1 files changed, 27 insertions, 12 deletions

diff --git a/rest_framework/throttling.py b/rest_framework/throttling.py
index 93ea9816..f6bb1cc8 100644
--- a/rest_framework/throttling.py
+++ b/rest_framework/throttling.py
@@ -3,7 +3,7 @@ Provides various throttling policies.
 """
 from __future__ import unicode_literals
 from django.core.cache import cache
-from rest_framework import exceptions
+from django.core.exceptions import ImproperlyConfigured
 from rest_framework.settings import api_settings
 import time
 
@@ -40,9 +40,9 @@ class SimpleRateThrottle(BaseThrottle):
     """
 
     timer = time.time
-    settings = api_settings
     cache_format = 'throtte_%(scope)s_%(ident)s'
     scope = None
+    THROTTLE_RATES = api_settings.DEFAULT_THROTTLE_RATES
 
     def __init__(self):
         if not getattr(self, 'rate', None):
@@ -65,13 +65,13 @@ class SimpleRateThrottle(BaseThrottle):
         if not getattr(self, 'scope', None):
             msg = ("You must set either `.scope` or `.rate` for '%s' throttle" %
                    self.__class__.__name__)
-            raise exceptions.ConfigurationError(msg)
+            raise ImproperlyConfigured(msg)
 
         try:
-            return self.settings.DEFAULT_THROTTLE_RATES[self.scope]
+            return self.THROTTLE_RATES[self.scope]
         except KeyError:
             msg = "No default throttle rate set for '%s' scope" % self.scope
-            raise exceptions.ConfigurationError(msg)
+            raise ImproperlyConfigured(msg)
 
     def parse_rate(self, rate):
         """
@@ -187,6 +187,27 @@ class ScopedRateThrottle(SimpleRateThrottle):
     """
     scope_attr = 'throttle_scope'
 
+    def __init__(self):
+        # Override the usual SimpleRateThrottle, because we can't determine
+        # the rate until called by the view.
+        pass
+
+    def allow_request(self, request, view):
+        # We can only determine the scope once we're called by the view.
+        self.scope = getattr(view, self.scope_attr, None)
+
+        # If a view does not have a `throttle_scope` always allow the request
+        if not self.scope:
+            return True
+
+        # Determine the allowed request rate as we normally would during
+        # the `__init__` call.
+        self.rate = self.get_rate()
+        self.num_requests, self.duration = self.parse_rate(self.rate)
+
+        # We can now proceed as normal.
+        return super(ScopedRateThrottle, self).allow_request(request, view)
+
     def get_cache_key(self, request, view):
         """
         If `view.throttle_scope` is not set, don't apply this throttle.
@@ -194,18 +215,12 @@ class ScopedRateThrottle(SimpleRateThrottle):
         Otherwise generate the unique cache key by concatenating the user id
         with the '.throttle_scope` property of the view.
         """
-        scope = getattr(view, self.scope_attr, None)
-
-        if not scope:
-            # Only throttle views if `.throttle_scope` is set on the view.
-            return None
-
         if request.user.is_authenticated():
             ident = request.user.id
         else:
             ident = request.META.get('REMOTE_ADDR', None)
 
         return self.cache_format % {
-            'scope': scope,
+            'scope': self.scope,
             'ident': ident
         }