arindamkeswani/studybud

Codebase and personal notes for Dennis Ivy's 7-hour Django course

Commands used (Powershell)

• python --version
• pip install virtualenv
• Set-ExecutionPolicy Unrestricted -Force
• virtualenv env
• env\scripts\activate
• pip install django
• django-admin
• django-admin startproject studybud
• cd studybud
• python manage.py runserver
• python manage.py startapp base
• python manage.py migrate (running server would not give unapplied migrations error anymore)
• python manage.py makemigrations (followed by python manage.py migrate)
• python manage.py createsuperuser

Notes

(In studybud/settings.py) adding 'base.apps.BaseConfig' will connect the project folder to the new app that we just added (inside base folder)

Two URLs have been used in this project (route URLs file, and one for our specific app)

path('', home) has the specfied path as the first parameter, and the associated logic in the form of a function as the second parameter

The views (which represent the business logic in Django) should preferably not be defined in urls.py of the main project. Instead, write the views in the base app by creating a urls.py in the base folder

The urls.py file inside studybud folder is used for the entire project, but other files, such as the one in base folder is for a specific app

Paths are stored in a list, which has been done in urlpatterns=[]

URLs can be accessed by their name, which can be defined in the path itself

URLs from other apps can be used with the help of include, e.g. path('', include('base.urls'))

Use template inheritance to include pieces of code in other pages, e.g. a Navbar is typically rendered as a part of all pages, so instead of re-writing the code for it, we can simply inherit it

Django templating is similar to Jinja2, which is used for templating in Flask

One can create app-specific templates (i.e. templates that are not needed throughout the project) by creating a templates folder inside the app, followed by another folder inside this templates folder, which has the same name as the app name

Instead of specifying a path inside href, we can use names (that have been specified in urls) for links using url tag. Sample syntax: <a href="{% url 'room' room.id %}">{{room.name}}</a>

Database & Admin Panel

We have some apps made by Django by default, which have databases of their own. They can be viewed in settings.py (INSTALLED_APPS list). So we have some tables prepared by Django that are ready to be migrated

Django Admin Panel lets us view our database, as well as perform CRUD operations on the tables

In the python class used for creating DB, the null parameter is False by default. Setting it to True would mean that that particular instance of the model can have the target field as blank. blank parameter is used for forms, for options similar to required fields

auto_now=True means that we want to note down the time at an instance of a model of the database was last updated. This is built-in in Django

auto_now_add=True notes down the timestamp of data creation

on_delete=models.CASCADE on a foreign key will delete the element if its parent is deleted. If a room is deleted, the messages of that room will also be deleted

admin.site.register(ModelName) will register the model so that it can be viewed in the admin panel

CRUD

If we do not specify action inside a form, it will send the data to the current URL

{{form.as_p}} wraps the form data in the paragraph tag

To pre-fill a form, you may follow this syntax: form = SomeForm(instance=some_data)

Setting href="{{request.META.HTTP_REFERER}}" inside a link in your template will send the user back to where they came from

Search

To pass query parameters inside the anchor tag, you may use the following syntax: <a href="{% url 'some_page' %}?q={{parameter_to_be_passed}}">{{display_text}}</a>

filter() method returns all the results if no parameter is passed to it

To refer to a schema using a foreign key (i.e. a parent schema), use double-underscore, e.g. rooms = Room.objects.filter(topic__name=q)

Restricted Pages

The login_required decorator acts like a middleware function that prevents a user from visiting certain pages without logging in. Syntax: @login_required(login_required='/login')

request.user.is_authenticated checks whether a user is logged in or not

User registration

commit=False enables us to acces the form data without saving it into the database