Merge pull request #94 from ccnmtl/generate-xml-response-ex

generate_xml_request: add LTI launch url parameter

Author: nikolas

lti_provider/lti.py

@@ -1,9 +1,10 @@
 from django.conf import settings
+
+from lti_provider.models import LTICourseContext
 from pylti.common import (
     LTIException, LTINotInSessionException, LTI_SESSION_KEY,
     verify_request_common, LTIRoleException, LTI_ROLES, LTI_PROPERTY_LIST)
-
-from lti_provider.models import LTICourseContext
+from xml.etree import ElementTree as etree
 
 
 LTI_PROPERTY_LIST_EX = [
@@ -208,3 +209,52 @@ def user_roles(self, request):  # pylint: disable=no-self-use
 
     def sis_course_id(self, request):
         return request.session.get('lis_course_offering_sourcedid', None)
+
+    def generate_request_xml(self, message_identifier_id, operation,
+                             lis_result_sourcedid, score, launch_url):
+        # pylint: disable=too-many-locals
+        """
+        Generates LTI 1.1 XML for posting result to LTI consumer.
+
+        :param message_identifier_id:
+        :param operation:
+        :param lis_result_sourcedid:
+        :param score:
+        :return: XML string
+        """
+        root = etree.Element(u'imsx_POXEnvelopeRequest',
+                             xmlns=u'http://www.imsglobal.org/services/'
+                                   u'ltiv1p1/xsd/imsoms_v1p0')
+
+        header = etree.SubElement(root, 'imsx_POXHeader')
+        header_info = etree.SubElement(header, 'imsx_POXRequestHeaderInfo')
+        version = etree.SubElement(header_info, 'imsx_version')
+        version.text = 'V1.0'
+        message_identifier = etree.SubElement(header_info,
+                                              'imsx_messageIdentifier')
+        message_identifier.text = message_identifier_id
+        body = etree.SubElement(root, 'imsx_POXBody')
+        xml_request = etree.SubElement(
+            body, '%s%s' % (operation, 'Request'))
+        record = etree.SubElement(xml_request, 'resultRecord')
+
+        guid = etree.SubElement(record, 'sourcedGUID')
+
+        sourcedid = etree.SubElement(guid, 'sourcedId')
+        sourcedid.text = lis_result_sourcedid
+        if score is not None:
+            result = etree.SubElement(record, '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 = score.__str__()
+            if launch_url:
+                result_data = etree.SubElement(result, 'resultData')
+                lti_launch_url = etree.SubElement(
+                    result_data, 'ltiLaunchUrl')
+                lti_launch_url.text = launch_url
+        ret = "<?xml version='1.0' encoding='utf-8'?>\n{}".format(
+            etree.tostring(root, encoding='utf-8').decode('utf-8'))
+
+        return ret

lti_provider/views.py

@@ -4,19 +4,21 @@
 from django.contrib import messages
 from django.contrib.auth.decorators import login_required
 from django.contrib.auth.models import Group
-try:
-    from django.urls import reverse
-except ImportError:
-    from django.core.urlresolvers import reverse
 from django.http.response import HttpResponseRedirect
 from django.shortcuts import get_object_or_404
 from django.utils.decorators import method_decorator
 from django.views.decorators.csrf import csrf_exempt
 from django.views.generic.base import View, TemplateView
+
 from lti_provider.mixins import LTIAuthMixin
 from lti_provider.models import LTICourseContext
-from pylti.common import \
-    generate_request_xml, LTIPostMessageException, post_message
+from pylti.common import LTIPostMessageException, post_message
+
+
+try:
+    from django.urls import reverse
+except ImportError:
+    from django.core.urlresolvers import reverse
 
 
 class LTIConfigView(TemplateView):
@@ -167,9 +169,12 @@ def post(self, request, *args, **kwargs):
         except ValueError:
             score = 0
 
-        xml = generate_request_xml(
+        redirect_url = request.POST.get('next', '/')
+
+        xml = self.lti.generate_request_xml(
             self.message_identifier(), 'replaceResult',
-            self.lti.lis_result_sourcedid(request), score)
+            self.lti.lis_result_sourcedid(request), score,
+            request.build_absolute_uri(redirect_url))
 
         if not post_message(
             self.lti.consumers(), self.lti.oauth_consumer_key(request),
@@ -186,5 +191,4 @@ def post(self, request, *args, **kwargs):
             msg = ('Your score was submitted. Great job!')
             messages.add_message(request, messages.INFO, msg)
 
-            redirect_url = request.POST.get('next', '/')
             return HttpResponseRedirect(redirect_url)