447 lines
17 KiB
Python
447 lines
17 KiB
Python
from collections import Counter, defaultdict, OrderedDict
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import os
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import sys
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import threading
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import warnings
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from django.core.exceptions import AppRegistryNotReady, ImproperlyConfigured
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from django.utils import lru_cache
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from django.utils.deprecation import RemovedInDjango19Warning
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from django.utils._os import upath
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from .config import AppConfig
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class Apps(object):
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"""
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A registry that stores the configuration of installed applications.
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It also keeps track of models eg. to provide reverse-relations.
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"""
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def __init__(self, installed_apps=()):
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# installed_apps is set to None when creating the master registry
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# because it cannot be populated at that point. Other registries must
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# provide a list of installed apps and are populated immediately.
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if installed_apps is None and hasattr(sys.modules[__name__], 'apps'):
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raise RuntimeError("You must supply an installed_apps argument.")
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# Mapping of app labels => model names => model classes. Every time a
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# model is imported, ModelBase.__new__ calls apps.register_model which
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# creates an entry in all_models. All imported models are registered,
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# regardless of whether they're defined in an installed application
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# and whether the registry has been populated. Since it isn't possible
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# to reimport a module safely (it could reexecute initialization code)
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# all_models is never overridden or reset.
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self.all_models = defaultdict(OrderedDict)
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# Mapping of labels to AppConfig instances for installed apps.
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self.app_configs = OrderedDict()
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# Stack of app_configs. Used to store the current state in
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# set_available_apps and set_installed_apps.
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self.stored_app_configs = []
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# Whether the registry is populated.
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self.apps_ready = self.models_ready = self.ready = False
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# Lock for thread-safe population.
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self._lock = threading.Lock()
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# Pending lookups for lazy relations.
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self._pending_lookups = {}
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# Populate apps and models, unless it's the master registry.
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if installed_apps is not None:
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self.populate(installed_apps)
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def populate(self, installed_apps=None):
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"""
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Loads application configurations and models.
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This method imports each application module and then each model module.
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It is thread safe and idempotent, but not reentrant.
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"""
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if self.ready:
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return
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# populate() might be called by two threads in parallel on servers
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# that create threads before initializing the WSGI callable.
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with self._lock:
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if self.ready:
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return
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# app_config should be pristine, otherwise the code below won't
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# guarantee that the order matches the order in INSTALLED_APPS.
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if self.app_configs:
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raise RuntimeError("populate() isn't reentrant")
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# Load app configs and app modules.
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for entry in installed_apps:
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if isinstance(entry, AppConfig):
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app_config = entry
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else:
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app_config = AppConfig.create(entry)
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if app_config.label in self.app_configs:
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raise ImproperlyConfigured(
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"Application labels aren't unique, "
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"duplicates: %s" % app_config.label)
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self.app_configs[app_config.label] = app_config
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# Check for duplicate app names.
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counts = Counter(
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app_config.name for app_config in self.app_configs.values())
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duplicates = [
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name for name, count in counts.most_common() if count > 1]
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if duplicates:
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raise ImproperlyConfigured(
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"Application names aren't unique, "
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"duplicates: %s" % ", ".join(duplicates))
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self.apps_ready = True
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# Load models.
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for app_config in self.app_configs.values():
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all_models = self.all_models[app_config.label]
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app_config.import_models(all_models)
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self.clear_cache()
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self.models_ready = True
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for app_config in self.get_app_configs():
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app_config.ready()
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self.ready = True
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def check_apps_ready(self):
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"""
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Raises an exception if all apps haven't been imported yet.
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"""
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if not self.apps_ready:
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raise AppRegistryNotReady("Apps aren't loaded yet.")
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def check_models_ready(self):
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"""
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Raises an exception if all models haven't been imported yet.
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"""
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if not self.models_ready:
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raise AppRegistryNotReady("Models aren't loaded yet.")
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def get_app_configs(self):
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"""
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Imports applications and returns an iterable of app configs.
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"""
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self.check_apps_ready()
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return self.app_configs.values()
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def get_app_config(self, app_label):
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"""
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Imports applications and returns an app config for the given label.
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Raises LookupError if no application exists with this label.
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"""
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self.check_apps_ready()
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try:
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return self.app_configs[app_label]
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except KeyError:
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raise LookupError("No installed app with label '%s'." % app_label)
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# This method is performance-critical at least for Django's test suite.
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@lru_cache.lru_cache(maxsize=None)
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def get_models(self, app_mod=None, include_auto_created=False,
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include_deferred=False, include_swapped=False):
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"""
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Returns a list of all installed models.
