$Web Response

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: 0 Response header parameter set. -1 Not a web thread -5 Parameter name missing.
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/.