$Web Response: Difference between revisions
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{{DISPLAYTITLE:$Web_Response}} | {{DISPLAYTITLE:$Web_Response}} | ||
<span class="pageSubtitle" | <span class="pageSubtitle">Set HTTP response header parameter</span> | ||
<var>$Web_Response</var> can be used to set any HTTP response header parameter. | <var>$Web_Response</var> can be used to set any HTTP response header parameter. | ||
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==Syntax== | ==Syntax== | ||
<p class="syntax" | <p class="syntax"><span class="term">%rc</span> = $Web_Response( parameter, value ) | ||
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===Syntax terms=== | ===Syntax terms=== | ||
Revision as of 18:18, 10 April 2013
Set HTTP response header parameter
$Web_Response can be used to set any HTTP response header parameter.
$Web_Response is a callable $function, and it takes two arguments and returns a numeric status code.
Syntax
%rc = $Web_Response( parameter, value )
Syntax terms
| %rc | A numeric variable to contain a return code. Possible values are:
| ||||||
|---|---|---|---|---|---|---|---|
| parameter | The name of the HTTP response header parameter. | ||||||
| value | The value of the HTTP response header parameter. |
Usage notes
Most response header parameters are set "under-the-covers" either automatically or as the result of other Janus Web Server $function calls. These automatically set parameters should be adequate for most applications. In the cases where they're not, $Web_Response provides the ability to set response header parameters directly. The response header parameter that is most likely to be useful and that can only be set with $Web_Response is the "Pragma" parameter which can be used to indicate that a response should not be cached by the browser as in the following example.
%RC = $Web_Response('Pragma', 'no-cache')
The response header parameters are not sent until the size of the response has been determined, either as the result of a $Web_Done or a $Web_ProcSend. Until one of these is issued, it is possible to change the value of a response header parameter at will.
Extreme caution should be used with this function since it provides direct access to the HTTP layer of the web protocols. $Web_Response does no validity checking for the parameter name or value specified. For more information about the HTTP protocol including a specification of all the standard response header parameters, visit http://www.ics.uci.edu/pub/ietf/http/.