iOS设备推送通知令牌（Device Token）的App与服务端管理咨询

Hey there! Let's walk through how to handle Device Token management on both your iOS app and server, since you've already nailed the remote notification registration and token retrieval step—nice work!

App Side: Sending the Token to Your Server #

Let's tackle each of your questions one by one:

When should I send the token to the server? #

• First off, the application:didRegisterForRemoteNotificationsWithDeviceToken: callback is the first time you get a new token, but don't rush to send it immediately if your app requires user authentication. If your notifications are user-specific (like account alerts), you need to tie the token to a user ID—and you won't have that until the user logs in.
  • If your app supports notifications without login (e.g., a news app sending breaking stories), you can send the token right from this callback.
  • For authenticated apps: Store the token locally first (more on that below), then send it right after the user successfully logs in or switches accounts. Also, every time the callback fires (meaning the token has changed—this can happen on app reinstall, iOS update, or device swap), update your local storage and send the new token to the server as soon as you have a valid user session.

How often should I send it? #

You don't need to spam the server with token updates. Send it only when:

• A new token is generated (triggered by the registration callback)
• The user logs in for the first time after installing the app
• The user switches to a different account (to re-associate the token with the new user)
• You detect that the server doesn't have the current token (e.g., if a push notification failed and you get a feedback signal, though this is more server-side)

Should I send it with every login request? #

Not necessarily, but it's safe to do so if you build your server to handle it gracefully. If the user is logging into the same account and the server already has their token, your server can just ignore the duplicate or update the record without creating a new entry. The key here is making your server's token endpoint idempotent—so repeated requests don't cause issues.

Send directly from the callback, or store first then send? #

Store first, then send when you have a valid user context is the more reliable approach:

• Store the token securely using Keychain (better than UserDefaults, since it persists across app updates and is encrypted; UserDefaults gets wiped if the app is uninstalled).
• When the registration callback fires, update your Keychain with the new token.
• Then, whenever the user logs in (or if they're already logged in when the callback fires), grab the token from Keychain and send it to the server.
• This avoids sending a token without a user ID, which is useless for targeted notifications.

Server Side: Handling the Token Once Received #

Once your server gets the token, here's what you need to do:

• Associate it with a user ID: If your app uses authentication, link the token to the corresponding user account. This lets you send targeted notifications to specific users.
• Store tokens efficiently: Use a database table that maps user IDs to their device tokens (support multiple tokens per user—one user might have multiple iOS devices).
• Handle duplicates: Check if the token already exists for the user before storing it. If it does, skip adding a new entry or update the existing one (e.g., refresh the last updated timestamp).
• Track token validity: APNs will return error codes (like InvalidToken) when a token is no longer valid (e.g., user uninstalled the app). When you get this feedback, mark the token as invalid in your database and stop sending notifications to it. You can also run periodic cleanup jobs to remove invalid tokens.
• Use HTTPS: Always transmit tokens over HTTPS to prevent interception.
• Support idempotency: Make sure your token submission endpoint doesn't create duplicate records if the app sends the same token multiple times.

内容的提问来源于stack exchange，提问作者Alexis Darnat