ios - 我们是否应该在应用程序启动期间每次都注册 iOS 推送通知？

Question

我们在我们的 iOS 应用程序中使用远程通知，我们在 application: didFinishLaunching: 委托(delegate)方法中注册到 APNS 服务器。这意味着每次应用程序重新启动时，它都会在 APNS 服务器上注册。下面是代码片段。

[[UIApplication sharedApplication] registerForRemoteNotifications]

我们注意到设备 token (由 APNS 服务器发送给我们)每次都是相同的。 因此，我们认为我们可以将 token 保存在 NSUserDefaults 中以备后用。在 application: didFinishLaunching: 方法中，我们可以检查设备 token 是否存在于 NSUserDefaults 中。如果它可用，我们可以使用它而不是注册到 APNS。否则，我们可以选择注册 APNS。

但是，从 Apple 文档中可以看出，“他们鼓励我们在每次新启动应用程序时注册远程通知”。以下是文档的屏幕截图。

设备 token 值实际何时更改？我可以负担得起将设备 token 存储在 NSUserDefaults 中并在以后使用它而不是每次都注册吗？请帮忙!!提前致谢!!

Answer 1

用一些苹果文档回答你的问题:

The form of this phase of token trust ensures that only APNs generates the token which it will later honor, and it can assure itself that a token handed to it by a device is the same token that it previously provisioned for that particular device—and only for that device.

If the user restores backup data to a new device or reinstalls the operating system, the device token changes.

这意味着您不应该真正将 token 存储在您的 NSUserDefaults 中。

但是，如果您无论如何都想保存它，我建议将其保存在钥匙串(keychain)中。 请参阅此示例如何执行此操作: Store Device Token in Keychain

苹果文档中的另一段引述:

"By requesting the device token and passing it to the provider every time your application launches, you help to ensure that the provider has the current token for the device. If a user restores a backup to a device other than the one that the backup was created for (for example, the user migrates data to a new device), he or she must launch the application at least once for it to receive notifications again. If the user restores backup data to a new device or reinstalls the operating system, the device token changes. Moreover, never cache a device token and give that to your provider; always get the token from the system whenever you need it. If your application has previously registered, calling registerForRemoteNotificationTypes: results in iOS passing the device token to the delegate immediately without incurring additional overhead."

编辑: 看起来上面指向 Apple 文档的链接现在已损坏。这是一个更新的链接(感谢@Enrico Cupellini):https://developer.apple.com/library/content/technotes/tn2265/_index.html