.. Licensed to the Apache Software Foundation (ASF) under one
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   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
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.. include:: ../../../../common.defs

.. _developer-plugins-examples-basic-auth:

Basic Authorization Plugin
**************************

The sample basic authorization plugin, ``basic_auth.c``, checks for
basic HTTP proxy authorization. In HTTP basic proxy authorization,
client user names and passwords are contained in the
``Proxy-Authorization`` header. The password is encoded using base64
encoding. The plugin checks all incoming requests for the authorization
header, user name, and password. If the plugin does not find all of the
these, then it reenables with an error (effectively stopping the
transaction) and adds a transaction hook to the send response header
event.

Creating the Plugin's Parent Continuation and Global Hook
=========================================================

The parent continuation and global hook are created as follows:

``TSHttpHookAdd (TS_HTTP_OS_DNS_HOOK, TSContCreate (auth_plugin, NULL));``

.. important::

   Authorization plugins which attach to :c:data:`TS_HTTP_OS_DNS_HOOK` (as shown in
   the example above) will not operate as expected unless
   :ts:cv:`proxy.config.http.doc_in_cache_skip_dns` is set to ``0``. Disabling
   this feature ensures that DNS hooks will still be executed even when a
   matching document has been located in the cache. The downside is that the
   performance gain by skipping otherwise unnecessary DNS lookups is lost.

.. toctree::
   :maxdepth: 2

   implementing-the-handler-and-getting-a-handle-to-the-transaction.en
   working-with-http-headers.en
   setting-a-transaction-hook.en
