.. Licensed to the Apache Software Foundation (ASF) under one
   or more contributor license agreements.  See the NOTICE file
   distributed with this work for additional information
   regarding copyright ownership.  The ASF licenses this file
   to you under the Apache License, Version 2.0 (the
   "License"); you may not use this file except in compliance
   with the License.  You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing,
   software distributed under the License is distributed on an
   "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   KIND, either express or implied.  See the License for the
   specific language governing permissions and limitations
   under the License.

.. include:: ../../common.defs

.. _admin-plugins:

Plugins
*******

.. toctree::
   :maxdepth: 2

Overview
========

One of the key features of |ATS| is its modularity. Features that aren't needed
in the core simply aren't there. This helps to provide an additional guarantee
that our core can remain fast by concentrating on the things that we always
provide: caching and proxying.

All other functionality can be moved into plugins and by offering a consistent
C API, everyone can implement their own functionality, without having to touch
the core.

Stable plugins
==============

Plugins that are considered stable are installed by default in |TS| releases.

.. toctree::
   :hidden:

   AWS S3 Authentication <s3_auth.en>
   AuthProxy <authproxy.en>
   Background Fetch <background_fetch.en>
   Cache Key Manipulation <cachekey.en>
   Cache Promotion Policies <cache_promote.en>
   Combo Handler <combo_handler.en>
   Configuration Remap <conf_remap.en>
   ESI <esi.en>
   Escalate <escalate.en>
   Compress <compress.en>
   Generator <generator.en>
   Header Rewrite <header_rewrite.en>
   Health Checks <healthchecks.en>
   Lua <lua.en>
   Regex Remap <regex_remap.en>
   Regex Revalidate <regex_revalidate.en>
   Remap Purge <remap_purge.en>
   Stats over HTTP <stats_over_http.en>
   TCPInfo <tcpinfo.en>
   XDebug <xdebug.en>

:doc:`AuthProxy <authproxy.en>`
   Delegates the authorization decision of a request to an external HTTP service.

:doc:`AWS S3 Authentication <s3_auth.en>`
   Support for Amazon S3 authentication features.

:doc:`Background Fetch <background_fetch.en>`
   Proactively fetch content from Origin in a way that it will fill the object into cache.

:doc:`Cache Key Manipulation <cachekey.en>`
   Allows some common cache key manipulations based on various HTTP request elements.

:doc:`Cache Promotion Policies <cache_promote.en>`
   Allows for control over which assets should be written to cache, or not.

:doc:`Combo Handler <combo_handler.en>`
   Provides an intelligent way to combine multiple URLs into a single URL, and have Apache Traffic Server combine the components into one response.

:doc:`Configuration Remap <conf_remap.en>`
    Override configuration directives on a per-rule basis.

:doc:`ESI <esi.en>`
   Implements the Edge Side Includes (ESI) specification.

:doc:`Escalate <escalate.en>`
   Escalate: when the origin returns specific status codes, retry the request at a secondary origin (failover/fail-action)

:doc:`Generator <generator.en>`
   Generate arbitrary response data.

:doc:`Compress <compress.en>`
    Compress or deflate cache responses.

    .. sidebar: Formerly "gzip".

:doc:`Header Rewrite <header_rewrite.en>`
    Modify requests and responses based on incoming and outgoing headers and
    other transaction attributes.

:doc:`Health Checks <healthchecks.en>`
    Define service health check links.

:doc:`Lua <lua.en>`
   Allows plugins to be written in Lua instead of C code.

:doc:`Regex Remap <regex_remap.en>`
    Configure remapping rules using regular expressions.

:doc:`Regex Revalidate <regex_revalidate.en>`
   Configurable rules for forcing cache object revalidations using regular expressions.

:doc:`Stats over HTTP <stats_over_http.en>`
    Provide an HTTP interface to all |TS| statistics.

:doc:`TCPInfo <tcpinfo.en>`
    Log TCP metrics at various points of the HTTP processing pipeline.

