.. Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed
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   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
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.. include:: ../../../common.defs

.. default-domain:: cpp

TSHttpTxnClientStreamPriorityGet
********************************

Synopsis
========

.. code-block:: cpp

    #include <ts/ts.h>

.. function:: TSReturnCode TSHttpTxnClientStreamPriorityGet(TSHttpTxn txnp, TSHttpPriority* priority)

Description
===========

Retrieve the priority information for the HTTP stream associated with the
provided transaction.  The resultant priority information is populated in the
``priority`` output variable. The ``TSHttpPriority`` type is designed to be
agnostic of the various HTTP protocol versions that support HTTP streams. The
user should pass a pointer casted to ``TSHttpPriority`` from a previously
allocated ``TSHttp2Priority`` structure. This design anticipates future support
for HTTP versions that support streams, such as HTTP/3.

The ``TSHttp2Priority`` structure has the following declaration:

.. code-block:: cpp

  typedef struct {
    uint8_t priority_type; /** HTTP_PROTOCOL_TYPE_HTTP_2 */
    int32_t stream_dependency;
    uint8_t weight;
  } TSHttp2Priority;

In a call to ``TSHttpTxnClientStreamPriorityGet``, the dependency and weight
will be populated in the ``stream_dependency`` and ``weight`` members,
respectively.  If the stream associated with the given transaction has no
dependency, then the ``stream_dependency`` output parameter will be populated
with ``-1`` and the value of ``weight`` will be meaningless. See RFC 7540
section 5.3 for details concerning HTTP/2 stream priority.

This API returns an error if the provided transaction is not an HTTP/2
transaction.

See Also
========

:doc:`TSHttpTxnClientStreamIdGet.en`
