Fixed #17061 -- Factored out importing object from a dotted path

Thanks Carl Meyer for the report.
2025-10-31 01:25:32 +00:00 · 2013-02-02 22:58:02 +01:00
parent 3f1c7b7053
commit 7c5b244826
26 changed files with 116 additions and 255 deletions
--- a/django/conf/init.py
+++ b/django/conf/init.py
@@ -15,6 +15,7 @@ from django.conf import global_settings
 from django.core.exceptions import ImproperlyConfigured
 from django.utils.functional import LazyObject, empty
 from django.utils import importlib
+from django.utils.module_loading import import_by_path
 from django.utils import six

 ENVIRONMENT_VARIABLE = "DJANGO_SETTINGS_MODULE"
@@ -68,9 +69,7 @@ class LazySettings(LazyObject):
        if self.LOGGING_CONFIG:
            from django.utils.log import DEFAULT_LOGGING
            # First find the logging configuration function ...
-            logging_config_path, logging_config_func_name = self.LOGGING_CONFIG.rsplit('.', 1)
-            logging_config_module = importlib.import_module(logging_config_path)
-            logging_config_func = getattr(logging_config_module, logging_config_func_name)
+            logging_config_func = import_by_path(self.LOGGING_CONFIG)

            logging_config_func(DEFAULT_LOGGING)

--- a/django/contrib/admin/tests.py
+++ b/django/contrib/admin/tests.py
@@ -1,5 +1,5 @@
 from django.test import LiveServerTestCase
-from django.utils.importlib import import_module
+from django.utils.module_loading import import_by_path
 from django.utils.unittest import SkipTest
 from django.utils.translation import ugettext as _

@@ -9,11 +9,7 @@ class AdminSeleniumWebDriverTestCase(LiveServerTestCase):
    @classmethod
    def setUpClass(cls):
        try:
-            # Import and start the WebDriver class.
-            module, attr = cls.webdriver_class.rsplit('.', 1)
-            mod = import_module(module)
-            WebDriver = getattr(mod, attr)
-            cls.selenium = WebDriver()
+            cls.selenium = import_by_path(cls.webdriver_class)()
        except Exception as e:
            raise SkipTest('Selenium webdriver "%s" not installed or not '
                           'operational: %s' % (cls.webdriver_class, str(e)))
--- a/django/contrib/auth/init.py
+++ b/django/contrib/auth/init.py
@@ -1,8 +1,8 @@
 import re

-from django.core.exceptions import ImproperlyConfigured, PermissionDenied
-from django.utils.importlib import import_module
 from django.contrib.auth.signals import user_logged_in, user_logged_out, user_login_failed
+from django.core.exceptions import ImproperlyConfigured, PermissionDenied
+from django.utils.module_loading import import_by_path

 SESSION_KEY = '_auth_user_id'
 BACKEND_SESSION_KEY = '_auth_user_backend'
@@ -10,19 +10,7 @@ REDIRECT_FIELD_NAME = 'next'


 def load_backend(path):
-    i = path.rfind('.')
-    module, attr = path[:i], path[i + 1:]
-    try:
-        mod = import_module(module)
-    except ImportError as e:
-        raise ImproperlyConfigured('Error importing authentication backend %s: "%s"' % (path, e))
-    except ValueError:
-        raise ImproperlyConfigured('Error importing authentication backends. Is AUTHENTICATION_BACKENDS a correctly defined list or tuple?')
-    try:
-        cls = getattr(mod, attr)
-    except AttributeError:
-        raise ImproperlyConfigured('Module "%s" does not define a "%s" authentication backend' % (module, attr))
-    return cls()
+    return import_by_path(path)()


 def get_backends():
--- a/django/contrib/auth/hashers.py
+++ b/django/contrib/auth/hashers.py
@@ -12,6 +12,7 @@ from django.utils.encoding import force_bytes, force_str
 from django.core.exceptions import ImproperlyConfigured
 from django.utils.crypto import (
    pbkdf2, constant_time_compare, get_random_string)
+from django.utils.module_loading import import_by_path
 from django.utils.translation import ugettext_noop as _


