push_notification: Add support to configure priority and push_type.

This commit adds support to let server configure:
* fcm_priority
* apns_priority
* apns_push_type

while sending E2EE push notifications.

The values of these fields will vary depending on whether the
send request is to send push notification for a message or
revoke an already sent notification.

Since, the bouncer receives encrypted data so it can't inspect
the payload to determine whether it is a removal request or not,
hence can't configure priority on its own.

The server needs to specify explicitly.

We're not simply sending a single 'is_removal' flag because
allowing the server to configure them separately will help in
future to support other types of notifications with a different
combination of priority and push_type, like whose aim is to notify
user about information other than a new message or removal request.

Fixes part of #35368.

zerver/lib/push_notifications.py

@@ -8,11 +8,11 @@ from collections.abc import Iterable, Mapping, Sequence
 from dataclasses import dataclass
 from email.headerregistry import Address
 from functools import cache
-from typing import TYPE_CHECKING, Any, Literal, Optional, TypeAlias, Union
+from typing import TYPE_CHECKING, Any, Final, Literal, Optional, TypeAlias, Union
 
 import lxml.html
 import orjson
-from aioapns.common import NotificationResult
+from aioapns.common import NotificationResult, PushType
 from django.conf import settings
 from django.db import transaction
 from django.db.models import F, Q
@@ -1451,18 +1451,33 @@ def send_push_notifications(
         assert push_device.bouncer_device_id is not None  # for mypy
         device_id_to_encrypted_data[str(push_device.bouncer_device_id)] = encrypted_data
 
+    # TODO: These literals will vary when implementing notification removal.
+    #
+    # Note: The "Final" qualifier serves as a shorthand
+    # for declaring that a variable is effectively Literal.
+    fcm_priority: Final = "high"
+    apns_priority: Final = 10
+    apns_push_type = PushType.ALERT
+
     # Send push notification
     try:
         if settings.ZILENCER_ENABLED:
             from zilencer.lib.push_notifications import send_e2ee_push_notifications
 
             response_data: SendNotificationResponseData = send_e2ee_push_notifications(
-                device_id_to_encrypted_data, realm=user_profile.realm
+                device_id_to_encrypted_data,
+                fcm_priority=fcm_priority,
+                apns_priority=apns_priority,
+                apns_push_type=apns_push_type,
+                realm=user_profile.realm,
             )
         else:
             post_data = {
                 "realm_uuid": str(user_profile.realm.uuid),
                 "device_id_to_encrypted_data": device_id_to_encrypted_data,
+                "fcm_priority": fcm_priority,
+                "apns_priority": apns_priority,
+                "apns_push_type": apns_push_type,
             }
             result = send_json_to_push_bouncer("POST", "push/e2ee/notify", post_data)
             assert isinstance(result["android_successfully_sent_count"], int)  # for mypy

zilencer/lib/push_notifications.py

@@ -1,8 +1,9 @@
 import asyncio
 import logging
 from collections.abc import Iterable
+from typing import Literal, TypeAlias
 
-from aioapns import NotificationRequest
+from aioapns import NotificationRequest, PushType
 from django.utils.timezone import now as timezone_now
 from firebase_admin import exceptions as firebase_exceptions
 from firebase_admin import messaging as firebase_messaging
@@ -19,6 +20,9 @@ from zilencer.models import RemotePushDevice, RemoteRealm
 
 logger = logging.getLogger(__name__)
 
+FCMPriority: TypeAlias = Literal["high", "normal"]
+APNsPriority: TypeAlias = Literal[10, 5, 1]
+
 
 def send_e2ee_push_notification_apple(
     apns_requests: list[NotificationRequest],
@@ -117,6 +121,9 @@ def send_e2ee_push_notification_android(
 def send_e2ee_push_notifications(
     device_id_to_encrypted_data: dict[str, str],
     *,
+    fcm_priority: FCMPriority,
+    apns_priority: APNsPriority,
+    apns_push_type: PushType,
     realm: Realm | None = None,
     remote_realm: RemoteRealm | None = None,
 ) -> SendNotificationResponseData:
@@ -147,18 +154,12 @@ def send_e2ee_push_notifications(
             "alert": {
                 "title": "New notification",
             },
-            # TODO: Should we remove `sound` and let the clients add it.
-            # Then we can rename it as `apns_required_message_payload`.
-            "sound": "default",
         },
     }
 
     fcm_requests = []
     fcm_remote_push_devices: list[RemotePushDevice] = []
 
-    # TODO: "normal" if remove event.
-    priority = "high"
-
     for remote_push_device in remote_push_devices:
         message_payload = {
             "encrypted_data": device_id_to_encrypted_data[str(remote_push_device.device_id)],
@@ -174,8 +175,8 @@ def send_e2ee_push_notifications(
                     apns_topic=remote_push_device.ios_app_id,
                     device_token=remote_push_device.token,
                     message=apns_message_payload,
-                    time_to_live=24 * 3600,
-                    # TODO: priority
+                    priority=apns_priority,
+                    push_type=apns_push_type,
                 )
             )
             apns_remote_push_devices.append(remote_push_device)
@@ -184,7 +185,7 @@ def send_e2ee_push_notifications(
                 firebase_messaging.Message(
                     data=message_payload,
                     token=remote_push_device.token,
-                    android=firebase_messaging.AndroidConfig(priority=priority),
+                    android=firebase_messaging.AndroidConfig(priority=fcm_priority),
                 )
             )
             fcm_remote_push_devices.append(remote_push_device)

zilencer/views.py

@@ -8,6 +8,7 @@ from uuid import UUID
 
 import orjson
 import requests.exceptions
+from aioapns import PushType
 from django.conf import settings
 from django.core.exceptions import ValidationError
 from django.core.validators import URLValidator, validate_email
@@ -92,7 +93,7 @@ from zilencer.auth import (
     generate_registration_transfer_verification_secret,
     validate_registration_transfer_verification_secret,
 )
-from zilencer.lib.push_notifications import send_e2ee_push_notifications
+from zilencer.lib.push_notifications import APNsPriority, FCMPriority, send_e2ee_push_notifications
 from zilencer.lib.remote_counts import MissingDataError
 from zilencer.models import (
     RemoteInstallationCount,
@@ -1807,6 +1808,9 @@ def remote_server_check_analytics(request: HttpRequest, server: RemoteZulipServe
 class SendE2EEPushNotificationPayload(BaseModel):
     realm_uuid: str
     device_id_to_encrypted_data: dict[str, str]
+    fcm_priority: FCMPriority
+    apns_priority: APNsPriority
+    apns_push_type: PushType
 
 
 @typed_endpoint
@@ -1844,7 +1848,11 @@ def remote_server_send_e2ee_push_notification(
     )
 
     response_data = send_e2ee_push_notifications(
-        device_id_to_encrypted_data, remote_realm=remote_realm
+        device_id_to_encrypted_data,
+        fcm_priority=payload.fcm_priority,
+        apns_priority=payload.apns_priority,
+        apns_push_type=payload.apns_push_type,
+        remote_realm=remote_realm,
     )
 
     do_increment_logging_stat(