Description
The standard (http://www.imsglobal.org/LTI/v1p1p1/ltiIMGv1p1p1.html#_Toc330273035) specifies a few other types of interaction besides just posting the grade.
6.1.2 "readResult" for getting the grade from the LTI Consumer, for instance.
generating the message can be done with generate_request_xml setting operation to "readResult" but posting it with post_message will just yield "success" but not the actual grade
Currently, this can be worked around by calling the internal _post_patched_request directly but I feel this is more than somewhat hackish.
Would be happy to implement a fix to this if you explain how you want it in terms of architecture. My proposal would be to have post_message return either False when request fails but the response xml when it is successful, but there are quite a few other ways this issue could be approached.