@@ -84,13 +85,7 @@ def load_hashers(password_hashers=None):
    if not password_hashers:
        password_hashers = settings.PASSWORD_HASHERS
    for backend in password_hashers:
-        try:
-            mod_path, cls_name = backend.rsplit('.', 1)
-            mod = importlib.import_module(mod_path)
-            hasher_cls = getattr(mod, cls_name)
-        except (AttributeError, ImportError, ValueError):
-            raise ImproperlyConfigured("hasher not found: %s" % backend)
-        hasher = hasher_cls()
+        hasher = import_by_path(backend)()
        if not getattr(hasher, 'algorithm'):
            raise ImproperlyConfigured("hasher doesn't specify an "
                                       "algorithm name: %s" % backend)
--- a/django/contrib/formtools/tests/wizard/loadstorage.py
+++ b/django/contrib/formtools/tests/wizard/loadstorage.py
@@ -1,8 +1,6 @@
 from django.test import TestCase

-from django.contrib.formtools.wizard.storage import (get_storage,
-                                                     MissingStorageModule,
-                                                     MissingStorageClass)
+from django.contrib.formtools.wizard.storage import get_storage, MissingStorage
 from django.contrib.formtools.wizard.storage.base import BaseStorage


@@ -12,11 +10,9 @@ class TestLoadStorage(TestCase):
            type(get_storage('django.contrib.formtools.wizard.storage.base.BaseStorage', 'wizard1')),
            BaseStorage)

-    def test_missing_module(self):
-        self.assertRaises(MissingStorageModule, get_storage,
+    def test_missing_storage(self):
+        self.assertRaises(MissingStorage, get_storage,
            'django.contrib.formtools.wizard.storage.idontexist.IDontExistStorage', 'wizard1')
-
-    def test_missing_class(self):
-        self.assertRaises(MissingStorageClass, get_storage,
+        self.assertRaises(MissingStorage, get_storage,
            'django.contrib.formtools.wizard.storage.base.IDontExistStorage', 'wizard1')

--- a/django/contrib/formtools/wizard/storage/init.py
+++ b/django/contrib/formtools/wizard/storage/init.py
@@ -1,22 +1,14 @@
-from django.utils.importlib import import_module
+from django.core.exceptions import ImproperlyConfigured
+from django.utils.module_loading import import_by_path

 from django.contrib.formtools.wizard.storage.base import BaseStorage
 from django.contrib.formtools.wizard.storage.exceptions import (
-    MissingStorageModule, MissingStorageClass, NoFileStorageConfigured)
+    MissingStorage, NoFileStorageConfigured)


 def get_storage(path, *args, **kwargs):
-    i = path.rfind('.')
-    module, attr = path[:i], path[i+1:]
    try:
-        mod = import_module(module)
-    except ImportError as e:
-        raise MissingStorageModule(
-            'Error loading storage %s: "%s"' % (module, e))
-    try:
-        storage_class = getattr(mod, attr)
-    except AttributeError:
-        raise MissingStorageClass(
-            'Module "%s" does not define a storage named "%s"' % (module, attr))
+        storage_class = import_by_path(path)
+    except ImproperlyConfigured as e:
+        raise MissingStorage('Error loading storage: %s' % e)
    return storage_class(*args, **kwargs)
-
--- a/django/contrib/formtools/wizard/storage/exceptions.py
+++ b/django/contrib/formtools/wizard/storage/exceptions.py
@@ -1,9 +1,6 @@
 from django.core.exceptions import ImproperlyConfigured

-class MissingStorageModule(ImproperlyConfigured):
-    pass
-
-class MissingStorageClass(ImproperlyConfigured):
+class MissingStorage(ImproperlyConfigured):
    pass