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By default, the following models aren't included:
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- auto-created models for many-to-many relations without
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an explicit intermediate table,
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- models created to satisfy deferred attribute queries,
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- models that have been swapped out.
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Set the corresponding keyword argument to True to include such models.
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"""
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self.check_models_ready()
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if app_mod:
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warnings.warn(
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"The app_mod argument of get_models is deprecated.",
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RemovedInDjango19Warning, stacklevel=2)
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app_label = app_mod.__name__.split('.')[-2]
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try:
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return list(self.get_app_config(app_label).get_models(
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include_auto_created, include_deferred, include_swapped))
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except LookupError:
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return []
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result = []
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for app_config in self.app_configs.values():
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result.extend(list(app_config.get_models(
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include_auto_created, include_deferred, include_swapped)))
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return result
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def get_model(self, app_label, model_name=None):
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"""
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Returns the model matching the given app_label and model_name.
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As a shortcut, this function also accepts a single argument in the
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form <app_label>.<model_name>.
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model_name is case-insensitive.
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Raises LookupError if no application exists with this label, or no
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model exists with this name in the application. Raises ValueError if
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called with a single argument that doesn't contain exactly one dot.
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"""
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self.check_models_ready()
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if model_name is None:
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app_label, model_name = app_label.split('.')
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return self.get_app_config(app_label).get_model(model_name.lower())
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def register_model(self, app_label, model):
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# Since this method is called when models are imported, it cannot
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# perform imports because of the risk of import loops. It mustn't
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# call get_app_config().
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model_name = model._meta.model_name
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app_models = self.all_models[app_label]
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if model_name in app_models:
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if (model.__name__ == app_models[model_name].__name__ and
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model.__module__ == app_models[model_name].__module__):
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warnings.warn(
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"Model '%s.%s' was already registered. "
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"Reloading models is not advised as it can lead to inconsistencies, "
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"most notably with related models." % (model_name, app_label),
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RuntimeWarning, stacklevel=2)
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else:
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raise RuntimeError(
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"Conflicting '%s' models in application '%s': %s and %s." %
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(model_name, app_label, app_models[model_name], model))
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app_models[model_name] = model
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self.clear_cache()
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def is_installed(self, app_name):
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"""
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Checks whether an application with this name exists in the registry.
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app_name is the full name of the app eg. 'django.contrib.admin'.
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"""
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self.check_apps_ready()
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return any(ac.name == app_name for ac in self.app_configs.values())
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def get_containing_app_config(self, object_name):
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"""
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Look for an app config containing a given object.
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object_name is the dotted Python path to the object.
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Returns the app config for the inner application in case of nesting.
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Returns None if the object isn't in any registered app config.
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"""
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# In Django 1.7 and 1.8, it's allowed to call this method at import
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# time, even while the registry is being populated. In Django 1.9 and
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# later, that should be forbidden with `self.check_apps_ready()`.
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candidates = []
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for app_config in self.app_configs.values():
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if object_name.startswith(app_config.name):
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subpath = object_name[len(app_config.name):]
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if subpath == '' or subpath[0] == '.':
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candidates.append(app_config)
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if candidates:
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return sorted(candidates, key=lambda ac: -len(ac.name))[0]
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def get_registered_model(self, app_label, model_name):
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"""
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Similar to get_model(), but doesn't require that an app exists with
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the given app_label.
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It's safe to call this method at import time, even while the registry
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is being populated.
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"""
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model = self.all_models[app_label].get(model_name.lower())
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if model is None:
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raise LookupError(
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"Model '%s.%s' not registered." % (app_label, model_name))
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return model
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def set_available_apps(self, available):
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"""
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Restricts the set of installed apps used by get_app_config[s].
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available must be an iterable of application names.
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set_available_apps() must be balanced with unset_available_apps().
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Primarily used for performance optimization in TransactionTestCase.
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This method is safe is the sense that it doesn't trigger any imports.
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"""
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available = set(available)
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installed = set(app_config.name for app_config in self.get_app_configs())
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if not available.issubset(installed):
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raise ValueError("Available apps isn't a subset of installed "
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"apps, extra apps: %s" % ", ".join(available - installed))
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self.stored_app_configs.append(self.app_configs)
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self.app_configs = OrderedDict(
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(label, app_config)
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for label, app_config in self.app_configs.items()
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if app_config.name in available)
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self.clear_cache()
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def unset_available_apps(self):
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"""
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Cancels a previous call to set_available_apps().
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"""
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self.app_configs = self.stored_app_configs.pop()
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self.clear_cache()
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def set_installed_apps(self, installed):
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"""
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Enables a different set of installed apps for get_app_config[s].
