rate_limiter: Store data in request._ratelimits_applied list.

The information used to be stored in a request._ratelimit dict, but
there's no need for that, and a list is a simpler structure, so this
allows us to simplify the plumbing somewhat.

zerver/lib/rate_limiter.py

@@ -41,14 +41,13 @@ class RateLimitedObject(ABC):
     def rate_limit_request(self, request: HttpRequest) -> None:
         ratelimited, time = self.rate_limit()
 
-        entity_type = type(self).__name__
-        if not hasattr(request, '_ratelimit'):
-            request._ratelimit = {}
-        request._ratelimit[entity_type] = RateLimitResult(
+        if not hasattr(request, '_ratelimits_applied'):
+            request._ratelimits_applied = []
+        request._ratelimits_applied.append(RateLimitResult(
             entity=self,
             secs_to_freedom=time,
             over_limit=ratelimited
-        )
+        ))
         # Abort this request if the user is over their rate limits
         if ratelimited:
             # Pass information about what kind of entity got limited in the exception:
@@ -56,8 +55,8 @@ class RateLimitedObject(ABC):
 
         calls_remaining, time_reset = self.api_calls_left()
 
-        request._ratelimit[entity_type].remaining = calls_remaining
-        request._ratelimit[entity_type].secs_to_freedom = time_reset
+        request._ratelimits_applied[-1].remaining = calls_remaining
+        request._ratelimits_applied[-1].secs_to_freedom = time_reset
 
     def block_access(self, seconds: int) -> None:
         "Manually blocks an entity for the desired number of seconds"

zerver/middleware.py

@@ -370,9 +370,8 @@ class RateLimitMiddleware(MiddlewareMixin):
             return response
 
         # Add X-RateLimit-*** headers
-        if hasattr(request, '_ratelimit'):
-            rate_limit_results = list(request._ratelimit.values())
-            self.set_response_headers(response, rate_limit_results)
+        if hasattr(request, '_ratelimits_applied'):
+            self.set_response_headers(response, request._ratelimits_applied)
 
         return response
 

zproject/backends.py

@@ -192,7 +192,11 @@ def rate_limit_authentication_by_username(request: HttpRequest, username: str) -
     RateLimitedAuthenticationByUsername(username).rate_limit_request(request)
 
 def auth_rate_limiting_already_applied(request: HttpRequest) -> bool:
-    return hasattr(request, '_ratelimit') and 'RateLimitedAuthenticationByUsername' in request._ratelimit
+    if not hasattr(request, '_ratelimits_applied'):
+        return False
+
+    return any(isinstance(r.entity, RateLimitedAuthenticationByUsername)
+               for r in request._ratelimits_applied)
 
 # Django's authentication mechanism uses introspection on the various authenticate() functions
 # defined by backends, so we need a decorator that doesn't break function signatures.