###################
LTI Consumer XBlock
###################

Purpose
*******

This XBlock implements the consumer side of the LTI specification enabling
integration of third-party LTI provider tools.

Getting Started
***************

Installation
============

For details regarding how to deploy this or any other XBlock in the lms instance, see the `installing-the-xblock`_ documentation.

.. _installing-the-xblock: https://edx.readthedocs.io/projects/xblock-tutorial/en/latest/edx_platform/devstack.html#installing-the-xblock

Installing in Docker Devstack
-----------------------------

Assuming that your ``devstack`` repo lives at ``~/code/devstack``
and that ``edx-platform`` lives right alongside that directory, you'll want
to checkout ``xblock-lti-consumer`` and have it live in ``~/code/src/xblock-lti-consumer``.
This will make it so that you can access it inside an LMS container shell
and easily make modifications for local testing.

**You will have to run the below instructions twice, once for the LMS and once for Studio.
Otherwise you will be using different versions of the xblock in the two containers.**

Run ``make dev.shell.lms`` or ``make dev.shell.studio`` from your ``devstack`` directory to enter a running container.
Once in there, you can do the following to have your devstack pointing at a local development
version of ``xblock-lti-consumer``:

.. code:: bash

$ pushd /edx/src/xblock-lti-consumer
$ virtualenv venv/
$ source venv/bin/activate
$ make install
$ make test # optional, if you want to see that everything works
$ deactivate
$ pushd # should take you back to /edx/app/edxapp/edx-platform
$ pip uninstall -y lti_consumer_xblock
$ pip install -e /edx/src/xblock-lti-consumer

Enabling in Studio
------------------

You can enable the LTI Consumer XBlock in Studio through the
advanced settings.

1. From the main page of a specific course, navigate to
``Settings -> Advanced Settings`` from the top menu.
2. Check for the ``advanced_modules`` policy key, and add
``"lti_consumer"`` to the policy value list.
3. Click the "Save changes" button.

Developing
===========

One Time Setup
--------------
.. code:: bash

# Clone the repository
git clone git@github.com:openedx/xblock-lti-consumer.git
cd xblock-lti-consumer

# Set up a virtualenv using virtualenvwrapper with the same name as the repo and activate it
mkvirtualenv -p python3.8 xblock-lti-consumer

Every time you develop something in this repo
---------------------------------------------
.. code:: bash

# Activate the virtualenv
workon xblock-lti-consumer

# Grab the latest code
git checkout master
git pull

# Install/update the dev requirements
make install

# Run the tests (to verify the status before you make any changes)
make test

# Make a new branch for your changes
git checkout -b <your_github_username>/<short_description>

# Using your favorite editor, edit the code to make your change.
vim ...

# Changes to style rules should be made to the Sass files, compiled to CSS,
# and committed to the git repository.
make compile-sass

# Run your new tests
pytest ./path/to/new/tests

# Run quality checks
make quality

# Add a changelog entry to CHANGELOG.rst

# Commit all your changes
git commit ...
git push

# Open a PR and ask for review.

Package Requirements
--------------------

setup.py contains a list of package dependencies which are required for this XBlock package.
This list is what is used to resolve dependencies when an upstream project is consuming
this XBlock package. requirements.txt is used to install the same dependencies when running
the tests for this package.

Downloading translations from Transifex
---------------------------------------

If you want to download translations from Transifex install
`transifex client <https://docs.transifex.com/client/installing-the-client/>`_ and run this command while
inside project root directory:

.. code:: bash

$ tx pull -f --mode=reviewed -l en,ar,es_419,fr,he,hi,ko_KR,pt_BR,ru,zh_CN

Further Development Info
------------------------

See the `developer guide`_ for implementation details and other developer concerns.

.. _developer guide: ./docs/developing.rst

Testing
*******

Testing Against an LTI Provider
===============================

LTI 1.1
-------

http://lti.tools/saltire/ provides a "Test Tool Provider" service that allows
you to see messages sent by an LTI consumer.