 class NoFileStorageConfigured(ImproperlyConfigured):
--- a/django/contrib/messages/storage/init.py
+++ b/django/contrib/messages/storage/init.py
@@ -1,28 +1,5 @@
 from django.conf import settings
-from django.core.exceptions import ImproperlyConfigured
-from django.utils.importlib import import_module
-
-
-def get_storage(import_path):
-    """
-    Imports the message storage class described by import_path, where
-    import_path is the full Python path to the class.
-    """
-    try:
-        dot = import_path.rindex('.')
-    except ValueError:
-        raise ImproperlyConfigured("%s isn't a Python path." % import_path)
-    module, classname = import_path[:dot], import_path[dot + 1:]
-    try:
-        mod = import_module(module)
-    except ImportError as e:
-        raise ImproperlyConfigured('Error importing module %s: "%s"' %
-                                   (module, e))
-    try:
-        return getattr(mod, classname)
-    except AttributeError:
-        raise ImproperlyConfigured('Module "%s" does not define a "%s" '
-                                   'class.' % (module, classname))
+from django.utils.module_loading import import_by_path as get_storage


 # Callable with the same interface as the storage classes i.e.  accepts a
--- a/django/contrib/staticfiles/finders.py
+++ b/django/contrib/staticfiles/finders.py
@@ -4,7 +4,7 @@ from django.core.exceptions import ImproperlyConfigured
 from django.core.files.storage import default_storage, Storage, FileSystemStorage
 from django.utils.datastructures import SortedDict
 from django.utils.functional import empty, memoize, LazyObject
-from django.utils.importlib import import_module
+from django.utils.module_loading import import_by_path
 from django.utils._os import safe_join
 from django.utils import six

@@ -258,17 +258,7 @@ def _get_finder(import_path):
    Imports the staticfiles finder class described by import_path, where
    import_path is the full Python path to the class.
    """
-    module, attr = import_path.rsplit('.', 1)
-    try:
-        mod = import_module(module)
-    except ImportError as e:
-        raise ImproperlyConfigured('Error importing module %s: "%s"' %
-                                   (module, e))
-    try:
-        Finder = getattr(mod, attr)
-    except AttributeError:
-        raise ImproperlyConfigured('Module "%s" does not define a "%s" '
-                                   'class.' % (module, attr))
+    Finder = import_by_path(import_path)
    if not issubclass(Finder, BaseFinder):
        raise ImproperlyConfigured('Finder "%s" is not a subclass of "%s"' %
                                   (Finder, BaseFinder))
--- a/django/core/cache/init.py
+++ b/django/core/cache/init.py
@@ -25,6 +25,8 @@ from django.core.cache.backends.base import (
    InvalidCacheBackendError, CacheKeyWarning, BaseCache)
 from django.core.exceptions import ImproperlyConfigured
 from django.utils import importlib
+from django.utils.module_loading import import_by_path
+

 __all__ = [
    'get_cache', 'cache', 'DEFAULT_CACHE_ALIAS'
@@ -86,11 +88,10 @@ def parse_backend_conf(backend, **kwargs):
    else:
        try:
            # Trying to import the given backend, in case it's a dotted path
-            mod_path, cls_name = backend.rsplit('.', 1)
-            mod = importlib.import_module(mod_path)
-            backend_cls = getattr(mod, cls_name)
-        except (AttributeError, ImportError, ValueError):
-            raise InvalidCacheBackendError("Could not find backend '%s'" % backend)
+            backend_cls = import_by_path(backend)
+        except ImproperlyConfigured as e:
+            raise InvalidCacheBackendError("Could not find backend '%s': %s" % (
+                backend, e))
        location = kwargs.pop('LOCATION', '')
        return backend, location, kwargs

@@ -126,10 +127,8 @@ def get_cache(backend, **kwargs):
            backend_cls = mod.CacheClass
        else:
            backend, location, params = parse_backend_conf(backend, **kwargs)
-            mod_path, cls_name = backend.rsplit('.', 1)
-            mod = importlib.import_module(mod_path)
-            backend_cls = getattr(mod, cls_name)
-    except (AttributeError, ImportError) as e:
+            backend_cls = import_by_path(backend)
+    except (AttributeError, ImportError, ImproperlyConfigured) as e:
        raise InvalidCacheBackendError(
            "Could not find backend '%s': %s" % (backend, e))
    cache = backend_cls(location, params)
--- a/django/core/cache/backends/base.py
+++ b/django/core/cache/backends/base.py
@@ -4,7 +4,7 @@ from __future__ import unicode_literals
 import warnings

 from django.core.exceptions import ImproperlyConfigured, DjangoRuntimeWarning
-from django.utils.importlib import import_module
+from django.utils.module_loading import import_by_path


 class InvalidCacheBackendError(ImproperlyConfigured):
@@ -40,9 +40,7 @@ def get_key_func(key_func):
        if callable(key_func):
            return key_func
        else:
-            key_func_module_path, key_func_name = key_func.rsplit('.', 1)
-            key_func_module = import_module(key_func_module_path)
-            return getattr(key_func_module, key_func_name)
+            return import_by_path(key_func)
    return default_key_func


