doc/developer-guide/plugins/http-headers/marshal-buffers.en.rst

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

.. _developer-plugins-http-headers-marshal-buffers:

Marshal Buffers
***************

A *marshal buffer*, or ``TSMBuffer``, is a heap data structure that
stores parsed URLs, MIME headers, and HTTP headers. You can allocate new
objects out of marshal buffers and change the values within a marshal
buffer. Whenever you manipulate an object, you require the handle to the
object (``TSMLoc``) and the marshal buffer containing the object
(``TSMBuffer``).

Routines exist for manipulating the object based on these two pieces of
information. For examples, see one of the following:

-  :ref:`developer-plugins-http-headers`
-  :ref:`developer-plugins-http-headers-urls`
-  :ref:`developer-plugins-http-headers-mime-headers`

The **marshal buffer functions** enable you to create and destroy
Traffic Server's marshal buffers, which are the data structures that
hold parsed URLs, MIME headers, and HTTP headers.

.. caution::
   Any marshal buffer fetched by ``TSHttpTxn*Get`` will be used by other
   parts of the system. Be careful not to destroy these shared transaction
   marshal buffers in functions such as those below:

-  `TSHttpTxnCachedReqGet <http://people.apache.org/~amc/ats/doc/html/InkAPI_8cc.html#a889b626142157077f4f3cfe479e8b8e2>`_
-  `TSHttpTxnCachedRespGet <http://people.apache.org/~amc/ats/doc/html/InkAPI_8cc.html#ae8f24b8dabb5008ad11620a11682ffd6>`_
-  `TSHttpTxnClientReqGet <http://people.apache.org/~amc/ats/doc/html/InkAPI_8cc.html#acca66f22d0f87bf8f08478ed926006a5>`_
-  `TSHttpTxnClientRespGet <http://people.apache.org/~amc/ats/doc/html/InkAPI_8cc.html#a92349c8363f72b1f6dfed3ae80901fff>`_
-  `TSHttpTxnServerReqGet <http://people.apache.org/~amc/ats/doc/html/ts_8h.html#aac2343a8b47bf9150f3ff7cd4e692d57>`_
-  `TSHttpTxnServerRespGet <http://people.apache.org/~amc/ats/doc/html/ts_8h.html#a39e8bfb199eadabb54c067ff25a9a400>`_
-  `TSHttpTxnTransformRespGet <http://people.apache.org/~amc/ats/doc/html/InkAPI_8cc.html#a20367f5469e8b7e73621c1316091d578>`_