We have some useful documentation on how to set this up here:
http://edx.readthedocs.io/projects/open-edx-building-and-running-a-course/en/latest/exercises_tools/lti_component.html#lti-authentication-information

1. In Studio Advanced settings, set the value of the "LTI Passports" field to "test:test:secret" -
this will set the OAuth client key and secret used to send a message to the test LTI provider.
2. Create an LTI Consumer problem in a course in Studio (after enabling it in "advanced_modules"
as seen above). Make a unit, select "Advanced", then "LTI Consumer".
3. Click edit and fill in the following fields:
``LTI ID``: "test"
``LTI URL``: "https://lti.tools/saltire/tp"
4. Click save. The unit should refresh and you should see "Passed" in the "Verification" field of
the message tab in the LTI Tool Provider emulator.
5. Click the "Publish" button.
6. View the unit in your local LMS. If you get an ``ImportError: No module named lti_consumer``, you
should ``docker-compose restart lms`` (since we previously uninstalled the lti_consumer to get the
tests for this repo running inside an LMS container). From here, you can see the contents of the
messages that we are sending as an LTI Consumer in the "Message Parameters" part of the "Message" tab.

LTI 1.3
-------

IMS Global provides a reference implementation of LTI 1.3 that can be used to test the XBlock.

On LTI 1.3 the authentication mechanism used is OAuth2 using the Client Credentials grant, this means
that to configure the tool, the LMS needs to know the keyset URL or public key of the tool, and the tool
needs to know the LMS's one.

Instructions:

1. Set up a local tunnel tunneling the LMS (using `ngrok` or a similar tool) to get a URL accessible from the internet.
2. Create a new course, and add the `lti_consumer` block to the advanced modules list.
3. In the course, create a new unit and add the LTI block.

* Set ``LTI Version`` to ``LTI 1.3``.
* Set the ``Tool Launch URL`` to ``https://lti-ri.imsglobal.org/lti/tools/``

4. In Studio, you'll see a few parameters being displayed in the preview:

.. code::

Client ID: f0532860-cb34-47a9-b16c-53deb077d4de
Deployment ID: 1
# Note that these are LMS URLS
Keyset URL: http://localhost:18000/api/lti_consumer/v1/public_keysets/block-v1:OpenCraft+LTI101+2020_T2+type@lti_consumer+block@efc55c7abb87430883433bfafb83f054
Access Token URL: http://localhost:18000/api/lti_consumer/v1/token/block-v1:OpenCraft+LTI101+2020_T2+type@lti_consumer+block@efc55c7abb87430883433bfafb83f054
OIDC Callback URL: http://localhost:18000/api/lti_consumer/v1/launch/

5. Add the tunnel URL to the each of these URLs as it'll need to be accessed by the tool (hosted externally).

.. code::

# This is <LMS_URL>/api/lti_consumer/v1/public_keysets/<BLOCK_LOCATION>
https://647dd2e1.ngrok.io/api/lti_consumer/v1/public_keysets/block-v1:OpenCraft+LTI101+2020_T2+type@lti_consumer+block@996c72b16070434098bc598bd7d6dbde

6. Set up a tool in the IMS Global reference implementation (https://lti-ri.imsglobal.org/lti/tools/).

* Click on ``Add tool`` at the top of the page (https://lti-ri.imsglobal.org/lti/tools).
* Add the parameters and URLs provided by the block, and generate a private key on https://lti-ri.imsglobal.org/keygen/index and paste it there (don't close the tab, you'll need the public key later).

7. Go back to Studio, and edit the block adding its settings (you'll find them by scrolling down https://lti-ri.imsglobal.org/lti/tools/ until you find the tool you just created):

.. code::

Tool Launch URL: https://lti-ri.imsglobal.org/lti/tools/[tool_id]/launches
Tool Initiate Login URL: https://lti-ri.imsglobal.org/lti/tools/[tool_id]/login_initiations
Tool Public key: Public key from key page.

8. Publish block, log into LMS and navigate to the LTI block page.
9. Click ``Send Request`` and verify that the LTI launch was successful.

.. admonition:: Testing using ``ngrok``

When launching LTI 1.3 requests through ``ngrok``, make sure your LMS is serving session cookies marked as
``Secure`` and with the ``SameSite`` attribute set to ``None``. You can do this by changing ``SESSION_COOKIE_SECURE: true``
and ``DCS_SESSION_COOKIE_SAMESITE: None`` in your ``lms.yml`` configuration files. Note that this will break logins
for locally accessed URLs in the devstack.

