无需修改第三方App代码实现Android/iOS推送技术方案问询

Hi Axel, great question—this is a common scenario when working with third-party apps you don't control, and the solution depends heavily on platform-specific rules and the assets you can get from the app owner. Let's break this down step by step:

First, let's cover the non-negotiable requirements to even attempt this:

• Platform-level push credentials: For Android, you'll need the target app's FCM Server Key; for iOS, an APNs Certificate or Auth Key tied to the app's Bundle ID.
• Device push tokens: The FCM Token (Android) or APNs Device Token (iOS) for each user's device you want to target.
• Formal authorization from the app owner: This isn't just a nicety—using someone else's app credentials violates Google/Apple developer terms and privacy laws like GDPR without explicit permission.

If the Target App Uses FCM #

This is the easiest path. Since the app already has the FCM SDK integrated, you can leverage Firebase's APIs directly:

1. Grab the target app's FCM Server Key from their Firebase Console (under Project Settings → Cloud Messaging).
2. Send push requests via FCM's HTTP API. Here's a quick curl example:

curl -X POST "https://fcm.googleapis.com/fcm/send" \
     -H "Authorization: key=YOUR_TARGET_APP_FCM_KEY" \
     -H "Content-Type: application/json" \
     -d '{
           "to": "USER_FCM_TOKEN",
           "notification": {
             "title": "Your Alert Title",
             "body": "Your push message content"
           }
         }'

• Important: You can't customize how the push behaves (e.g., opening a specific screen, playing a custom sound) because that's controlled by the app's existing FCM code—you're just triggering the app's pre-configured push handling.

If the Target App Doesn't Use FCM #

Unfortunately, you can't send pushes to Android apps that haven't integrated any push SDK. Android has no native push mechanism that works without app-side code. The only exception is if the app uses another vendor-specific push service (like Xiaomi/Huawei Push), but you'd need that service's credentials for the target app—and the app must already be integrated with it.

iOS is simpler here because all push notifications go through Apple's APNs, regardless of whether the app uses a third-party SDK (like Firebase Cloud Messaging for iOS, which just forwards to APNs). As long as you have:

• The target app's APNs Certificate (or Auth Key) from Apple Developer Portal
• The user's APNs Device Token
• A matching Bundle ID between the certificate/key and the app

You can send pushes directly via APNs' HTTP/2 API. Example curl request:

curl -X POST "https://api.push.apple.com/3/device/USER_APNS_TOKEN" \
     -H "apns-topic: com.target.app.bundleid" \
     -H "authorization: bearer YOUR_APNS_AUTH_TOKEN" \
     -H "Content-Type: application/json" \
     -d '{
           "aps": {
             "alert": {
               "title": "Your Alert Title",
               "body": "Your push message content"
             },
             "sound": "default"
           }
         }'

• Note: iOS pushes are subject to Apple's rules—users must have granted push permissions, and if the app is uninstalled, the Device Token will stop working. Again, you can't customize the app's response to the push without modifying its code.

Let's clarify when to use each:

Using Firebase #

• Best for: Target apps that already use FCM (Android), or if you want a single interface to send pushes to both Android and iOS (Firebase handles forwarding iOS pushes to APNs).
• Pros: You don't have to manage APNs certificate rotations or token validation manually—Firebase handles that.
• Cons: Useless for Android apps without FCM; you still need to configure APNs credentials in Firebase for iOS.

Direct Integration (Your Own Notification Server) #

• Best for: You want full control over push logic, or the target iOS app doesn't use Firebase.
• Pros: No dependency on Firebase; you can fine-tune APNs/FCM requests to your needs.
• Cons: You'll have to handle certificate/key management, token expiration, and platform-specific error handling yourself.

Here's the tough truth: you can't get read receipts or user interaction data without modifying the target app.

• Platform services (FCM/APNs) only return whether the push was successfully delivered to the device (e.g., token invalid, device offline). They don't track if the user opened or read the push.
• To get read receipts, the app would need to send a request to your server when the user interacts with the push—and that requires changing the app's code, which you can't do.
• The only indirect feedback you might get is token invalidation (which could mean the app was uninstalled), but that's not a reliable signal for read status.

Don't skip this:

• Always get written authorization from the app owner to use their push credentials and device data. Violating Google/Apple's terms can lead to permanent bans from their developer programs.
• Follow privacy laws like GDPR and CCPA: Ensure users have opted in to receive pushes, and provide a way for them to opt out.

内容的提问来源于stack exchange，提问作者Axel