117 lines
4.4 KiB
Python
117 lines
4.4 KiB
Python
"Utilities for loading models and the modules that contain them."
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from django.conf import settings
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from django.core.exceptions import ImproperlyConfigured
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import sys
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import os
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__all__ = ('get_apps', 'get_app', 'get_models', 'get_model', 'register_models')
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_app_list = [] # Cache of installed apps.
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# Entry is not placed in app_list cache until entire app is loaded.
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_app_models = {} # Dictionary of models against app label
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# Each value is a dictionary of model name: model class
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# Applabel and Model entry exists in cache when individual model is loaded.
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_app_errors = {} # Dictionary of errors that were experienced when loading the INSTALLED_APPS
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# Key is the app_name of the model, value is the exception that was raised
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# during model loading.
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_loaded = False # Has the contents of settings.INSTALLED_APPS been loaded?
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# i.e., has get_apps() been called?
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def get_apps():
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"Returns a list of all installed modules that contain models."
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global _app_list
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global _loaded
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if not _loaded:
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_loaded = True
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for app_name in settings.INSTALLED_APPS:
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try:
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load_app(app_name)
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except Exception, e:
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# Problem importing the app
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_app_errors[app_name] = e
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return _app_list
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def get_app(app_label, emptyOK=False):
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"Returns the module containing the models for the given app_label. If the app has no models in it and 'emptyOK' is True, returns None."
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get_apps() # Run get_apps() to populate the _app_list cache. Slightly hackish.
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for app_name in settings.INSTALLED_APPS:
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if app_label == app_name.split('.')[-1]:
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mod = load_app(app_name)
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if mod is None:
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if emptyOK:
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return None
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else:
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return mod
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raise ImproperlyConfigured, "App with label %s could not be found" % app_label
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def load_app(app_name):
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"Loads the app with the provided fully qualified name, and returns the model module."
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global _app_list
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mod = __import__(app_name, {}, {}, ['models'])
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if not hasattr(mod, 'models'):
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return None
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if mod.models not in _app_list:
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_app_list.append(mod.models)
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return mod.models
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def get_app_errors():
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"Returns the map of known problems with the INSTALLED_APPS"
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global _app_errors
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get_apps() # Run get_apps() to populate the _app_list cache. Slightly hackish.
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return _app_errors
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def get_models(app_mod=None):
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"""
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Given a module containing models, returns a list of the models. Otherwise
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returns a list of all installed models.
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"""
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app_list = get_apps() # Run get_apps() to populate the _app_list cache. Slightly hackish.
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if app_mod:
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return _app_models.get(app_mod.__name__.split('.')[-2], {}).values()
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else:
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model_list = []
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for app_mod in app_list:
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model_list.extend(get_models(app_mod))
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return model_list
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def get_model(app_label, model_name, seed_cache=True):
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"""
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Returns the model matching the given app_label and case-insensitive
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model_name.
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Returns None if no model is found.
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"""
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if seed_cache:
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get_apps()
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try:
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model_dict = _app_models[app_label]
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except KeyError:
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return None
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try:
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return model_dict[model_name.lower()]
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except KeyError:
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return None
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def register_models(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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for model in models:
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# Store as 'name: model' pair in a dictionary
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# in the _app_models dictionary
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model_name = model._meta.object_name.lower()
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model_dict = _app_models.setdefault(app_label, {})
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if model_dict.has_key(model_name):
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# The same model may be imported via different paths (e.g.
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# appname.models and project.appname.models). We use the source
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# filename as a means to detect identity.
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fname1 = os.path.abspath(sys.modules[model.__module__].__file__)
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fname2 = os.path.abspath(sys.modules[model_dict[model_name].__module__].__file__)
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# Since the filename extension could be .py the first time and .pyc
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# or .pyo the second time, ignore the extension when comparing.
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if os.path.splitext(fname1)[0] == os.path.splitext(fname2)[0]:
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continue
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model_dict[model_name] = model
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