--- a/django/core/files/storage.py
+++ b/django/core/files/storage.py
@@ -8,12 +8,12 @@ import itertools
 from datetime import datetime

 from django.conf import settings
-from django.core.exceptions import ImproperlyConfigured, SuspiciousOperation
+from django.core.exceptions import SuspiciousOperation
 from django.core.files import locks, File
 from django.core.files.move import file_move_safe
 from django.utils.encoding import force_text, filepath_to_uri
 from django.utils.functional import LazyObject
-from django.utils.importlib import import_module
+from django.utils.module_loading import import_by_path
 from django.utils.text import get_valid_filename
 from django.utils._os import safe_join, abspathu

@@ -277,21 +277,7 @@ class FileSystemStorage(Storage):
        return datetime.fromtimestamp(os.path.getmtime(self.path(name)))

 def get_storage_class(import_path=None):
-    if import_path is None:
-        import_path = settings.DEFAULT_FILE_STORAGE
-    try:
-        dot = import_path.rindex('.')
-    except ValueError:
-        raise ImproperlyConfigured("%s isn't a storage module." % import_path)
-    module, classname = import_path[:dot], import_path[dot+1:]
-    try:
-        mod = import_module(module)
-    except ImportError as e:
-        raise ImproperlyConfigured('Error importing storage module %s: "%s"' % (module, e))
-    try:
-        return getattr(mod, classname)
-    except AttributeError:
-        raise ImproperlyConfigured('Storage module "%s" does not define a "%s" class.' % (module, classname))
+    return import_by_path(import_path or settings.DEFAULT_FILE_STORAGE)

 class DefaultStorage(LazyObject):
    def _setup(self):
--- a/django/core/files/uploadhandler.py
+++ b/django/core/files/uploadhandler.py
@@ -7,10 +7,9 @@ from __future__ import unicode_literals
 from io import BytesIO

 from django.conf import settings
-from django.core.exceptions import ImproperlyConfigured
 from django.core.files.uploadedfile import TemporaryUploadedFile, InMemoryUploadedFile
-from django.utils import importlib
 from django.utils.encoding import python_2_unicode_compatible
+from django.utils.module_loading import import_by_path

 __all__ = ['UploadFileException','StopUpload', 'SkipFile', 'FileUploadHandler',
           'TemporaryFileUploadHandler', 'MemoryFileUploadHandler',
@@ -201,17 +200,4 @@ def load_handler(path, *args, **kwargs):
        <TemporaryFileUploadHandler object at 0x...>

    """
-    i = path.rfind('.')
-    module, attr = path[:i], path[i+1:]
-    try:
-        mod = importlib.import_module(module)
-    except ImportError as e:
-        raise ImproperlyConfigured('Error importing upload handler module %s: "%s"' % (module, e))
-    except ValueError:
-        raise ImproperlyConfigured('Error importing upload handler module.'
-            'Is FILE_UPLOAD_HANDLERS a correctly defined list or tuple?')
-    try:
-        cls = getattr(mod, attr)
-    except AttributeError:
-        raise ImproperlyConfigured('Module "%s" does not define a "%s" upload handler backend' % (module, attr))
-    return cls(*args, **kwargs)
+    return import_by_path(path)(*args, **kwargs)
--- a/django/core/handlers/base.py
+++ b/django/core/handlers/base.py
@@ -9,8 +9,9 @@ from django.conf import settings
 from django.core import exceptions
 from django.core import urlresolvers
 from django.core import signals
+from django.core.exceptions import MiddlewareNotUsed, PermissionDenied
 from django.utils.encoding import force_text
-from django.utils.importlib import import_module
+from django.utils.module_loading import import_by_path
 from django.utils import six
 from django.views import debug

