Allow callable as config_loader_path

Author: mhindery

djangosaml2/conf.py

@@ -15,55 +15,51 @@
 
 import copy
 from importlib import import_module
+from typing import Callable, Optional, Union
 
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
+from django.http import HttpRequest
+from django.utils.module_loading import import_string
 from saml2.config import SPConfig
 
 from .utils import get_custom_setting
 
 
-def get_config_loader(path, request=None):
-    i = path.rfind('.')
-    module, attr = path[:i], path[i + 1:]
+def get_config_loader(path: str) -> Callable:
+    """ Import the function at a given path and return it
+    """
     try:
-        mod = import_module(module)
+        config_loader = import_string(path)
     except ImportError as e:
-        raise ImproperlyConfigured(
-            'Error importing SAML config loader %s: "%s"' % (path, e))
-    except ValueError as e:
-        raise ImproperlyConfigured(
-            'Error importing SAML config loader. Is SAML_CONFIG_LOADER '
-            'a correctly string with a callable path?'
-            )
-    try:
-        config_loader = getattr(mod, attr)
-    except AttributeError:
-        raise ImproperlyConfigured(
-            'Module "%s" does not define a "%s" config loader' %
-            (module, attr)
-            )
+        raise ImproperlyConfigured(f'Error importing SAML config loader {path}: "{e}"')
 
-    if not hasattr(config_loader, '__call__'):
-        raise ImproperlyConfigured(
-            "SAML config loader must be a callable object.")
+    if not callable(config_loader):
+        raise ImproperlyConfigured("SAML config loader must be a callable object.")
 
     return config_loader
 
 
-def config_settings_loader(request=None):
-    """Utility function to load the pysaml2 configuration.
-
-    This is also the default config loader.
+def config_settings_loader(request: Optional[HttpRequest] = None) -> SPConfig:
+    """ Utility function to load the pysaml2 configuration.
+        The configuration can be modified based on the request being passed.
+        This is the default config loader, which just loads the config from the settings.
     """
     conf = SPConfig()
     conf.load(copy.deepcopy(settings.SAML_CONFIG))
     return conf
 
 
-def get_config(config_loader_path=None, request=None):
-    config_loader_path = config_loader_path or get_custom_setting(
-        'SAML_CONFIG_LOADER', 'djangosaml2.conf.config_settings_loader')
+def get_config(config_loader_path: Optional[Union[Callable, str]] = None, request: Optional[HttpRequest] = None) -> SPConfig:
+    """ Load a config_loader function if necessary, and call that function with the request as argument.
+        If the config_loader_path is a callable instead of a string, no importing is necessary and it will be used directly.
+        Return the resulting SPConfig.
+    """
+    config_loader_path = config_loader_path or get_custom_setting('SAML_CONFIG_LOADER', 'djangosaml2.conf.config_settings_loader')
+
+    if callable(config_loader_path):
+        config_loader = config_loader_path
+    else:
+        config_loader = get_config_loader(config_loader_path)
 
-    config_loader = get_config_loader(config_loader_path)
     return config_loader(request)

djangosaml2/tests/__init__.py

@@ -636,6 +636,12 @@ def test_config_loader(request):
     return config
 
 
+def test_config_loader_callable(request):
+    config = SPConfig()
+    config.load({'entityid': 'testentity_callable'})
+    return config
+
+
 def test_config_loader_with_real_conf(request):
     config = SPConfig()
     config.load(conf.create_conf(sp_host='sp.example.com',
@@ -653,6 +659,13 @@ def test_custom_conf_loader(self):
 
         self.assertEqual(conf.entityid, 'testentity')
 
+    def test_custom_conf_loader_callable(self):
+        config_loader_path = test_config_loader_callable
+        request = RequestFactory().get('/bar/foo')
+        conf = get_config(config_loader_path, request)
+
+        self.assertEqual(conf.entityid, 'testentity_callable')
+
     def test_custom_conf_loader_from_view(self):
         config_loader_path = 'djangosaml2.tests.test_config_loader_with_real_conf'
         request = RequestFactory().get('/login/')