Implement browser push notifications

backend/push_service.py

@@ -0,0 +1,149 @@
+import json
+import logging
+import os
+from typing import List, Optional
+from sqlalchemy.orm import Session
+from pywebpush import webpush, WebPushException
+from models import PushSubscription, User, Message, DMEnvelope
+
+logger = logging.getLogger("uvicorn.error")
+
+class PushNotificationService:
+    def __init__(self):
+        # VAPID keys - load from environment variables
+        self.vapid_private_key = os.getenv("VAPID_PRIVATE_KEY", "MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQghg2CSKiq0KsXXXImE75Z8UAphGBjkpYjUE87zPBmGqKhRANCAATxbNBGMhNl6gLmPL0PAf2YIJCVYX_TZrSqkj7SCqsu5VNMhnDOan6Qc9hEkcTZgvwj286C24SnxfH5CghVMCI6")
+        self.vapid_public_key = os.getenv("VAPID_PUBLIC_KEY", "BPFs0EYyE2XqAuY8vQ8B_ZggkJVhf9NmtKqSPtIKqy7lU0yGcM5qfpBz2ESRxNmC_CPbzoLbhKfF8fkKCFUwIjo")
+        self.vapid_claims = {
+            "sub": "mailto:admin@fromchat.com",
+            "aud": "https://fcm.googleapis.com"
+        }
+
+    async def subscribe_user(self, db: Session, user_id: int, endpoint: str, p256dh_key: str, auth_key: str) -> bool:
+        """Subscribe a user to push notifications"""
+        try:
+            # Check if user already has a subscription
+            existing_sub = db.query(PushSubscription).filter(PushSubscription.user_id == user_id).first()
+            
+            if existing_sub:
+                # Update existing subscription
+                existing_sub.endpoint = endpoint
+                existing_sub.p256dh_key = p256dh_key
+                existing_sub.auth_key = auth_key
+            else:
+                # Create new subscription
+                new_sub = PushSubscription(
+                    user_id=user_id,
+                    endpoint=endpoint,
+                    p256dh_key=p256dh_key,
+                    auth_key=auth_key
+                )
+                db.add(new_sub)
+            
+            db.commit()
+            logger.info(f"Push subscription saved for user {user_id}")
+            return True
+        except Exception as e:
+            logger.error(f"Failed to save push subscription for user {user_id}: {e}")
+            db.rollback()
+            return False
+
+    async def send_public_message_notification(self, db: Session, message: Message, exclude_user_id: Optional[int] = None):
+        """Send push notification for a new public chat message"""
+        try:
+            # Get all users except the sender
+            users = db.query(User).filter(User.id != message.user_id)
+            if exclude_user_id:
+                users = users.filter(User.id != exclude_user_id)
+            
+            for user in users:
+                # Check if user has push subscription before trying to send
+                subscription = db.query(PushSubscription).filter(PushSubscription.user_id == user.id).first()
+                if not subscription:
+                    continue
+                    
+                await self._send_notification_to_user(
+                    db, user.id, 
+                    f"New message from {message.author.username}",
+                    message.content[:100] + ("..." if len(message.content) > 100 else ""),
+                    message.author.profile_picture,
+                    {
+                        "type": "public_message",
+                        "message_id": message.id,
+                        "sender_id": message.user_id,
+                        "sender_username": message.author.username
+                    }
+                )
+        except Exception as e:
+            logger.error(f"Failed to send public message notifications: {e}")
+
+    async def send_dm_notification(self, db: Session, dm_envelope: DMEnvelope, sender: User):
+        """Send push notification for a new DM"""
+        try:
+            await self._send_notification_to_user(
+                db, dm_envelope.recipient_id,
+                f"New message from {sender.username}",
+                "You have a new direct message",
+                sender.profile_picture,
+                {
+                    "type": "dm",
+                    "dm_id": dm_envelope.id,
+                    "sender_id": sender.id,
+                    "sender_username": sender.username
+                }
+            )
+        except Exception as e:
+            logger.error(f"Failed to send DM notification: {e}")
+
+    async def _send_notification_to_user(self, db: Session, user_id: int, title: str, body: str, icon: Optional[str], data: dict):
+        """Send a push notification to a specific user"""
+        try:
+            subscription = db.query(PushSubscription).filter(PushSubscription.user_id == user_id).first()
+            if not subscription:
+                return
+
+            payload = {
+                "title": title,
+                "body": body,
+                "icon": icon or "/logo.png",
+                "tag": f"message_{user_id}",
+                "data": data
+            }
+
+            subscription_info = {
+                "endpoint": subscription.endpoint,
+                "keys": {
+                    "p256dh": subscription.p256dh_key,
+                    "auth": subscription.auth_key
+                }
+            }
+
+            webpush(
+                subscription_info=subscription_info,
+                data=json.dumps(payload),
+                vapid_private_key=self.vapid_private_key,
+                vapid_claims=self.vapid_claims
+            )
+            
+        except WebPushException as e:
+            logger.error(f"WebPush error for user {user_id}: {e}")
+            # If the subscription is invalid, remove it
+            if hasattr(e, 'response') and e.response and e.response.status_code in [410, 404]:
+                db.query(PushSubscription).filter(PushSubscription.user_id == user_id).delete()
+                db.commit()
+        except Exception as e:
+            logger.error(f"Failed to send push notification to user {user_id}: {e}")
+
+    async def unsubscribe_user(self, db: Session, user_id: int) -> bool:
+        """Unsubscribe a user from push notifications"""
+        try:
+            db.query(PushSubscription).filter(PushSubscription.user_id == user_id).delete()
+            db.commit()
+            logger.info(f"Push subscription removed for user {user_id}")
+            return True
+        except Exception as e:
+            logger.error(f"Failed to remove push subscription for user {user_id}: {e}")
+            db.rollback()
+            return False
+
+# Global instance
+push_service = PushNotificationService()