Additional throttle rate configurability

docs/api-guide/throttling.md

@@ -41,7 +41,7 @@ The default throttling policy may be set globally, using the `DEFAULT_THROTTLE_C
         }
     }
 
-The rate descriptions used in `DEFAULT_THROTTLE_RATES` may include `second`, `minute`, `hour` or `day` as the throttle period.
+The rate descriptions used in `DEFAULT_THROTTLE_RATES` may include `second`, `minute`, `hour` or `day` as the throttle period. To set the rate to a fraction of a period, simply prepend the desired timespan. For example, a rate of `'100/30s'` will mean "limit requests to a maximum of 100 per every 30 seconds".
 
 You can also set the throttling policy on a per-view or per-viewset basis,
 using the `APIView` class-based views.

rest_framework/throttling.py

@@ -1,6 +1,7 @@
 """
 Provides various throttling policies.
 """
+import re
 import time
 
 from django.core.cache import cache as default_cache
@@ -101,9 +102,26 @@ class SimpleRateThrottle(BaseThrottle):
         """
         if rate is None:
             return (None, None)
-        num, period = rate.split('/')
-        num_requests = int(num)
-        duration = {'s': 1, 'm': 60, 'h': 3600, 'd': 86400}[period[0]]
+
+        try:
+            num, period = rate.split('/')
+            num_requests = int(num)
+            # Get rate multiplier value if available
+            period_mult, _ = re.split('[s|m|h|d]', period, maxsplit=1)
+            period_char = re.findall('[s|m|h|d]', period)[0]
+        except ValueError:
+            msg = "Incorrect throttle rate set for '%s' scope" % self.scope
+            raise ImproperlyConfigured(msg)
+
+        try:
+            period_mult = int(period_mult)
+        except ValueError:
+            period_mult = 1
+
+        duration = {'s': 1 * period_mult,
+                    'm': 60 * period_mult,
+                    'h': 3600 * period_mult,
+                    'd': 86400 * period_mult}[period_char]
         return (num_requests, duration)
 
     def allow_request(self, request, view):

tests/test_throttling.py

@@ -451,6 +451,9 @@ class SimpleRateThrottleTests(TestCase):
     def setUp(self):
         SimpleRateThrottle.scope = 'anon'
 
+    def tearDown(self):
+        SimpleRateThrottle.rate = None
+
     def test_get_rate_raises_error_if_scope_is_missing(self):
         throttle = SimpleRateThrottle()
         with pytest.raises(ImproperlyConfigured):
@@ -462,6 +465,48 @@ class SimpleRateThrottleTests(TestCase):
         with pytest.raises(ImproperlyConfigured):
             SimpleRateThrottle()
 
+    def test_throttle_raises_error_if_rate_is_incorrect(self):
+        SimpleRateThrottle.rate = 'rate'
+        with pytest.raises(ImproperlyConfigured):
+            SimpleRateThrottle()
+
+        SimpleRateThrottle.rate = 'rate/hour'
+        with pytest.raises(ImproperlyConfigured):
+            SimpleRateThrottle()
+
+        SimpleRateThrottle.rate = '100/century'
+        with pytest.raises(ImproperlyConfigured):
+            SimpleRateThrottle()
+
+        SimpleRateThrottle.rate = '100/10century'
+        with pytest.raises(ImproperlyConfigured):
+            SimpleRateThrottle()
+
+    def test_parse_rate_returns_correct_rate(self):
+        rate_str = '10/h'
+        SimpleRateThrottle.rate = rate_str
+        rate = SimpleRateThrottle().parse_rate(rate_str)
+        assert rate == (10, 3600)
+
+        rate_str = '30/hour'
+        SimpleRateThrottle.rate = rate_str
+        rate = SimpleRateThrottle().parse_rate(rate_str)
+        assert rate == (30, 3600)
+
+        rate_str = '30/10min'
+        SimpleRateThrottle.rate = rate_str
+        rate = SimpleRateThrottle().parse_rate(rate_str)
+        assert rate == (30, 10 * 60)
+
+        rate_str = '100/30seconds'
+        SimpleRateThrottle.rate = rate_str
+        rate = SimpleRateThrottle().parse_rate(rate_str)
+        assert rate == (100, 30)
+
+        SimpleRateThrottle.rate = '100/10d'
+        rate = SimpleRateThrottle().parse_rate('100/10d')
+        assert rate == (100, 10 * 86400)
+
     def test_parse_rate_returns_tuple_with_none_if_rate_not_provided(self):
         rate = SimpleRateThrottle().parse_rate(None)
         assert rate == (None, None)