doc/sdk/http-headers/guide-to-trafficserver-http-header-system.en.rst

Guide to Traffic Server HTTP Header System

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No Null-Terminated Strings
~~~~~~~~~~~~~~~~~~~~~~~~~~

It's not safe to assume that string data contained in marshal buffers
(such as URLs and MIME fields) is stored in null-terminated string
copies. Therefore, your plugins should always use the length parameter
when retrieving or manipulating these strings. You **cannot** pass in
``NULL`` for string-length return values; string values returned from
marshall buffers are not null-terminated. If you need a null-terminated
value, then use ``TSstrndup`` to automatically null-terminate a string.
The strings that come back and are not null-terminated **cannot** be
passed into the common ``str*()`` routines

.. note::
   Values returned from a marshall buffer can be ``NULL``, which means the
   field or object requested does not exist.

For example (from the ``blacklist-1`` sample)

.. code-block:: c

   char *host_string;
   int host_length;
   host_string = TSUrlHostGet (bufp, url_loc, &host_length);
   for (i = 0; i < nsites; i++) {
   if (strncmp (host_string, sites[i], host_length) == 0) {
      // ...
   }

See the sample plugins for additional examples.

.. toctree::
   :maxdepth: 2

   guide-to-trafficserver-http-header-system/duplicate-mime-fields-are-not-coalesced.en
   guide-to-trafficserver-http-header-system/mime-fields-always-belong-to-an-associated-mime-header.en
   guide-to-trafficserver-http-header-system/release-marshal-buffer-handles.en