Django

• Snippet - Django password hashers time comparison
• OWASP - Django Security Cheat Sheet
• Ninja
  • Fields selections Issue
• Scaffold
• Avoid overwriting Model.delete. For example, overwriting to ensure soft delete (idea from django-tenant-users):

  def delete(self, *args, hard=False, **kwargs):
  	if not hard:
  		raise DeleteError("Use Model.soft_delete()")
  	super().delete(*args, **kwargs)ht
  

• django.core.exceptions.ImproperlyConfigured: Cannot import '<app>'. Check that '<project>.<app>.apps.<App>Config.name' is correct. #troubleshooting
  • Rename <App>Config.name from <app> to <project>.<app>
• How to Switch to a Custom Django User Model Mid-Project and Document how to migrate from a built-in User model to a custom User model

Natural Key example Link to heading

+class MyModelManager(models.Manager):
+    def get_by_natural_key(self, field1, field2):
+        return self.get(field1=field1, field2=field2)
+
+
 class MyModel(models.Model):
     created_at = models.DateTimeField(auto_now_add=True)
     updated_at = models.DateTimeField(auto_now=True)
     field1 = models.CharField(max_length=254)
     field2 = models.CharField(max_length=254)
+
+    objects = MyModelManager()
+
+    def natural_key(self):
+        return (self.field1, self.field2)

Template Link to heading

Adding a char when the for loop has next element Link to heading

{% for x in tool.lists.all %}
    {{ x }}{% if not forloop.last %},{% endif %}
{% endfor %}

Testing Link to heading

Unmanaged models Link to heading

• Source

# conftest.py
def pytest_sessionstart():
    from django.apps import apps

    unmanaged_models = [m for m in apps.get_models() if not m._meta.managed]

    for m in unmanaged_models:
        m._meta.managed = True

# pyproject.toml
[tool.pytest.ini_options]
addopts = "--no-migrations"

Defining a conftest shared between all apps Link to heading

The conftest.py must be in the same directory of manage.py.

TestCase vs TransactionTestCase Link to heading

TestCase Link to heading

• is faster than TransactionTestCase
• doesn’t commit the changes
• runs each test inside a transaction to provide isolation
• wraps the tests within two nested atomic(): 1. whole class; 2. each test.
• doesn’t truncate tables after a test. Instead, it encloses the test code in a database transaction that is rolled back at the end of the test

References: Writing and running tests | Django documentation, TestCase | Django documentation, TestCase | django/django/test/testcases.py, pytest.mark.django_db | pytest-django/pytest_django/fixtures.py

TransactionTestCase Link to heading

• resets the database after the test runs by truncating all tables
• may call commit and rollback

References: TransactionTestCase | Django documentation, TransactionTestCase | django/django/test/testcases.py, pytest.mark.django_db | pytest-django/pytest_django/fixtures.py

virtual_only fields Link to heading

• Advantages: 1. Improved performance; 2. Consistent interface; 3. Compatibility with Django’s ORM; 4. Integration with serialization.
• from https://henriquebastos.net/how-chatgpt-quickly-helped-me-understand-djangos-source-code

Toolbox Link to heading

Moved to My Toolbox:

• Django - Admin
• Django - Auth
• Django - GraphQL
• Django - Healthcheck
• Django - Servers
• Django - Saving Trees

Multi-tenancy Link to heading

• django-tenants - GitHub
  • separation: multi-schema
  • identifier: subdomain and path-based
  • Examples of projects using it: bakeup, Zango, authentik, koku
  • django-tenant-users - GitHub
    • Examples: RPGnotes
• django-multitenant
  • separation: row-based
  • identifier: out of scope
  • depends on PostgreSQL + Citus