Returns a specific HTTP request value.
The value associated with the specific GetHTTPxxxx attribute.
This is normally set within the SetOECGIRequest service. These are parsed from the HTTP request array that is passed in from the OECGI. This service is not called directly as other services normally are. It is a generic service that various 'GetHTTPxxxx' services will call. This is why the meta data doesn't include GetHTTPValue but one or more specific GetHTTPxxxx options which are listed in the Syntax block above.