@@ -43,21 +44,10 @@ class BaseHandler(object):

        request_middleware = []
        for middleware_path in settings.MIDDLEWARE_CLASSES:
-            try:
-                mw_module, mw_classname = middleware_path.rsplit('.', 1)
-            except ValueError:
-                raise exceptions.ImproperlyConfigured('%s isn\'t a middleware module' % middleware_path)
-            try:
-                mod = import_module(mw_module)
-            except ImportError as e:
-                raise exceptions.ImproperlyConfigured('Error importing middleware %s: "%s"' % (mw_module, e))
-            try:
-                mw_class = getattr(mod, mw_classname)
-            except AttributeError:
-                raise exceptions.ImproperlyConfigured('Middleware module "%s" does not define a "%s" class' % (mw_module, mw_classname))
+            mw_class = import_by_path(middleware_path)
            try:
                mw_instance = mw_class()
-            except exceptions.MiddlewareNotUsed:
+            except MiddlewareNotUsed:
                continue

            if hasattr(mw_instance, 'process_request'):
@@ -154,7 +144,7 @@ class BaseHandler(object):
                    except:
                        signals.got_request_exception.send(sender=self.__class__, request=request)
                        response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
-            except exceptions.PermissionDenied:
+            except PermissionDenied:
                logger.warning(
                    'Forbidden (Permission denied): %s', request.path,
                    extra={
--- a/django/core/mail/init.py
+++ b/django/core/mail/init.py
@@ -4,8 +4,7 @@ Tools for sending email.
 from __future__ import unicode_literals

 from django.conf import settings
-from django.core.exceptions import ImproperlyConfigured
-from django.utils.importlib import import_module
+from django.utils.module_loading import import_by_path

 # Imported for backwards compatibility, and for the sake
 # of a cleaner namespace. These symbols used to be in
@@ -27,18 +26,7 @@ def get_connection(backend=None, fail_silently=False, **kwds):
    Both fail_silently and other keyword arguments are used in the
    constructor of the backend.
    """
-    path = backend or settings.EMAIL_BACKEND
-    try:
-        mod_name, klass_name = path.rsplit('.', 1)
-        mod = import_module(mod_name)
-    except ImportError as e:
-        raise ImproperlyConfigured(('Error importing email backend module %s: "%s"'
-                                    % (mod_name, e)))
-    try:
-        klass = getattr(mod, klass_name)
-    except AttributeError:
-        raise ImproperlyConfigured(('Module "%s" does not define a '
-                                    '"%s" class' % (mod_name, klass_name)))
+    klass = import_by_path(backend or settings.EMAIL_BACKEND)
    return klass(fail_silently=fail_silently, **kwds)


--- a/django/core/servers/basehttp.py
+++ b/django/core/servers/basehttp.py
@@ -21,11 +21,9 @@ from django.utils.six.moves import socketserver
 from wsgiref import simple_server
 from wsgiref.util import FileWrapper   # for backwards compatibility

-import django
-from django.core.exceptions import ImproperlyConfigured
 from django.core.management.color import color_style
 from django.core.wsgi import get_wsgi_application
-from django.utils.importlib import import_module
+from django.utils.module_loading import import_by_path

 __all__ = ['WSGIServer', 'WSGIRequestHandler']

@@ -49,22 +47,11 @@ def get_internal_wsgi_application():
    app_path = getattr(settings, 'WSGI_APPLICATION')
    if app_path is None:
        return get_wsgi_application()
-    module_name, attr = app_path.rsplit('.', 1)
-    try:
-        mod = import_module(module_name)
-    except ImportError as e:
-        raise ImproperlyConfigured(
-            "WSGI application '%s' could not be loaded; "
-            "could not import module '%s': %s" % (app_path, module_name, e))
-    try:
-        app = getattr(mod, attr)
-    except AttributeError as e:
-        raise ImproperlyConfigured(
-            "WSGI application '%s' could not be loaded; "
-            "can't find '%s' in module '%s': %s"
-            % (app_path, attr, module_name, e))

