From 74c50b953557ea283a6cd601ad3656379369eb47 Mon Sep 17 00:00:00 2001
From: Tom Christie <tom@tomchristie.com>
Date: Thu, 6 Sep 2012 15:42:54 +0100
Subject: [PATCH] Settings suppport importpaths

---
 djangorestframework/request.py  | 25 ++++++++--
 djangorestframework/settings.py | 86 +++++++++++++++++++++++++++------
 2 files changed, 90 insertions(+), 21 deletions(-)

diff --git a/djangorestframework/request.py b/djangorestframework/request.py
index cddb14157..6c00ff621 100644
--- a/djangorestframework/request.py
+++ b/djangorestframework/request.py
@@ -11,9 +11,8 @@ The wrapped request then offers a richer API, in particular :
 """
 from StringIO import StringIO
 
-from django.contrib.auth.models import AnonymousUser
-
 from djangorestframework import exceptions
+from djangorestframework.settings import api_settings
 from djangorestframework.utils.mediatypes import is_form_media_type
 
 
@@ -251,10 +250,26 @@ class Request(object):
         return self._not_authenticated()
 
     def _not_authenticated(self):
-        return (AnonymousUser(), None)
+        """
+        Return a two-tuple of (user, authtoken), representing an
+        unauthenticated request.
 
-    def __getattr__(self, name):
+        By default this will be (AnonymousUser, None).
+        """
+        if api_settings.UNAUTHENTICATED_USER:
+            user = api_settings.UNAUTHENTICATED_USER()
+        else:
+            user = None
+
+        if api_settings.UNAUTHENTICATED_TOKEN:
+            auth = api_settings.UNAUTHENTICATED_TOKEN()
+        else:
+            auth = None
+
+        return (user, auth)
+
+    def __getattr__(self, attr):
         """
         Proxy other attributes to the underlying HttpRequest object.
         """
-        return getattr(self._request, name)
+        return getattr(self._request, attr)
diff --git a/djangorestframework/settings.py b/djangorestframework/settings.py
index e801a9f1c..f25133d52 100644
--- a/djangorestframework/settings.py
+++ b/djangorestframework/settings.py
@@ -15,35 +15,89 @@ API_SETTINGS = {
 
 """
 from django.conf import settings
-from djangorestframework import renderers
+from django.utils import importlib
 from djangorestframework.compat import yaml
 
 
 DEFAULTS = {
     'DEFAULT_RENDERERS': (
-        renderers.JSONRenderer,
-        renderers.JSONPRenderer,
-        # renderers.DocumentingHTMLRenderer,
-        # renderers.DocumentingXHTMLRenderer,
-        renderers.DocumentingPlainTextRenderer,
-        # renderers.XMLRenderer
-    )
+        'djangorestframework.renderers.JSONRenderer',
+        'djangorestframework.renderers.JSONPRenderer',
+        'djangorestframework.renderers.DocumentingPlainTextRenderer',
+    ),
+    'DEFAULT_PARSERS': (
+        'djangorestframework.parsers.JSONParser',
+        'djangorestframework.parsers.FormParser'
+    ),
+    'UNAUTHENTICATED_USER': 'django.contrib.auth.models.AnonymousUser',
+    'UNAUTHENTICATED_TOKEN': None
 }
 
 if yaml:
-    DEFAULTS['DEFAULT_RENDERERS'] += (renderers.YAMLRenderer, )
+    DEFAULTS['DEFAULT_RENDERERS'] += ('djangorestframework.renderers.YAMLRenderer', )
+
+
+# List of settings that may be in string import notation.
+IMPORT_STRINGS = (
+    'DEFAULT_RENDERERS',
+    'UNAUTHENTICATED_USER',
+    'UNAUTHENTICATED_TOKEN'
+)
+
+
+def perform_import(val, setting):
+    """
+    If the given setting is a string import notation,
+    then perform the necessary import or imports.
+    """
+    if val is None or setting not in IMPORT_STRINGS:
+        return val
+
+    try:
+        if isinstance(val, basestring):
+            return import_from_string(val)
+        elif isinstance(val, (list, tuple)):
+            return [import_from_string(item) for item in val]
+        return val
+    except:
+        msg = "Could not import '%s' for API setting '%s'" % (val, setting)
+        raise ImportError(msg)
+
+
+def import_from_string(val):
+    """
+    Attempt to import a class from a string representation.
+    """
+    # Nod to tastypie's use of importlib.
+    parts = val.split('.')
+    module_path, class_name = '.'.join(parts[:-1]), parts[-1]
+    module = importlib.import_module(module_path)
+    return getattr(module, class_name)
 
 
 class APISettings(object):
+    """
+    A settings object, that allows API settings to be accessed as properties.
+    For example:
+
+        from djangorestframework.settings import api_settings
+        print api_settings.DEFAULT_RENDERERS
+
+    Any setting with string import paths will be resolved.
+    """
     def __getattr__(self, attr):
+        if attr not in DEFAULTS.keys():
+            raise AttributeError("Invalid API setting: '%s'" % attr)
+
         try:
-            return settings.API_SETTINGS[attr]
+            # Check if present in user settings
+            val = perform_import(settings.API_SETTINGS[attr], attr)
         except (AttributeError, KeyError):
-            # 'API_SETTINGS' does not exist,
-            # or requested setting is not present in 'API_SETTINGS'.
-            try:
-                return DEFAULTS[attr]
-            except KeyError:
-                raise AttributeError("No such setting '%s'" % attr)
+            # Fall back to defaults
+            val = perform_import(DEFAULTS[attr], attr)
+
+        # Cache the result
+        setattr(self, attr, val)
+        return val
 
 api_settings = APISettings()