lti: Learning Tools Interoperability

lti is a Python library implementing the Learning Tools Interperability (LTI) standard. It is based on dce_lti_py, which is based on ims_lti_py.

Installation

pip install lti

Dependencies

• lxml
• oauthlib
• requests-oauthlib

Usage

The primary goal of this library is to provide classes for building Python LTI tool providers (LTI apps). To that end, the functionality that you're looking for is probably in the ToolConfig and ToolProvider classes (ToolConsumer is available too, if you want to consume LTI Providers).

Tool Config Example (Django)

Here's an example of a Django view you might use as the configuration URL when registering your app with the LTI consumer.

from lti import ToolConfig
from django.http import HttpResponse


def tool_config(request):

    # basic stuff
    app_title = 'My App'
    app_description = 'An example LTI App'
    launch_view_name = 'lti_launch'
    launch_url = request.build_absolute_uri(reverse('lti_launch'))

    # maybe you've got some extensions
    extensions = {
        'my_extensions_provider': {
            # extension settings...
        }
    }

    lti_tool_config = ToolConfig(
        title=app_title,
        launch_url=launch_url,
        secure_launch_url=launch_url,
        extensions=extensions,
        description = app_description
    )

    # or you may need some additional LTI parameters
    lti_tool_config.cartridge_bundle = 'BLTI001_Bundle'
    lti_tool_config.cartridge_icon = 'BLTI001_Icon'
    lti_tool_config.icon = 'http://www.example.com/icon.png'

    return HttpResponse(lti_tool_config.to_xml(), content_type='text/xml')

Tool Provider OAuth Request Validation Example (Django)

from lti.contrib.django import DjangoToolProvider
from my_app import RequestValidator


# create the tool provider instance
tool_provider = DjangoToolProvider.from_django_request(request=request)

# the tool provider uses the 'oauthlib' library which requires an instance
# of a validator class when doing the oauth request signature checking.
# see https://oauthlib.readthedocs.org/en/latest/oauth1/validator.html for
# info on how to create one
validator = RequestValidator()

# validate the oauth request signature
ok = tool_provider.is_valid_request(validator)

# do stuff if ok / not ok

Tool Consumer Example (Django)

In your view:

def index(request):
    consumer = ToolConsumer(
        consumer_key='my_key_given_from_provider',
        consumer_secret='super_secret',
        launch_url='provider_url',
        params={
            'lti_message_type': 'basic-lti-launch-request'
        }
    )

    return render(
        request,
        'lti_consumer/index.html',
        {
            'launch_data': consumer.generate_launch_data(),
            'launch_url': consumer.launch_url
        }
    )

At the template:

<form action="{{ launch_url }}"
      name="ltiLaunchForm"
      id="ltiLaunchForm"
      method="POST"
      encType="application/x-www-form-urlencoded">
  {% for key, value in launch_data.items %}
    <input type="hidden" name="{{ key }}" value="{{ value }}"/>
  {% endfor %}
  <button type="submit">Launch the tool</button>
</form>

Testing

Unit tests can be run by executing

tox

This uses tox to set up and run the test environment.