-    return app
+    return import_by_path(
+        app_path,
+        error_prefix="WSGI application '%s' could not be loaded; " % app_path
+    )


 class WSGIServerException(Exception):
--- a/django/core/signing.py
+++ b/django/core/signing.py
@@ -41,11 +41,10 @@ import time
 import zlib

 from django.conf import settings
-from django.core.exceptions import ImproperlyConfigured
 from django.utils import baseconv
 from django.utils.crypto import constant_time_compare, salted_hmac
 from django.utils.encoding import force_bytes, force_str, force_text
-from django.utils.importlib import import_module
+from django.utils.module_loading import import_by_path


 class BadSignature(Exception):
@@ -76,18 +75,7 @@ def base64_hmac(salt, value, key):


 def get_cookie_signer(salt='django.core.signing.get_cookie_signer'):
-    modpath = settings.SIGNING_BACKEND
-    module, attr = modpath.rsplit('.', 1)
-    try:
-        mod = import_module(module)
-    except ImportError as e:
-        raise ImproperlyConfigured(
-            'Error importing cookie signer %s: "%s"' % (modpath, e))
-    try:
-        Signer = getattr(mod, attr)
-    except AttributeError as e:
-        raise ImproperlyConfigured(
-            'Error importing cookie signer %s: "%s"' % (modpath, e))
+    Signer = import_by_path(settings.SIGNING_BACKEND)
    return Signer('django.http.cookies' + settings.SECRET_KEY, salt=salt)


--- a/django/db/utils.py
+++ b/django/db/utils.py
@@ -5,6 +5,7 @@ from threading import local
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django.utils.importlib import import_module
+from django.utils.module_loading import import_by_path
 from django.utils._os import upath
 from django.utils import six

@@ -110,17 +111,7 @@ class ConnectionRouter(object):
        self.routers = []
        for r in routers:
            if isinstance(r, six.string_types):
-                try:
-                    module_name, klass_name = r.rsplit('.', 1)
-                    module = import_module(module_name)
-                except ImportError as e:
-                    raise ImproperlyConfigured('Error importing database router %s: "%s"' % (klass_name, e))
-                try:
-                    router_class = getattr(module, klass_name)
-                except AttributeError:
-                    raise ImproperlyConfigured('Module "%s" does not define a database router name "%s"' % (module, klass_name))
-                else:
-                    router = router_class()
+                router = import_by_path(r)()
            else:
                router = r
            self.routers.append(router)
--- a/django/template/context.py
+++ b/django/template/context.py
@@ -1,6 +1,5 @@
 from copy import copy
-from django.core.exceptions import ImproperlyConfigured
-from django.utils.importlib import import_module
+from django.utils.module_loading import import_by_path

 # Cache of actual callables.
 _standard_context_processors = None
@@ -146,16 +145,7 @@ def get_standard_processors():
        collect.extend(_builtin_context_processors)
        collect.extend(settings.TEMPLATE_CONTEXT_PROCESSORS)
        for path in collect:
-            i = path.rfind('.')
-            module, attr = path[:i], path[i+1:]
-            try:
-                mod = import_module(module)
-            except ImportError as e:
-                raise ImproperlyConfigured('Error importing request processor module %s: "%s"' % (module, e))
-            try:
-                func = getattr(mod, attr)
-            except AttributeError:
-                raise ImproperlyConfigured('Module "%s" does not define a "%s" callable request processor' % (module, attr))
+            func = import_by_path(path)
            processors.append(func)
        _standard_context_processors = tuple(processors)
    return _standard_context_processors
--- a/django/template/loader.py
+++ b/django/template/loader.py
@@ -27,8 +27,8 @@

 from django.core.exceptions import ImproperlyConfigured
 from django.template.base import Origin, Template, Context, TemplateDoesNotExist, add_to_builtins
-from django.utils.importlib import import_module
 from django.conf import settings
+from django.utils.module_loading import import_by_path
 from django.utils import six

