def lti_launch(request, course_id, usage_id):
"""
Endpoint for all requests to embed edX content via the LTI protocol. This
endpoint will be called by a POST message that contains the parameters for
an LTI launch (we support version 1.2 of the LTI specification):
http://www.imsglobal.org/lti/ltiv1p2/ltiIMGv1p2.html
An LTI launch is successful if:
- The launch contains all the required parameters
- The launch data is correctly signed using a known client key/secret
pair
"""
if not settings.FEATURES['ENABLE_LTI_PROVIDER']:
return HttpResponseForbidden()
# Check the LTI parameters, and return 400 if any required parameters are
# missing
params = get_required_parameters(request.POST)
if not params:
return HttpResponseBadRequest()
params.update(get_optional_parameters(request.POST))
# Get the consumer information from either the instance GUID or the consumer
# key
try:
lti_consumer = LtiConsumer.get_or_supplement(
params.get('tool_consumer_instance_guid', None),
params['oauth_consumer_key']
)
except LtiConsumer.DoesNotExist:
return HttpResponseForbidden()
# Check the OAuth signature on the message
if not SignatureValidator(lti_consumer).verify(request):
return HttpResponseForbidden()
# Add the course and usage keys to the parameters array
try:
course_key, usage_key = parse_course_and_usage_keys(course_id, usage_id)
except InvalidKeyError:
log.error(
'Invalid course key %s or usage key %s from request %s',
course_id,
usage_id,
request
)
raise Http404()
params['course_key'] = course_key
params['usage_key'] = usage_key
# Create an edX account if the user identifed by the LTI launch doesn't have
# one already, and log the edX account into the platform.
authenticate_lti_user(request, params['user_id'], lti_consumer)
# Store any parameters required by the outcome service in order to report
# scores back later. We know that the consumer exists, since the record was
# used earlier to verify the oauth signature.
store_outcome_parameters(params, request.user, lti_consumer)
return render_courseware(request, params['usage_key'])
def lti_launch(request, course_id, usage_id):
"""
Endpoint for all requests to embed edX content via the LTI protocol. This
endpoint will be called by a POST message that contains the parameters for
an LTI launch (we support version 1.2 of the LTI specification):
http://www.imsglobal.org/lti/ltiv1p2/ltiIMGv1p2.html
An LTI launch is successful if:
- The launch contains all the required parameters
- The launch data is correctly signed using a known client key/secret
pair
"""
if not settings.FEATURES['ENABLE_LTI_PROVIDER']:
return HttpResponseForbidden()
# Check the LTI parameters, and return 400 if any required parameters are
# missing
params = get_required_parameters(request.POST)
if not params:
return HttpResponseBadRequest()
params.update(get_optional_parameters(request.POST))
# Get the consumer information from either the instance GUID or the consumer
# key
try:
lti_consumer = LtiConsumer.get_or_supplement(
params.get('tool_consumer_instance_guid', None),
params['oauth_consumer_key']
)
except LtiConsumer.DoesNotExist:
return HttpResponseForbidden()
# Check the OAuth signature on the message
if not SignatureValidator(lti_consumer).verify(request):
return HttpResponseForbidden()
# Add the course and usage keys to the parameters array
try:
course_key, usage_key = parse_course_and_usage_keys(course_id, usage_id)
except InvalidKeyError:
log.error(
u'Invalid course key %s or usage key %s from request %s',
course_id,
usage_id,
request
)
raise Http404()
params['course_key'] = course_key
params['usage_key'] = usage_key
# Create an edX account if the user identifed by the LTI launch doesn't have
# one already, and log the edX account into the platform.
authenticate_lti_user(request, params['user_id'], lti_consumer)
# Store any parameters required by the outcome service in order to report
# scores back later. We know that the consumer exists, since the record was
# used earlier to verify the oauth signature.
store_outcome_parameters(params, request.user, lti_consumer)
return render_courseware(request, params['usage_key'])
def lti_run(request):
"""
This method can be reached in two ways, and must always follow a POST to
lti_launch:
- The user was logged in, so this method was called by lti_launch
- The user was not logged in, so the login process redirected them back here.
In either case, the session was populated by lti_launch, so all the required
LTI parameters will be stored there. Note that the request passed here may
or may not contain the LTI parameters (depending on how the user got here),
and so we should only use LTI parameters from the session.
Users should never call this view directly; if a user attempts to call it
without having first gone through lti_launch (and had the LTI parameters
stored in the session) they will get a 403 response.
"""
# Check the parameters to make sure that the session is associated with a
# valid LTI launch
params = restore_params_from_session(request)
if not params:
# This view has been called without first setting the session
return HttpResponseForbidden()
# Remove the parameters from the session to prevent replay
del request.session[LTI_SESSION_KEY]
# Store any parameters required by the outcome service in order to report
# scores back later. We know that the consumer exists, since the record was
# used earlier to verify the oauth signature.
lti_consumer = LtiConsumer.get_or_supplement(
params.get('tool_consumer_instance_guid', None),
params['oauth_consumer_key'])
store_outcome_parameters(params, request.user, lti_consumer)
return render_courseware(request, params['usage_key'])
def lti_run(request):
"""
This method can be reached in two ways, and must always follow a POST to
lti_launch:
- The user was logged in, so this method was called by lti_launch
- The user was not logged in, so the login process redirected them back here.
