request: Refactor to record rate limit data using ZulipRequestNotes.

We will no longer use the HttpRequest to store the rate limit data.
Using ZulipRequestNotes, we can access rate_limit and ratelimits_applied
with type hints support. We also save the process of initializing
ratelimits_applied by giving it a default value.

zerver/lib/rate_limiter.py

@@ -42,11 +42,12 @@ class RateLimitedObject(ABC):
         )
 
     def rate_limit_request(self, request: HttpRequest) -> None:
-        ratelimited, time = self.rate_limit()
+        from zerver.lib.request import get_request_notes
 
-        if not hasattr(request, "_ratelimits_applied"):
+        ratelimited, time = self.rate_limit()
-            request._ratelimits_applied = []
+        request_notes = get_request_notes(request)
-        request._ratelimits_applied.append(
+
+        request_notes.ratelimits_applied.append(
             RateLimitResult(
                 entity=self,
                 secs_to_freedom=time,
@@ -61,8 +62,8 @@ class RateLimitedObject(ABC):
 
         calls_remaining, seconds_until_reset = self.api_calls_left()
 
-        request._ratelimits_applied[-1].remaining = calls_remaining
+        request_notes.ratelimits_applied[-1].remaining = calls_remaining
-        request._ratelimits_applied[-1].secs_to_freedom = seconds_until_reset
+        request_notes.ratelimits_applied[-1].secs_to_freedom = seconds_until_reset
 
     def block_access(self, seconds: int) -> None:
         "Manually blocks an entity for the desired number of seconds"

zerver/middleware.py

@@ -544,8 +544,9 @@ class RateLimitMiddleware(MiddlewareMixin):
             return response
 
         # Add X-RateLimit-*** headers
-        if hasattr(request, "_ratelimits_applied"):
+        ratelimits_applied = get_request_notes(request).ratelimits_applied
-            self.set_response_headers(response, request._ratelimits_applied)
+        if len(ratelimits_applied) > 0:
+            self.set_response_headers(response, ratelimits_applied)
 
         return response
 

zerver/tornado/handlers.py

@@ -235,8 +235,8 @@ class AsyncDjangoHandler(tornado.web.RequestHandler, base.BaseHandler):
         # Add to this new HttpRequest logging data from the processing of
         # the original request; we will need these for logging.
         request_notes.log_data = old_request_notes.log_data
-        if hasattr(request, "_rate_limit"):
+        if request_notes.rate_limit is not None:
-            request._rate_limit = old_request._rate_limit
+            request_notes.rate_limit = old_request_notes.rate_limit
         if hasattr(request, "_requestor_for_logs"):
             request._requestor_for_logs = old_request._requestor_for_logs
         request.user = old_request.user

zproject/backends.py

@@ -70,7 +70,7 @@ from zerver.lib.email_validation import email_allowed_for_realm, validate_email_
 from zerver.lib.mobile_auth_otp import is_valid_otp
 from zerver.lib.rate_limiter import RateLimitedObject
 from zerver.lib.redis_utils import get_dict_from_redis, get_redis_client, put_dict_in_redis
-from zerver.lib.request import JsonableError
+from zerver.lib.request import JsonableError, get_request_notes
 from zerver.lib.subdomains import get_subdomain
 from zerver.lib.users import check_full_name, validate_user_custom_profile_field
 from zerver.models import (
@@ -259,12 +259,11 @@ def rate_limit_authentication_by_username(request: HttpRequest, username: str) -
 
 
 def auth_rate_limiting_already_applied(request: HttpRequest) -> bool:
-    if not hasattr(request, "_ratelimits_applied"):
+    request_notes = get_request_notes(request)
-        return False
 
     return any(
         isinstance(r.entity, RateLimitedAuthenticationByUsername)
-        for r in request._ratelimits_applied
+        for r in request_notes.ratelimits_applied
     )