 template_source_loaders = None
@@ -91,15 +91,7 @@ def find_template_loader(loader):
    else:
        args = []
    if isinstance(loader, six.string_types):
-        module, attr = loader.rsplit('.', 1)
-        try:
-            mod = import_module(module)
-        except ImportError as e:
-            raise ImproperlyConfigured('Error importing template source loader %s: "%s"' % (loader, e))
-        try:
-            TemplateLoader = getattr(mod, attr)
-        except AttributeError as e:
-            raise ImproperlyConfigured('Error importing template source loader %s: "%s"' % (loader, e))
+        TemplateLoader = import_by_path(loader)

        if hasattr(TemplateLoader, 'load_template_source'):
            func = TemplateLoader(*args)
--- a/django/utils/module_loading.py
+++ b/django/utils/module_loading.py
@@ -2,6 +2,32 @@ import imp
 import os
 import sys

+from django.core.exceptions import ImproperlyConfigured
+from django.utils.importlib import import_module
+
+
+def import_by_path(dotted_path, error_prefix=''):
+    """
+    Import a dotted module path and return the attribute/class designated by the
+    last name in the path. Raise ImproperlyConfigured if something goes wrong.
+    """
+    try:
+        module_path, class_name = dotted_path.rsplit('.', 1)
+    except ValueError:
+        raise ImproperlyConfigured("%s%s doesn't look like a module path" % (
+            error_prefix, dotted_path))
+    try:
+        module = import_module(module_path)
+    except ImportError as e:
+        raise ImproperlyConfigured('%sError importing module %s: "%s"' % (
+            error_prefix, module_path, e))
+    try:
+        attr = getattr(module, class_name)
+    except AttributeError:
+        raise ImproperlyConfigured('%sModule "%s" does not define a "%s" attribute/class' % (
+            error_prefix, module_path, class_name))
+    return attr
+

 def module_has_submodule(package, module_name):
    """See if 'module' is in 'package'."""
--- a/django/views/debug.py
+++ b/django/views/debug.py
@@ -13,8 +13,8 @@ from django.http import (HttpResponse, HttpResponseServerError,
 from django.template import Template, Context, TemplateDoesNotExist
 from django.template.defaultfilters import force_escape, pprint
 from django.utils.html import escape
-from django.utils.importlib import import_module
 from django.utils.encoding import force_bytes, smart_text
+from django.utils.module_loading import import_by_path
 from django.utils import six

 HIDDEN_SETTINGS = re.compile('API|TOKEN|KEY|SECRET|PASS|PROFANITIES_LIST|SIGNATURE')
@@ -76,17 +76,8 @@ def get_exception_reporter_filter(request):
    global default_exception_reporter_filter
    if default_exception_reporter_filter is None:
        # Load the default filter for the first time and cache it.
-        modpath = settings.DEFAULT_EXCEPTION_REPORTER_FILTER
-        modname, classname = modpath.rsplit('.', 1)
-        try:
-            mod = import_module(modname)
-        except ImportError as e:
-            raise ImproperlyConfigured(
-            'Error importing default exception reporter filter %s: "%s"' % (modpath, e))
-        try:
-            default_exception_reporter_filter = getattr(mod, classname)()
-        except AttributeError:
-            raise ImproperlyConfigured('Default exception reporter filter module "%s" does not define a "%s" class' % (modname, classname))
+        default_exception_reporter_filter = import_by_path(
+            settings.DEFAULT_EXCEPTION_REPORTER_FILTER)()
    if request:
        return getattr(request, 'exception_reporter_filter', default_exception_reporter_filter)
    else:
--- a/tests/regressiontests/file_storage/tests.py
+++ b/tests/regressiontests/file_storage/tests.py
@@ -57,9 +57,9 @@ class GetStorageClassTests(SimpleTestCase):
        """
        self.assertRaisesMessage(
            ImproperlyConfigured,
-            "NonExistingStorage isn't a storage module.",
+            "Error importing module storage: \"No module named storage\"",
            get_storage_class,
-            'NonExistingStorage')
+            'storage.NonExistingStorage')

    def test_get_nonexisting_storage_class(self):
        """
@@ -67,8 +67,8 @@ class GetStorageClassTests(SimpleTestCase):
        """
        self.assertRaisesMessage(
            ImproperlyConfigured,
-            'Storage module "django.core.files.storage" does not define a '\
-                '"NonExistingStorage" class.',
+            'Module "django.core.files.storage" does not define a '
+            '"NonExistingStorage" attribute/class',
            get_storage_class,
            'django.core.files.storage.NonExistingStorage')