In either case, the session was populated by lti_launch, so all the required
LTI parameters will be stored there. Note that the request passed here may
or may not contain the LTI parameters (depending on how the user got here),
and so we should only use LTI parameters from the session.
Users should never call this view directly; if a user attempts to call it
without having first gone through lti_launch (and had the LTI parameters
stored in the session) they will get a 403 response.
"""
# Check the parameters to make sure that the session is associated with a
# valid LTI launch
params = restore_params_from_session(request)
if not params:
# This view has been called without first setting the session
return HttpResponseForbidden()
# Remove the parameters from the session to prevent replay
del request.session[LTI_SESSION_KEY]
# Store any parameters required by the outcome service in order to report
# scores back later. We know that the consumer exists, since the record was
# used earlier to verify the oauth signature.
lti_consumer = LtiConsumer.get_or_supplement(
params.get('tool_consumer_instance_guid', None),
params['oauth_consumer_key']
)
store_outcome_parameters(params, request.user, lti_consumer)
return render_courseware(request, params['usage_key'])
def lti_launch(request, course_id, usage_id):
"""
Endpoint for all requests to embed edX content via the LTI protocol. This
endpoint will be called by a POST message that contains the parameters for
an LTI launch (we support version 1.2 of the LTI specification):
http://www.imsglobal.org/lti/ltiv1p2/ltiIMGv1p2.html
An LTI launch is successful if:
- The launch contains all the required parameters
- The launch data is correctly signed using a known client key/secret
pair
- The user is logged into the edX instance
Authentication in this view is a little tricky, since clients use a POST
with parameters to fetch it. We can't just use @login_required since in the
case where a user is not logged in it will redirect back after login using a
GET request, which would lose all of our LTI parameters.
Instead, we verify the LTI launch in this view before checking if the user
is logged in, and store the required LTI parameters in the session. Then we
do the authentication check, and if login is required we redirect back to
the lti_run view. If the user is already logged in, we just call that view
directly.
"""
if not settings.FEATURES['ENABLE_LTI_PROVIDER']:
return HttpResponseForbidden()
# Check the OAuth signature on the message
try:
if not SignatureValidator().verify(request):
return HttpResponseForbidden()
except LtiConsumer.DoesNotExist:
return HttpResponseForbidden()
params = get_required_parameters(request.POST)
if not params:
return HttpResponseBadRequest()
params.update(get_optional_parameters(request.POST))
# Store the course, and usage ID in the session to prevent privilege
# escalation if a staff member in one course tries to access material in
# another.
try:
course_key, usage_key = parse_course_and_usage_keys(course_id, usage_id)
except InvalidKeyError:
log.error(
'Invalid course key %s or usage key %s from request %s',
course_id,
usage_id,
request
)
raise Http404()
params['course_key'] = course_key
params['usage_key'] = usage_key
try:
lti_consumer = LtiConsumer.get_or_supplement(
params.get('tool_consumer_instance_guid', None),
params['oauth_consumer_key']
)
except LtiConsumer.DoesNotExist:
return HttpResponseForbidden()
# Create an edX account if the user identifed by the LTI launch doesn't have
# one already, and log the edX account into the platform.
authenticate_lti_user(request, params['user_id'], lti_consumer)
request.session[LTI_SESSION_KEY] = params
return lti_run(request)
def lti_launch(request, course_id, usage_id):
"""
Endpoint for all requests to embed edX content via the LTI protocol. This
endpoint will be called by a POST message that contains the parameters for
an LTI launch (we support version 1.2 of the LTI specification):
http://www.imsglobal.org/lti/ltiv1p2/ltiIMGv1p2.html
An LTI launch is successful if:
- The launch contains all the required parameters
- The launch data is correctly signed using a known client key/secret
pair
- The user is logged into the edX instance
Authentication in this view is a little tricky, since clients use a POST
with parameters to fetch it. We can't just use @login_required since in the
case where a user is not logged in it will redirect back after login using a
GET request, which would lose all of our LTI parameters.
Instead, we verify the LTI launch in this view before checking if the user
is logged in, and store the required LTI parameters in the session. Then we
do the authentication check, and if login is required we redirect back to
the lti_run view. If the user is already logged in, we just call that view
directly.
"""
if not settings.FEATURES['ENABLE_LTI_PROVIDER']:
return HttpResponseForbidden()
# Check the OAuth signature on the message
try:
if not SignatureValidator().verify(request):
return HttpResponseForbidden()
except LtiConsumer.DoesNotExist:
return HttpResponseForbidden()
params = get_required_parameters(request.POST)
if not params:
return HttpResponseBadRequest()
params.update(get_optional_parameters(request.POST))
# Store the course, and usage ID in the session to prevent privilege
# escalation if a staff member in one course tries to access material in
# another.
try:
course_key, usage_key = parse_course_and_usage_keys(
course_id, usage_id)
except InvalidKeyError:
log.error('Invalid course key %s or usage key %s from request %s',
course_id, usage_id, request)
raise Http404()
params['course_key'] = course_key
params['usage_key'] = usage_key
try:
lti_consumer = LtiConsumer.get_or_supplement(
params.get('tool_consumer_instance_guid', None),
params['oauth_consumer_key'])
except LtiConsumer.DoesNotExist:
return HttpResponseForbidden()
# Create an edX account if the user identifed by the LTI launch doesn't have
# one already, and log the edX account into the platform.
authenticate_lti_user(request, params['user_id'], lti_consumer)
request.session[LTI_SESSION_KEY] = params
return lti_run(request)
