Please follow these coding standards when writing code for inclusion in Django.
Unless otherwise specified, follow PEP 8.
You could use a tool like pep8 to check for some problems in this area, but remember that PEP 8 is only a guide, so respect the style of the surrounding code as a primary goal.
One big exception to PEP 8 is our preference of longer line lengths. We’re well into the 21st Century, and we have high-resolution computer screens that can fit way more than 79 characters on a screen. Don’t limit lines of code to 79 characters if it means the code looks significantly uglier or is harder to read.
Use four spaces for indentation.
Use underscores, not camelCase, for variable, function and method names (i.e. poll.get_unique_voters(), not poll.getUniqueVoters).
Use InitialCaps for class names (or for factory functions that return classes).
In docstrings, use “action words” such as:
def foo():
"""
Calculates something and returns the result.
"""
pass
Here’s an example of what not to do:
def foo():
"""
Calculate something and return the result.
"""
pass
In Django template code, put one (and only one) space between the curly brackets and the tag contents.
Do this:
{{ foo }}
Don’t do this:
{{foo}}
In Django views, the first parameter in a view function should be called request.
Do this:
def my_view(request, foo):
# ...
Don’t do this:
def my_view(req, foo):
# ...
Field names should be all lowercase, using underscores instead of camelCase.
Do this:
class Person(models.Model):
first_name = models.CharField(max_length=20)
last_name = models.CharField(max_length=40)
Don’t do this:
class Person(models.Model):
FirstName = models.CharField(max_length=20)
Last_Name = models.CharField(max_length=40)
The class Meta should appear after the fields are defined, with a single blank line separating the fields and the class definition.
Do this:
class Person(models.Model):
first_name = models.CharField(max_length=20)
last_name = models.CharField(max_length=40)
class Meta:
verbose_name_plural = 'people'
Don’t do this:
class Person(models.Model):
first_name = models.CharField(max_length=20)
last_name = models.CharField(max_length=40)
class Meta:
verbose_name_plural = 'people'
Don’t do this, either:
class Person(models.Model):
class Meta:
verbose_name_plural = 'people'
first_name = models.CharField(max_length=20)
last_name = models.CharField(max_length=40)
The order of model inner classes and standard methods should be as follows (noting that these are not all required):
If choices is defined for a given model field, define the choices as a tuple of tuples, with an all-uppercase name, either near the top of the model module or just above the model class. Example:
DIRECTION_CHOICES = (
('U', 'Up'),
('D', 'Down'),
)
Modules should not in general use settings stored in django.conf.settings at the top level (i.e. evaluated when the module is imported). The explanation for this is as follows:
Manual configuration of settings (i.e. not relying on the DJANGO_SETTINGS_MODULE environment variable) is allowed and possible as follows:
from django.conf import settings
settings.configure({}, SOME_SETTING='foo')
However, if any setting is accessed before the settings.configure line, this will not work. (Internally, settings is a LazyObject which configures itself automatically when the settings are accessed if it has not already been configured).
So, if there is a module containing some code as follows:
from django.conf import settings
from django.core.urlresolvers import get_callable
default_foo_view = get_callable(settings.FOO_VIEW)
...then importing this module will cause the settings object to be configured. That means that the ability for third parties to import the module at the top level is incompatible with the ability to configure the settings object manually, or makes it very difficult in some circumstances.
Instead of the above code, a level of laziness or indirection must be used, such as django.utils.functional.LazyObject, django.utils.functional.lazy() or lambda.
Dec 23, 2012