level (or lower) to get more
    diagnostics when things go wrong.

Installation
    Grab the nginx source code from nginx.net (<http://nginx.net/>), for
    example, the version 1.4.3 (see nginx compatibility), and then build
    the source with this module:

        $ wget 'http://nginx.org/download/nginx-1.4.3.tar.gz'
        $ tar -xzvf nginx-1.4.3.tar.gz
        $ cd nginx-1.4.3/

        # Here we assume you would install you nginx under /opt/nginx/.
        $ ./configure --prefix=/opt/nginx \
            --add-module=/path/to/xss-nginx-module

        $ make -j2
        $ make install

    Download the latest version of the release tarball of this module from
    xss-nginx-module file list
    (<http://github.com/agentzh/xss-nginx-module/tags>).

Compatibility
    The following versions of Nginx should work with this module:

    *   1.4.x (last tested: 1.4.3)

    *   1.2.x (last tested: 1.2.9)

    *   1.0.x (last tested: 1.0.10)

    *   0.9.x (last tested: 0.9.4)

    *   0.8.x (last tested: 0.8.54)

    *   0.7.x >= 0.7.30 (last tested: 0.7.67)

    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 0.7.30 does not
    work with this module, please consider reporting a bug.

TODO
    *   add cross-site POST support.

Known Issues

See Also

    * Introduction to JSONP ( http://en.wikipedia.org/wiki/JSONP )
    * ngx_drizzle ( http://github.com/chaoslawful/drizzle-nginx-module )

Author
    agentzh (章亦春) <agentzh at gmail dot com>

Copyright & License
    The implementation of the builtin connection pool has borrowed
    a lot of code from Maxim Dounin's upstream_keepalive module.
    This part of code is copyrighted by Maxim Dounin.

    This module is licenced under the BSD license.

    Copyright (C) 2009-2011 by Zhang "agentzh" Yichun (章亦春) <agentzh@gmail.com>.

    All rights reserved.

    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.
