⚡ Bolt: [performance improvement] Pre-serialized JSON caching for utility endpoints

backend/routers/utility.py

@@ -1,9 +1,9 @@
-from fastapi import APIRouter, Depends, HTTPException, Query
-from fastapi.responses import JSONResponse
+from fastapi import APIRouter, Depends, HTTPException, Query, Response
 from sqlalchemy.orm import Session
 from sqlalchemy import func, case
 from datetime import datetime, timezone
 import logging
+import json
 
 from backend.database import get_db
 from backend.models import Issue
@@ -51,7 +51,7 @@ def health():
 def get_stats(db: Session = Depends(get_db)):
     cached_stats = recent_issues_cache.get("stats")
     if cached_stats:
-        return JSONResponse(content=cached_stats)
+        return Response(content=cached_stats, media_type="application/json")
 
     # Optimized: Single aggregate query for both category breakdowns and system-wide totals
     # This eliminates a redundant database roundtrip
@@ -84,9 +84,10 @@ def get_stats(db: Session = Depends(get_db)):
     )
 
     data = response.model_dump(mode='json')
-    recent_issues_cache.set(data, "stats")
+    json_data = json.dumps(data)
+    recent_issues_cache.set(json_data, "stats")
 
-    return response
+    return Response(content=json_data, media_type="application/json")
 
 @router.get("/ml-status", response_model=MLStatusResponse)
 async def ml_status():
@@ -116,7 +117,7 @@ def get_leaderboard(db: Session = Depends(get_db)):
     cache_key = "leaderboard"
     cached_data = recent_issues_cache.get(cache_key)
     if cached_data:
-        return JSONResponse(content=cached_data)
+        return Response(content=cached_data, media_type="application/json")
 
     # Group by user_email, count issues, sum upvotes
     # Optimization: Only select needed columns and use aggregation
@@ -149,10 +150,11 @@ def get_leaderboard(db: Session = Depends(get_db)):
         ).model_dump(mode='json'))
 
     response_data = {"leaderboard": leaderboard_data}
+    json_data = json.dumps(response_data)
     # Cache for 5 minutes to reduce DB load on frequent hits
-    recent_issues_cache.set(response_data, cache_key)
+    recent_issues_cache.set(json_data, cache_key)
 
-    return response_data
+    return Response(content=json_data, media_type="application/json")
 
 
 @router.get("/mh/rep-contacts")

backend/tests/benchmark_serialization.py

@@ -0,0 +1,26 @@
+import time
+import json
+from fastapi import Response
+from fastapi.responses import JSONResponse
+
+data = {"leaderboard": [{"user_email": "abc@def.com", "reports_count": 10, "total_upvotes": 50, "rank": 1} for _ in range(100)]}
+json_data = json.dumps(data)
+
+def test_jsonresponse():
+    start = time.perf_counter()
+    for _ in range(10000):
+        # JSONResponse internally calls json.dumps
+        resp = JSONResponse(content=data)
+        _ = resp.body
+    return time.perf_counter() - start
+
+def test_rawresponse():
+    start = time.perf_counter()
+    for _ in range(10000):
+        resp = Response(content=json_data, media_type="application/json")
+        _ = resp.body
+    return time.perf_counter() - start
+
+if __name__ == "__main__":
+    print(f"JSONResponse: {test_jsonresponse():.4f}s")
+    print(f"Response with pre-serialized JSON: {test_rawresponse():.4f}s")