django1/django/apps/base.py

107 lines
4.1 KiB
Python

from importlib import import_module
from django.core.exceptions import ImproperlyConfigured
from django.utils.module_loading import import_by_path, module_has_submodule
from django.utils._os import upath
MODELS_MODULE_NAME = 'models'
class AppConfig(object):
"""
Class representing a Django application and its configuration.
"""
def __init__(self, app_name):
# Full Python path to the application eg. 'django.contrib.admin'.
self.name = app_name
# Root module for the application eg. <module 'django.contrib.admin'
# from 'django/contrib/admin/__init__.pyc'>.
self.app_module = import_module(app_name)
# The following attributes could be defined at the class level in a
# subclass, hence the test-and-set pattern.
# Last component of the Python path to the application eg. 'admin'.
# This value must be unique across a Django project.
if not hasattr(self, 'label'):
self.label = app_name.rpartition(".")[2]
# Human-readable name for the application eg. "Admin".
if not hasattr(self, 'verbose_name'):
self.verbose_name = self.label.title()
# Filesystem path to the application directory eg.
# u'/usr/lib/python2.7/dist-packages/django/contrib/admin'. May be
# None if the application isn't a bona fide package eg. if it's an
# egg. Otherwise it's a unicode on Python 2 and a str on Python 3.
if not hasattr(self, 'path'):
try:
self.path = upath(self.app_module.__path__[0])
except AttributeError:
self.path = None
# Module containing models eg. <module 'django.contrib.admin.models'
# from 'django/contrib/admin/models.pyc'>. Set by import_models().
# None if the application doesn't have a models module.
self.models_module = None
# Mapping of lower case model names to model classes. Initally set to
# None to prevent accidental access before import_models() runs.
self.models = None
def __repr__(self):
return '<AppConfig: %s>' % self.label
@classmethod
def create(cls, entry):
"""
Factory that creates an app config from an entry in INSTALLED_APPS.
"""
try:
# If import_module succeeds, entry is a path to an app module.
# Otherwise, entry is a path to an app config class or an error.
import_module(entry)
except ImportError:
# Raise the original exception when entry cannot be a path to an
# app config class. Since module names are allowable here, the
# standard exception message from import_by_path is unsuitable.
if '.' not in entry:
raise
cls = import_by_path(entry)
# Check for obvious errors. (This check prevents duck typing, but
# it could be removed if it became a problem in practice.)
if not issubclass(cls, AppConfig):
raise ImproperlyConfigured(
"%r isn't a subclass of AppConfig." % entry)
# Obtain app name here rather than in AppClass.__init__ to keep
# all error checking for entries in INSTALLED_APPS in one place.
try:
app_name = cls.name
except AttributeError:
raise ImproperlyConfigured(
"%r must supply a name attribute." % entry)
# Entry is a path to an app config class.
return cls(app_name)
else:
# Entry is a path to an app module.
return cls(entry)
def import_models(self, all_models):
# Dictionary of models for this app, stored in the 'all_models'
# attribute of the Apps this AppConfig is attached to. Injected as a
# parameter because it may get populated before this method has run.
self.models = all_models
if module_has_submodule(self.app_module, MODELS_MODULE_NAME):
models_module_name = '%s.%s' % (self.name, MODELS_MODULE_NAME)
self.models_module = import_module(models_module_name)