LTI Advantage Features
----------------------

This XBlock supports LTI 1.3 and the following LTI Avantage services:

* Deep Linking (LTI-DL)
* Assignments and Grades services (LTI-AGS)
* Names and Roles Provisioning services (LTI-NRP)

To enable LTI-AGS, you need to set **LTI Assignment and Grades Service** in Studio to
allow tools to send back grades. There's two grade interaction models implemented:

* **Allow tools to submit grades only (declarative)(Default)**: enables LTI-AGS and
creates a single fixed LineItem that the tools can send grades too.
* **Allow tools to manage and submit grades (programmatic)**: enables LTI-AGS and
enables full access to LTI-AGS endpoints. Tools will be able to create, manage and
delete multiple LineItems, and set multiple grades per student per problem.
*In this implementation, the tool is responsible for managing grades and linking them in the LMS.*

To enable LTI-DL and its capabilities, you need to set these settings in the block:

1. Locate the **Deep linking** setting and set it to **True (enabled)**.
2. Set **Deep Linking Launch URL** setting. You can retrieve it from the tool you’re integrating with.
If it’s not provided, try using the same value as in the LTI 1.3 Tool Launch URL.

To enable LTI-NRPS, you set **Enable LTI NRPS** to **True** in the block settings on Studio.

Getting Help
************

If you're having trouble, we have discussion forums at
https://discuss.openedx.org where you can connect with others in the
community.

Our real-time conversations are on Slack. You can request a `Slack
invitation`_, then join our `community Slack workspace`_.

For anything non-trivial, the best path is to open an issue in this
repository with as many details about the issue you are facing as you
can provide.

https://github.com/openedx/xblock-lti-consumer/issues

For more information about these options, see the `Getting Help`_ page.

.. _Slack invitation: https://openedx.org/slack
.. _community Slack workspace: https://openedx.slack.com/
.. _Getting Help: https://openedx.org/getting-help

License
*******

The code in this repository is licensed under the AGPL v3 License unless
otherwise noted.

Please see `LICENSE.txt <LICENSE.txt>`_ for details.

Contributing
************

Contributions are very welcome.
Please read `How To Contribute <https://openedx.org/r/how-to-contribute>`_ for details.

This project is currently accepting all types of contributions, bug fixes,
security fixes, maintenance work, or new features. However, please make sure
to have a discussion about your new feature idea with the maintainers prior to
beginning development to maximize the chances of your change being accepted.
You can start a conversation by creating a new issue on this repo summarizing
your idea.

The Open edX Code of Conduct
****************************

All community members are expected to follow the `Open edX Code of Conduct`_.

.. _Open edX Code of Conduct: https://openedx.org/code-of-conduct/

People
******

The assigned maintainers for this component and other project details may be
found in `Backstage`_. Backstage pulls this data from the ``catalog-info.yaml``
file in this repo.

.. _Backstage: https://backstage.openedx.org/catalog/default/component/xblock-lti-consumer

Reporting Security Issues
*************************

Please do not report security issues in public. Please email security@tcril.org.

.. |ci-badge| image:: https://github.com/openedx/xblock-lti-consumer/workflows/Python%20CI/badge.svg?branch=master
:target: https://github.com/openedx/xblock-lti-consumer/actions?query=workflow%3A%22Python+CI%22
:alt: Test suite status

.. |codecov-badge| image:: https://codecov.io/github/openedx/xblock-lti-consumer/coverage.svg?branch=master
:target: https://codecov.io/github/openedx/xblock-lti-consumer?branch=master
:alt: Code coverage

.. |status-badge| image:: https://img.shields.io/badge/Status-Maintained-brightgreen
:alt: Maintained

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:target: https://github.com/openedx/edx-rest-api-client/blob/master/LICENSE
:alt: License

.. |pypi-badge| image:: https://img.shields.io/pypi/v/lti-consumer-xblock.svg
:target: https://pypi.python.org/pypi/lti-consumer-xblock/
:alt: PyPI