Handles HTTP GET requests for resources of type ScriptGeneratedResource.
The generated resource is either a GraphNode or a response with
the media type specified by the producedType property
of the associated script.
GraphNodes can be rendered by Renderlets registered for the type
of the GraphNode.
UriInfo, Request, and HttpHeaders are provided
to the generating script for use in execution. In a script, they are
accessible under the names: uriInfo, request, and httpHeaders respectively.
uriInfo - info about the request URI.
request - helper for request processing
httpHeaders - provides access to HTTP header information
The generated resource. If no script is found, a NOT FOUND (404)
response is returned.