Forked from - Wed Jun 21 09:01:59 EDT 2017 https://github.com/tophatmonocle/ims_lti_py

Interestingly, the code in Pypi fails: https://pypi.python.org/pypi/ims_lti_py/0.5

And the code in the Harvard fork fails: https://github.com/harvard-dce/dce_lti_py

But the trunk of this works https://github.com/tophatmonocle/ims_lti_py

 
from lxml import etree, objectify
import six

CODE_MAJOR_CODES = ["success", "processing", "failure", "unsupported"]

SEVERITY_CODES = ["status", "warning", "error"]

accessors = [
    "request_type",
    "score",
    "message_identifier",
    "response_code",
    "post_response",
    "code_major",
    "severity",
    "description",
    "operation",
    "message_ref_identifier",
]


class OutcomeResponse:

This class consumes & generates LTI Outcome Responses.

Response documentation:

http://www.imsglobal.org/LTI/v1p1/ltiIMGv1p1.html#_Toc319560472

Error code documentation:

http://www.imsglobal.org/gws/gwsv1p0/imsgws_baseProfv1p0.html#1639667

This class can be used by both Tool Providers and Tool Consumers, though each will use it differently. TPs will use it to partse the result of an OutcomeRequest to the TC. A TC will use it to generate proper response XML to send back to a TP.

 
    def __init__(self, **kwargs):

Initialize all class accessors to None

        for opt in accessors:
            setattr(self, opt, None)
 

Store specified options in our options member

        for (key, val) in six.iteritems(kwargs):
            setattr(self, key, val)

    @staticmethod
    def from_post_response(post_response, content):

Convenience method for creating a new OutcomeResponse from a response object.

        response = OutcomeResponse()
        response.post_response = post_response
        response.response_code = post_response.status
        response.process_xml(content)
        return response

    def is_success(self):
        return self.code_major == "success"

    def is_processing(self):
        return self.code_major == "processing"

    def is_failure(self):
        return self.code_major == "failure"

    def is_unsupported(self):
        return self.code_major == "unsupported"

    def has_warning(self):
        return self.severity == "warning"

    def has_error(self):
        return self.severity == "error"

    def process_xml(self, xml):

Parse OutcomeResponse data form XML.

        try:
            root = objectify.fromstring(xml)

Get message idenifier from header info

            self.message_identifier = (
                root.imsx_POXHeader.imsx_POXResponseHeaderInfo.imsx_messageIdentifier
            )

            status_node = root.imsx_POXHeader.imsx_POXResponseHeaderInfo.imsx_statusInfo
 

Get status parameters from header info status

            self.code_major = status_node.imsx_codeMajor
            self.severity = status_node.imsx_severity
            self.description = status_node.imsx_description
            self.message_ref_identifier = str(status_node.imsx_messageRefIdentifier)
            self.operation = status_node.imsx_operationRefIdentifier

            try:

Try to get the score

                self.score = str(
                    root.imsx_POXBody.readResultResponse.result.resultScore.textString
                )
            except AttributeError:

Not a readResult, just ignore!

                pass
        except:
            pass

    def generate_response_xml(self):

Generate XML based on the current configuration.

        root = etree.Element(
            "imsx_POXEnvelopeResponse",
            xmlns="http://www.imsglobal.org/services/ltiv1p1/xsd/imsoms_v1p0",
        )

        header = etree.SubElement(root, "imsx_POXHeader")
        header_info = etree.SubElement(header, "imsx_POXResponseHeaderInfo")
        version = etree.SubElement(header_info, "imsx_version")
        version.text = "V1.0"
        message_identifier = etree.SubElement(header_info, "imsx_messageIdentifier")
        message_identifier.text = str(self.message_identifier)
        status_info = etree.SubElement(header_info, "imsx_statusInfo")
        code_major = etree.SubElement(status_info, "imsx_codeMajor")
        code_major.text = str(self.code_major)
        severity = etree.SubElement(status_info, "imsx_severity")
        severity.text = str(self.severity)
        description = etree.SubElement(status_info, "imsx_description")
        description.text = str(self.description)
        message_ref_identifier = etree.SubElement(
            status_info, "imsx_messageRefIdentifier"
        )
        message_ref_identifier.text = str(self.message_ref_identifier)
        operation_ref_identifier = etree.SubElement(
            status_info, "imsx_operationRefIdentifier"
        )
        operation_ref_identifier.text = str(self.operation)

        body = etree.SubElement(root, "imsx_POXBody")
        response = etree.SubElement(body, "%s%s" % (self.operation, "Response"))

        if self.score:
            result = etree.SubElement(response, "result")
            result_score = etree.SubElement(result, "resultScore")
            language = etree.SubElement(result_score, "language")
            language.text = "en"
            text_string = etree.SubElement(result_score, "textString")
            text_string.text = str(self.score)

        return '<?xml version="1.0" encoding="UTF-8"?>' + etree.tostring(root)