Added rest framework

thirdpart/rest_framework/throttling.py

@@ -0,0 +1,208 @@
+import time
+from django.core.cache import cache
+from rest_framework import exceptions
+from rest_framework.settings import api_settings
+
+
+class BaseThrottle(object):
+    """
+    Rate throttling of requests.
+    """
+    def allow_request(self, request, view):
+        """
+        Return `True` if the request should be allowed, `False` otherwise.
+        """
+        raise NotImplementedError('.allow_request() must be overridden')
+
+    def wait(self):
+        """
+        Optionally, return a recommended number of seconds to wait before
+        the next request.
+        """
+        return None
+
+
+class SimpleRateThrottle(BaseThrottle):
+    """
+    A simple cache implementation, that only requires `.get_cache_key()`
+    to be overridden.
+
+    The rate (requests / seconds) is set by a :attr:`throttle` attribute
+    on the :class:`.View` class.  The attribute is a string of the form 'number of
+    requests/period'.
+
+    Period should be one of: ('s', 'sec', 'm', 'min', 'h', 'hour', 'd', 'day')
+
+    Previous request information used for throttling is stored in the cache.
+    """
+
+    timer = time.time
+    settings = api_settings
+    cache_format = 'throtte_%(scope)s_%(ident)s'
+    scope = None
+
+    def __init__(self):
+        if not getattr(self, 'rate', None):
+            self.rate = self.get_rate()
+        self.num_requests, self.duration = self.parse_rate(self.rate)
+
+    def get_cache_key(self, request, view):
+        """
+        Should return a unique cache-key which can be used for throttling.
+        Must be overridden.
+
+        May return `None` if the request should not be throttled.
+        """
+        raise NotImplementedError('.get_cache_key() must be overridden')
+
+    def get_rate(self):
+        """
+        Determine the string representation of the allowed request rate.
+        """
+        if not getattr(self, 'scope', None):
+            msg = ("You must set either `.scope` or `.rate` for '%s' throttle" %
+                   self.__class__.__name__)
+            raise exceptions.ConfigurationError(msg)
+
+        try:
+            return self.settings.DEFAULT_THROTTLE_RATES[self.scope]
+        except KeyError:
+            msg = "No default throttle rate set for '%s' scope" % self.scope
+            raise exceptions.ConfigurationError(msg)
+
+    def parse_rate(self, rate):
+        """
+        Given the request rate string, return a two tuple of:
+        <allowed number of requests>, <period of time in seconds>
+        """
+        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]]
+        return (num_requests, duration)
+
+    def allow_request(self, request, view):
+        """
+        Implement the check to see if the request should be throttled.
+
+        On success calls `throttle_success`.
+        On failure calls `throttle_failure`.
+        """
+        if self.rate is None:
+            return True
+
+        self.key = self.get_cache_key(request, view)
+        self.history = cache.get(self.key, [])
+        self.now = self.timer()
+
+        # Drop any requests from the history which have now passed the
+        # throttle duration
+        while self.history and self.history[-1] <= self.now - self.duration:
+            self.history.pop()
+        if len(self.history) >= self.num_requests:
+            return self.throttle_failure()
+        return self.throttle_success()
+
+    def throttle_success(self):
+        """
+        Inserts the current request's timestamp along with the key
+        into the cache.
+        """
+        self.history.insert(0, self.now)
+        cache.set(self.key, self.history, self.duration)
+        return True
+
+    def throttle_failure(self):
+        """
+        Called when a request to the API has failed due to throttling.
+        """
+        return False
+
+    def wait(self):
+        """
+        Returns the recommended next request time in seconds.
+        """
+        if self.history:
+            remaining_duration = self.duration - (self.now - self.history[-1])
+        else:
+            remaining_duration = self.duration
+
+        available_requests = self.num_requests - len(self.history) + 1
+
+        return remaining_duration / float(available_requests)
+
+
+class AnonRateThrottle(SimpleRateThrottle):
+    """
+    Limits the rate of API calls that may be made by a anonymous users.
+
+    The IP address of the request will be used as the unique cache key.
+    """
+    scope = 'anon'
+
+    def get_cache_key(self, request, view):
+        if request.user.is_authenticated():
+            return None  # Only throttle unauthenticated requests.
+
+        ident = request.META.get('REMOTE_ADDR', None)
+
+        return self.cache_format % {
+            'scope': self.scope,
+            'ident': ident
+        }
+
+
+class UserRateThrottle(SimpleRateThrottle):
+    """
+    Limits the rate of API calls that may be made by a given user.
+
+    The user id will be used as a unique cache key if the user is
+    authenticated.  For anonymous requests, the IP address of the request will
+    be used.
+    """
+    scope = 'user'
+
+    def get_cache_key(self, request, view):
+        if request.user.is_authenticated():
+            ident = request.user.id
+        else:
+            ident = request.META.get('REMOTE_ADDR', None)
+
+        return self.cache_format % {
+            'scope': self.scope,
+            'ident': ident
+        }
+
+
+class ScopedRateThrottle(SimpleRateThrottle):
+    """
+    Limits the rate of API calls by different amounts for various parts of
+    the API.  Any view that has the `throttle_scope` property set will be
+    throttled.  The unique cache key will be generated by concatenating the
+    user id of the request, and the scope of the view being accessed.
+    """
+    scope_attr = 'throttle_scope'
+
+    def get_cache_key(self, request, view):
+        """
+        If `view.throttle_scope` is not set, don't apply this throttle.
+
+        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,
+            'ident': ident
+        }