babu-thomas/django-tutorial

Learning Django, a Python web framework

Django Tutorial

Learning Django, a Python web framework.

Useful commands

• Install: pip install Django
• Generate project: django-admin startproject <project_name> .
  • Notice the .(period) at the end. This will generate the project in the current directory.
  • A project generated in the root repo is necessary to deploy on Heroku.
• Run server: python manage.py runserver
• Generate new app: python manage.py startapp <app_name>
• Run database migrations: python manage.py migrate
  • This command creates the necessary database tables needed by the apps listed in INSTALLED_APPS setting in settings.py.
  • Synchronizes the models with the database schema.
• Save the changes to the model of <app_name> as a migration: python manage.py makemigrations <app_name>
  • This will create a python file named something like <app_name>/migrations/0001_initial.py which will contain the python code for the migrations.
• See the raw SQL commands that will be run on applying a migration: python manage.py sqlmigrate <app_name> 0001
  • This command doesn't actually run the migration. It just outputs what SQL commands will be run on migration.
• Create an admin user who can login to the admin site: python manage.py createsuperuser
• Run tests: python manage.py test
  • Output verbosity can be set by verbosity argument. For example, --verbosity=2

Migration Process

1. Change or create models in models.py
2. Create migrations for the changes: python manage.py makemigrations
3. Apply migrations to the database: python manage.py migrate

Sending password reset email

• For debugging, the console email backend can be used. This will just print the email to the console.
• To use the console email client add the following line to settings.py:

EMAIL_BACKEND = 'django.core.mail.backends.console.EmailBackend'

• To actually send emails to users, a service like Sendgrid can be used.
• Follow the below steps to configure Sendgrid:
  1. Create free account on Sendgrid
  2. Once logged in, choose SMTP Relay option of sending mail, then create an API Key.
  3. Make note of the username and password given.
  4. Add the username and password to environment variables:
     • On Windows:

     set SENDGRID_USERNAME=<your_username>
     set SENDGRID_PASSWORD=<your_password>
     

     • On Heroku:

     heroku config:set SENDGRID_USERNAME=<your_username>
     heroku config:set SENDGRID_PASSWORD=<your_password>
     

  5. In the Django application, add the following lines to settings.py:

   EMAIL_BACKEND = 'django.core.mail.backends.smtp.EmailBackend'
   EMAIL_HOST = 'smtp.sendgrid.net'
   EMAIL_HOST_USER = os.environ.get('SENDGRID_USERNAME')
   EMAIL_HOST_PASSWORD = os.environ.get('SENDGRID_PASSWORD')
   EMAIL_PORT = 587
   EMAIL_USE_TLS = True
  

Deploy to Heroku

1. Make an account on Heroku and install their CLI

2. Install gunicorn server: pipenv install gunicorn

3. Set ALLOWED_HOSTS in settings.py to ['*']

4. Ensure Pipfile.lock is present in repo root

5. Create Procfile in repo root

   • Example here

6. Login to Heroku account from command line: heroku login

7. Create new app on Heroku: heroku create

   • Optionally rename app: heroku apps:rename <newname>

8. Add hook for Heroku within git: heroku git:remote -a <app_name>

9. Configure static files

   • Either ignore static files or serve them using WhiteNoise
   • Ignore: heroku config:set DISABLE_COLLECTSTATIC=1
   • Use WhiteNoise
     • Install: pipenv install whitenoise
     • Add whitenoise to INSTALLED_APPS in settings.py above the built-in staticfiles app

      INSTALLED_APPS = [
      ...
      'whitenoise.runserver_nostatic', # here
      'django.contrib.staticfiles',
      ...
      ]
     

     • Add whitenoise to MIDDLEWARE in settings.py after SecurityMiddleware and SessionMiddleware

      MIDDLEWARE = [
      'django.middleware.security.SecurityMiddleware',
      'django.contrib.sessions.middleware.SessionMiddleware',
      'whitenoise.middleware.WhiteNoiseMiddleware', # here
      ...
     

     • Add STATIC_ROOT and STATICFILES_STORAGE setting in settings.py

      STATIC_ROOT = os.path.join(BASE_DIR, 'staticfiles')
      STATICFILES_STORAGE = 'whitenoise.storage.CompressedManifestStaticFilesStorage'
     

10. Push code to Heroku: git push heroku master

11. Make app live: heroku ps:scale web=1

12. Open app in browser: heroku open