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Development Notes
This page is a work in progress: I started it to put my personal notes while I go through the source code. Feel free to add/amend/delete as needed. Disclaimer: I'm new to Django so information here can be wrong. If anyone can contrast this information, please feel free to delete this disclaimer!
Lernanta is the code that makes P2PU run. It is based on the Python web development framework Django.
This is an open source project and as such it welcomes contributions from the community. To get started you will ned to download the source code. Instructions can be found in the Development Documentation section of this wiki. You can also follow the fantastic course Introduction to Lernanta from the P2PU site.
As it is common in Django projects, Lernanta is divided into several applications and it also re-uses third party ones.
Code for the different applications in Lernanta can be found in the module structure lernanta.apps.application-name, where application-name is one of the specific applications created for the system (for instance badges, dashboard, or schools). The templates for those applications can be found in lernanta/templates/application-name.
Inside each of the applications the following files can be found (Note that not all applications need all these files):
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models.py : contains the models to be persisted to the database
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views.py : contains code that is generally consider as controller code in other frameworks
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urls.py : contains the routes that map actions in the views
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admin.py : contains code for the admin site for the particular application
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decorators.py : contains decorators that can be used in the views (an also in templates??? CHECK)
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forms.py : contains code to use in forms in the templates section
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tests.py : contains tests for the app
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tasks.py : ???
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utils.py : ???
Most classes inherit from ModelBase in the Drumbeat application. From this they inherit models.Model so that they can be persisted to the DB through Django's own ORM.
A Project can be a Course, a Study Group, or a Challenge. This property is stored in the category field of the Project model.
All types of content have been abstracted as Page models in the content app. It seems to model Tasks and other functionality in the form of an abstract page (to be presented to the user).
As far as I can see the default Django templates are used. Although Jinja2 is installed as a development dependency to use test_utils.
Querying objects in Django is done through the object's Manager. At least one Manager exists, objects, which is only accessible through the model class (not from instances). Some models in Lernanta provide their own custom Manager i.e. ProjectManager, which provides custom methods to access popular and active projects. The manager can be override in the model with the following code:
objects = ProjectManager()
Please have a look at How to test Django applications if you are unfamiliar with the topic.
Lernanta uses nose which is a extension on unittest to make testing easier. The particular package django-nose is used in here.
As far as I can see django-nose and test_utils both are tests runners (although the latter does a bunch of stuff more). TODO: check with Zuzel if both are being used. This particular test_utils skips database creation if the db already exists so integration tests for models run faster. It can also provide mock Request objects to isolate your tests to a degree. Not sure why test_util.TestCase is used though, cause seems to be the same as django.test.TestCase but injecting Jinja, and I don't think Jinja is used at all... check this one too!
Lernata uses memcached as a caching solution, as can be seen in the configuration file for non local environments. TODO: check this cause I cannot see any memcache calls in the code (although as noted below, there is some Django caching going on).
Locally, for development purposes, it defaults to the dummy cache provided by Django.
TODO: there are some caching arguments passed into drumbeat main ModelBase (import caching.base); find out what is that about... More information on Django caching
Some examples of caching in the Project model. See both cache.get(...) and cache.set(...) actions there.
Lernanta development moves fast so to keep up to date you have to pull changes from the main repository (generally called upstream if you have followed github documentation on forking repos) quite often. After a pull, you will need to run any migrations generated by changes to the model classes. To do so you can just type in your console:
./manage.py migrate
More information on generating and running migrations with South in the docs.
From time to time some of the packages that Lernanta depends on will also change, for instance, to upgrade Django to a new release. In that case the contents of the requirements folder will change and you can use the following command to install the new dependencies (note that installing dev.txt will pull in the dependencies in prod.txt):
pip install -r requirements/dev.txt
That command should work assuming that you are using virtualenv, otherwise you might need sudo to install some of the packages needed.
List of django apps that lernanta re-uses:
django-taggit is used to make tagging easier. You can see an example in the Projects model tag attribute.
South to handle migrations.
Nose as a test runner for programmer's testing.
distribute as a replacement for setuptools.
Celery as a distribute Tasks queue.
Beautiful Soup for screen scrapping.