doc/developer-guide/api/functions/TSHttpTxnPostBufferReaderGet.en.rst

.. 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:: c

TSHttpTxnPostBufferReaderGet
****************************

Synopsis
========

.. code-block:: cpp

    #include <ts/ts.h>

.. function:: TSIOBufferReader TSHttpTxnPostBufferReaderGet(TSHttpTxn txnp)

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

Retrieve the client request body for the transaction referenced by :arg:`txnp`.
The body is read from via the returned :c:type:`TSIOBufferReader`. The returned
:c:type:`TSIOBufferReader` is owned by the caller and the caller must free it
via :c:func:`TSIOBufferReaderFree`. This function should be used in the handler
for :data:`TS_HTTP_REQUEST_BUFFER_READ_COMPLETE_HOOK`. The following example
handler makes use of :c:func:`TSHttpTxnPostBufferReaderGet`.

.. code-block:: c

   int
   CB_Read_Request_Body_Hook(TSCont contp, TSEvent event, void* data) {
     ink_assert(event == TS_EVENT_HTTP_REQUEST_BUFFER_COMPLETE);
     auto txnp = reinterpret_cast<TSHttpTxn>(data);

     TSIOBufferReader post_buffer_reader = TSHttpTxnPostBufferReaderGet(txnp);
     int64_t read_avail                  = TSIOBufferReaderAvail(post_buffer_reader);

     if (read_avail > 0) {
       char *body_bytes = reinterpret_cast<char *>(TSmalloc(sizeof(char) * read_avail));

       int64_t consumed      = 0;
       TSIOBufferBlock block = TSIOBufferReaderStart(post_buffer_reader);
       while (block != NULL) {
         int64_t data_len        = 0;
         const char *block_bytes = TSIOBufferBlockReadStart(block, post_buffer_reader, &data_len);
         memcpy(body_bytes + consumed, block_bytes, data_len);
         consumed += data_len;
         block = TSIOBufferBlockNext(block);
       }

       // Now do something with body_bytes which contains the contents of the
       // request's body.
     }

     // Remember to free the TSIOBufferReader.
     TSIOBufferReaderFree(post_buffer_reader);

     TSHttpTxnReenable(txnp);
     return 0;
   }

:ts:git:`example/plugins/c-api/request_buffer/request_buffer.c` is a simple
yet complete plugin that accesses HTTP request bodies.