@@ -79,8 +79,8 @@ class GetStorageClassTests(SimpleTestCase):
        # Error message may or may not be the fully qualified path.
        six.assertRaisesRegex(self,
            ImproperlyConfigured,
-            ('Error importing storage module django.core.files.non_existing_'
-                'storage: "No module named .*non_existing_storage'),
+            'Error importing module django.core.files.non_existing_storage: '
+            '"No module named non_existing_storage"',
            get_storage_class,
            'django.core.files.non_existing_storage.NonExistingStorage'
        )
--- a/tests/regressiontests/utils/module_loading.py
+++ b/tests/regressiontests/utils/module_loading.py
@@ -3,9 +3,10 @@ import sys
 import imp
 from zipimport import zipimporter

+from django.core.exceptions import ImproperlyConfigured
 from django.utils import unittest
 from django.utils.importlib import import_module
-from django.utils.module_loading import module_has_submodule
+from django.utils.module_loading import import_by_path, module_has_submodule
 from django.utils._os import upath


@@ -103,6 +104,23 @@ class EggLoader(unittest.TestCase):
        self.assertFalse(module_has_submodule(egg_module, 'no_such_module'))
        self.assertRaises(ImportError, import_module, 'egg_module.sub1.sub2.no_such_module')

+
+class ModuleImportTestCase(unittest.TestCase):
+    def test_import_by_path(self):
+        cls = import_by_path(
+            'django.utils.module_loading.import_by_path')
+        self.assertEqual(cls, import_by_path)
+
+        # Test exceptions raised
+        for path in ('no_dots_in_path', 'unexistent.path',
+                'tests.regressiontests.utils.unexistent'):
+            self.assertRaises(ImproperlyConfigured, import_by_path, path)
+
+        with self.assertRaises(ImproperlyConfigured) as cm:
+            import_by_path('unexistent.module.path', error_prefix="Foo")
+        self.assertTrue(str(cm.exception).startswith('Foo'))
+
+
 class ProxyFinder(object):
    def __init__(self):
        self._cache = {}
--- a/tests/regressiontests/utils/tests.py
+++ b/tests/regressiontests/utils/tests.py
@@ -20,7 +20,8 @@ from .html import TestUtilsHtml
 from .http import TestUtilsHttp, ETagProcessingTests, HttpDateProcessingTests
 from .ipv6 import TestUtilsIPv6
 from .jslex import JsToCForGettextTest, JsTokensTest
-from .module_loading import CustomLoader, DefaultLoader, EggLoader
+from .module_loading import (CustomLoader, DefaultLoader, EggLoader,
+    ModuleImportTestCase)
 from .numberformat import TestNumberFormat
 from .os_utils import SafeJoinTests
 from .regex_helper import NormalizeTests
--- a/tests/regressiontests/wsgi/tests.py
+++ b/tests/regressiontests/wsgi/tests.py
@@ -85,7 +85,7 @@ class GetInternalWSGIApplicationTest(unittest.TestCase):
    def test_bad_module(self):
        with six.assertRaisesRegex(self,
            ImproperlyConfigured,
-            r"^WSGI application 'regressiontests.wsgi.noexist.app' could not be loaded; could not import module 'regressiontests.wsgi.noexist':"):
+            r"^WSGI application 'regressiontests.wsgi.noexist.app' could not be loaded; Error importing.*"):

            get_internal_wsgi_application()

@@ -94,6 +94,6 @@ class GetInternalWSGIApplicationTest(unittest.TestCase):
    def test_bad_name(self):
        with six.assertRaisesRegex(self,
            ImproperlyConfigured,
-            r"^WSGI application 'regressiontests.wsgi.wsgi.noexist' could not be loaded; can't find 'noexist' in module 'regressiontests.wsgi.wsgi':"):
+            r"^WSGI application 'regressiontests.wsgi.wsgi.noexist' could not be loaded; Module.*"):

            get_internal_wsgi_application()