.. _-optionalHeaderValuePF-:

optionalHeaderValuePF
=====================

Signature
---------

.. includecode2:: /../../akka-http/src/main/scala/akka/http/scaladsl/server/directives/HeaderDirectives.scala
   :snippet: optionalHeaderValuePF

Description
-----------
Calls the specified partial function with the first request header the function is ``isDefinedAt`` and extracts the
result of calling the function.

The ``optionalHeaderValuePF`` directive is similar to the :ref:`-headerValuePF-` directive but always extracts an ``Option``
value instead of rejecting the request if no matching header could be found.

Example
-------

.. includecode2:: ../../../../code/docs/http/scaladsl/server/directives/HeaderDirectivesExamplesSpec.scala
   :snippet: optionalHeaderValuePF-0