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installed must be an iterable in the same format as INSTALLED_APPS.
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set_installed_apps() must be balanced with unset_installed_apps(),
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even if it exits with an exception.
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Primarily used as a receiver of the setting_changed signal in tests.
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This method may trigger new imports, which may add new models to the
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registry of all imported models. They will stay in the registry even
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after unset_installed_apps(). Since it isn't possible to replay
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imports safely (eg. that could lead to registering listeners twice),
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models are registered when they're imported and never removed.
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"""
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if not self.ready:
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raise AppRegistryNotReady("App registry isn't ready yet.")
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self.stored_app_configs.append(self.app_configs)
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self.app_configs = OrderedDict()
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self.apps_ready = self.models_ready = self.ready = False
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self.clear_cache()
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self.populate(installed)
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def unset_installed_apps(self):
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"""
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Cancels a previous call to set_installed_apps().
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"""
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self.app_configs = self.stored_app_configs.pop()
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self.apps_ready = self.models_ready = self.ready = True
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self.clear_cache()
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def clear_cache(self):
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"""
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Clears all internal caches, for methods that alter the app registry.
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This is mostly used in tests.
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"""
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# Call expire cache on each model. This will purge
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# the relation tree and the fields cache.
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self.get_models.cache_clear()
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if self.ready:
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for model in self.get_models(include_auto_created=True):
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model._meta._expire_cache()
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### DEPRECATED METHODS GO BELOW THIS LINE ###
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def load_app(self, app_name):
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"""
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Loads the app with the provided fully qualified name, and returns the
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model module.
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"""
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warnings.warn(
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"load_app(app_name) is deprecated.",
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RemovedInDjango19Warning, stacklevel=2)
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app_config = AppConfig.create(app_name)
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app_config.import_models(self.all_models[app_config.label])
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self.app_configs[app_config.label] = app_config
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self.clear_cache()
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return app_config.models_module
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def app_cache_ready(self):
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warnings.warn(
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"app_cache_ready() is deprecated in favor of the ready property.",
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RemovedInDjango19Warning, stacklevel=2)
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return self.ready
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def get_app(self, app_label):
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"""
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Returns the module containing the models for the given app_label.
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"""
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warnings.warn(
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"get_app_config(app_label).models_module supersedes get_app(app_label).",
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RemovedInDjango19Warning, stacklevel=2)
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try:
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models_module = self.get_app_config(app_label).models_module
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except LookupError as exc:
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# Change the exception type for backwards compatibility.
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raise ImproperlyConfigured(*exc.args)
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if models_module is None:
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raise ImproperlyConfigured(
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"App '%s' doesn't have a models module." % app_label)
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return models_module
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def get_apps(self):
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"""
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Returns a list of all installed modules that contain models.
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"""
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warnings.warn(
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"[a.models_module for a in get_app_configs()] supersedes get_apps().",
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RemovedInDjango19Warning, stacklevel=2)
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app_configs = self.get_app_configs()
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return [app_config.models_module for app_config in app_configs
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if app_config.models_module is not None]
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def _get_app_package(self, app):
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return '.'.join(app.__name__.split('.')[:-1])
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def get_app_package(self, app_label):
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warnings.warn(
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"get_app_config(label).name supersedes get_app_package(label).",
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RemovedInDjango19Warning, stacklevel=2)
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return self._get_app_package(self.get_app(app_label))
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def _get_app_path(self, app):
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if hasattr(app, '__path__'): # models/__init__.py package
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app_path = app.__path__[0]
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else: # models.py module
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app_path = app.__file__
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return os.path.dirname(upath(app_path))
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def get_app_path(self, app_label):
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warnings.warn(
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"get_app_config(label).path supersedes get_app_path(label).",
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RemovedInDjango19Warning, stacklevel=2)
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return self._get_app_path(self.get_app(app_label))
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def get_app_paths(self):
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"""
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Returns a list of paths to all installed apps.
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Useful for discovering files at conventional locations inside apps
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(static files, templates, etc.)
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"""
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warnings.warn(
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"[a.path for a in get_app_configs()] supersedes get_app_paths().",
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RemovedInDjango19Warning, stacklevel=2)
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self.check_apps_ready()
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app_paths = []
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for app in self.get_apps():
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app_paths.append(self._get_app_path(app))
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return app_paths
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def register_models(self, app_label, *models):
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"""
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Register a set of models as belonging to an app.
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"""
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warnings.warn(
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"register_models(app_label, *models) is deprecated.",
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RemovedInDjango19Warning, stacklevel=2)
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for model in models:
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self.register_model(app_label, model)
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apps = Apps(installed_apps=None)
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