Add member count API for public chat

.cursor/rules/no-placeholder-string-sanitization.mdc

@@ -0,0 +1,10 @@
+---
+description: Do not filter cache, API, or DB fields by matching fixed UI/placeholder English strings
+alwaysApply: true
+---
+
+# No magic-string “sanitization” of user or message data
+
+- **Never** strip, null out, or rewrite stored or displayed values by comparing them to hard-coded UI strings (e.g. `"Direct messages"`, `"Direct message"`, `"User 123"`, etc.). Those strings can be legitimate **usernames, display names, or message text**.
+- **Prefer**: fix the source (don’t persist placeholders; use `null`/absent fields; fix the writer). If legacy bad rows exist, use an explicit **schema/version/migration** or a **documented sentinel** agreed with the backend—not substring or equality checks on natural language.
+- Applies especially to: local storage/cache layers, list previews, and any code that “cleans” strings before show or read.

backend/services/main/routes/account.py

@@ -1,7 +1,7 @@
 from datetime import datetime
 from collections import defaultdict, deque
 import time
-from fastapi import APIRouter, Depends, HTTPException, status, Request
+from fastapi import APIRouter, BackgroundTasks, Depends, HTTPException, status, Request
 from sqlalchemy.orm import Session
 from sqlalchemy import inspect, text
 import uuid
@@ -25,6 +25,17 @@ _FAILED_ATTEMPT_THRESHOLD = 5
 _failed_login_attempts: dict[str, deque[float]] = defaultdict(deque)
 
 
+async def _broadcast_registered_user_count_task():
+    from ..db import SessionLocal
+    from .messaging import messagingManager
+
+    db = SessionLocal()
+    try:
+        await messagingManager.broadcast_registered_user_count(db)
+    finally:
+        db.close()
+
+
 def _record_failed_login(identifier: str) -> bool:
     now = time.time()
     attempts = _failed_login_attempts[identifier]
@@ -173,7 +184,12 @@ def login(request: Request, login_request: LoginRequest, db: Session = Depends(g
 
 @router.post("/register")
 @rate_limit_per_ip("3/hour")
-def register(request: Request, register_request: RegisterRequest, db: Session = Depends(get_db)):
+def register(
+    request: Request,
+    register_request: RegisterRequest,
+    background_tasks: BackgroundTasks,
+    db: Session = Depends(get_db),
+):
     username = register_request.username.strip()
     display_name = register_request.display_name.strip()
     password = register_request.password.strip()
@@ -288,6 +304,8 @@ def register(request: Request, register_request: RegisterRequest, db: Session =
         owner=is_owner,
     )
 
+    background_tasks.add_task(_broadcast_registered_user_count_task)
+
     return {
         "status": "success",
         "message": "Регистрация прошла успешно",
@@ -550,6 +568,12 @@ async def _delete_user_data(user: User, db: Session):
         # Log error but don't fail the request
         pass
 
+    try:
+        from .messaging import messagingManager
+        await messagingManager.broadcast_registered_user_count(db)
+    except Exception:
+        pass
+
 
 @router.post("/delete")
 async def delete_account(
@@ -564,7 +588,7 @@ async def delete_account(
         raise HTTPException(status_code=400, detail="Cannot delete admin/owner account")
     
     await _delete_user_data(current_user, db)
-    
+
     log_security(
         "self_delete_account",
         severity="warning",

backend/services/main/routes/messaging.py

@@ -1045,6 +1045,8 @@ class MessaggingSocketManager:
         elif update_type == "statusUpdate":
             # Deduplicate by user ID
             sig_data = {"type": update_type, "userId": data.get("userId")}
+        elif update_type == "registeredUserCount":
+            sig_data = {"type": update_type, "count": data.get("count")}
         else:
             # For unknown types, use full data (less efficient but safe)
             sig_data = {"type": update_type, "data": data}
@@ -1297,6 +1299,17 @@ class MessaggingSocketManager:
             if websocket in self.user_by_ws:
                 await self._send_update(websocket, message_type, update_data, db)
 
+    async def broadcast_registered_user_count(self, db: Session):
+        """Notify all clients of the current non-deleted user count (public chat member count)."""
+        try:
+            n = db.query(User).filter(User.deleted.is_(False)).count()
+        except Exception:
+            return
+        try:
+            await self.broadcast({"type": "registeredUserCount", "data": {"count": n}}, db)
+        except Exception:
+            pass
+
     async def send_update_to_user(self, user_id: int, update_type: str, update_data: dict, db: Session | None = None):
         """Send an update to a specific user (batched)"""
         for websocket in self.connections:

backend/services/main/routes/profile.py

@@ -276,6 +276,16 @@ async def update_user_bio(
     }
 
 
+@router.get("/user/stats/registered-count")
+def get_registered_user_count(
+    current_user: User = Depends(get_current_user),
+    db: Session = Depends(get_db),
+):
+    """Number of registered accounts (non-deleted users)."""
+    n = db.query(User).filter(User.deleted.is_(False)).count()
+    return {"count": n}
+
+
 @router.get("/user/{username}")
 async def get_user_by_username(
     username: str,