# django-lti
A [Django reusable app](https://docs.djangoproject.com/en/4.0/intro/reusable-apps/) providing support for LTI Advantage.
## Installation
Install using pip.
```
pip install django-lti
```
## Setup
Start by adding `lti_tool` to your project's `INSTALLED_APPS`.
```python
INSTALLED_APPS = [
...
"lti_tool",
]
```
Then, add `lti_tool.middleware.LtiLaunchMiddleware` to the `MIDDLEWARE` setting.
It's important to list the `LtiLaunchMiddleware` _after_ `SessionMiddleware`.
```python
MIDDLEWARE = [
...
'django.contrib.sessions.middleware.SessionMiddleware',
'lti_tool.middleware.LtiLaunchMiddleware',
]
```
Finally, run migrations to initialize the needed database tables.
```
python manage.py migrate lti_tool
```
## Usage
### Adding JWKS and OIDC initiation URLs
To allow LTI platforms to retrieve a JWKS and initiate a launch, add paths for
`lti_tool.views.jwks` and `lti_tool.views.OIDCLoginInitView` to `urls.py`
```python
...
from lti_tool.views import jwks, OIDCLoginInitView
urlpatterns = [
path(".well-known/jwks.json", jwks, name="jwks"),
path("init/<uuid:registration_uuid>/", OIDCLoginInitView.as_view(), name="init"),
]
```
### Generating and rotating keys
Keys for the JWKS can be generated using the `rotate_keys` management command.
```
python manage.py rotate_keys
```
### Registering an LTI platform
An LTI platform can be registered through the Django admin, or using a custom
interface.
### Handling an LTI launch
To handle the LTI launch, inherit from `LtiLaunchBaseView` and implement the handler
methods for the types of LTI message types that the application supports.
```python
class ApplicationLaunchView(LtiLaunchBaseView):
def handle_resource_launch(self, request, lti_launch):
... # Required. Typically redirects the users to the appropriate page.
def handle_deep_linking_launch(self, request, lti_launch):
... # Optional.
def handle_submission_review_launch(self, request, lti_launch):
... # Optional.
def handle_data_privacy_launch(self, request, lti_launch):
... # Optional.
```
Each handler method receives the request, as well as a `LtiLaunch` object.
When a session is initiated by an LTI launch, data about the launch is available from
the request at `request.lti_launch` as an `LtiLaunch` object. During a non-LTI session
`request.lti_launch` will refer to an `AbsentLtiLaunch` object.
It is possible to distinguish between `LtiLaunch` and `AbsentLtiLaunch` objects using
the `.is_present` and `.is_absent` properties.