:doc:`XDebug <xdebug.en>`
   Allows HTTP clients to debug the operation of the Traffic Server cache using the X-Debug header.

Experimental plugins
====================

Plugins that are considered experimental are located in the
`plugins/experimental <https://git-wip-us.apache.org/repos/asf?p=trafficserver.git;a=tree;f=plugins/experimental;hb=HEAD>`_
directory of the |TS| source tree. Experimental plugins can be compiled by passing the
`--enable-experimental-plugins` option to `configure`::

    $ autoconf -i
    $ ./configure --enable-experimental-plugins
    $ make

.. toctree::
   :hidden:

   Access Control <access_control.en>
   Balancer <balancer.en>
   Buffer Upload <buffer_upload.en>
   Certifier <certifier.en>
   Collapsed-Forwarding <collapsed_forwarding.en>
   GeoIP ACL <geoip_acl.en>
   FQ Pacing <fq_pacing.en>
   Header Frequency <header_freq.en>
   HIPES <hipes.en>
   Hook Trace <hook-trace.en>
   Memcache <memcache.en>
   Metalink <metalink.en>
   Money Trace <money_trace.en>
   MP4 <mp4.en>
   MySQL Remap <mysql_remap.en>
   Signed URLs <url_sig.en>
   SSL Headers <sslheaders.en>
   Stale While Revalidate <stale_while_revalidate.en>
   System Statistics <system_stats.en>
   Traffic Dump <traffic_dump.en>
   WebP Transform <webp_transform.en>
   Prefetch <prefetch.en>

:doc:`Access Control <access_control.en>`
   Access control plugin that handles various access control use-cases.

:doc:`Balancer <balancer.en>`
   Balances requests across multiple origin servers.

:doc:`Buffer Upload <buffer_upload.en>`
   Buffers POST data before connecting to the Origin server.

:doc:`Certifier <certifier.en>`
   Manages and/or generates certificates for incoming HTTPS requests.

:doc:`Collapsed-Forwarding <collapsed_forwarding.en>`
   Allows to Collapse multiple Concurrent requests by downloading once from the Origin and serving
   all clients in parallel.

:doc:`FQ Pacing <fq_pacing.en>`
   FQ Pacing: Rate Limit TCP connections using Linux's Fair Queuing queue discipline

:doc:`GeoIP ACL <geoip_acl.en>`
   Deny or allow requests based on the source IP geo-location.

:doc:`Header Frequency <header_freq.en>`
   Count the frequency of headers.

:doc:`HIPES <hipes.en>`
   Adds support for HTTP Pipes.

:doc:`Memcache <memcache.en>`
   Implements the memcache protocol for cache contents.

:doc:`Metalink <metalink.en>`
   Implements the Metalink download description format in order to try not to download the same file twice.

:doc:`Money Trace <metalink.en>`
   Allows Trafficserver to participate in a distributed tracing system based upon the Comcast Money library.

:doc:`MP4 <mp4.en>`
   MP4 streaming media.

:doc:`MySQL Remap <mysql_remap.en>`
   Allows dynamic remaps from a MySQL database.

:doc:`Remap Purge <remap_purge.en>`
   This remap plugin allows the administrator to easily setup remotely
   controlled ``PURGE`` for the content of an entire remap rule.

:doc:`Signed URLs <url_sig.en>`
   Adds support for verifying URL signatures for incoming requests to either deny or redirect access.

:doc:`SSL Headers <sslheaders.en>`
   Populate request headers with SSL session information.

:doc:`Stale While Revalidate <stale_while_revalidate.en>`
   :deprecated:

   Refresh content asynchronously while serving stale data.

:doc:`System Stats <system_stats.en>`
    Inserts system statistics in to the stats list

:doc:`Traffic Dump <traffic_dump.en>`
   Dumps traffic data into a JSON format file which can be used to replay traffic.

:doc:`WebP Transform <webp_transform.en>`
   Converts jpeg and png images to webp format.
