====== RestRequest::getHeaderValue() ======
----

===== Definition =====

Returns the value of the given header field, transmitted with the client's request.

<code php>
String getHeaderValue ( $Key )
</code>

===== Parameters =====

   * **$Key** //String// \\ Name of the header field, which's value should be returned. The key search id done case insensitively.

===== Returns =====

  * **String** \\ Value of the element with the given key or '', if no entry with this key could be found.

===== Example =====

<code php>

$Request = new RestRequest();

// Called endpoint is: [PUT] https://www.domain.com/webservice/accounting/booking/draft
// Content is:         "id:5,account:1234,name:Mr. Smith,amount:592.30"

$Application = $Request->getApplication(); // "accounting"
$Method      = $Request->getMethod();      // "booking"

$HTTPContenttype = $Request->getHeaderValue('Content-Type');       // "application/x-www-form-urlencoded"
$HTTPLanguage    = $Request->getHeaderValue('Accepted-Language');  // "en-US"

</code>

~~NOTOC~~