android - 需要 GCM 3.0 刷新注册 token 吗？

Question

使用最新的 GCM 更新 (3.0) 是否仍然需要在重启等情况下处理刷新注册 token ？ This article讨论了使 GCM 可靠，并涵盖了注册 token 可以更改的几种情况。在最新版本下这些步骤是必要的吗？在 IO 2015 的谈话中，他们说注册 token 是好的，直到从设备上卸载应用程序。

InstanceID instanceID = InstanceID.getInstance(this);
String token = instanceID.getToken(getString(R.string.gcm_defaultSenderId),
    GoogleCloudMessaging.INSTANCE_ID_SCOPE, null);

Answer 1

注册 token 重启后不应该刷新，但在其他情况下可能会刷新，所以你需要处理它。

使用更新后的 API，您需要实现 InstanceIDListenerService 来处理 token 刷新，如 google-services#android#gcm 中的示例。示例应用

    /**
     * Called if InstanceID token is updated. This may occur if the security of
     * the previous token had been compromised. This call is initiated by the
     * InstanceID provider.
     */
    // [START refresh_token]
    @Override
    public void onTokenRefresh() {
        // Fetch updated Instance ID token and notify our app's server of any changes (if applicable).
        Intent intent = new Intent(this, RegistrationIntentService.class);
        startService(intent);
    }

关于可能发生 token 刷新的其他情况。

• 查看https://developers.google.com/cloud-messaging/server-ref#error-codes, 未注册设备错误说明:

An existing registration token may cease to be valid in a number of scenarios, including:
- If the client app unregisters with GCM.
- If the client app is automatically unregistered, which can happen if the user uninstalls the application. For example, on iOS, if the APNS Feedback Service reported the APNS token as invalid.
- If the registration token expires (for example, Google might decide to refresh registration tokens, or the APNS token has expired for iOS devices).
- If the client app is updated but the new version is not configured to receive messages.

For all these cases, remove this registration token from the app server and stop using it to send messages.

• 根据 https://stackoverflow.com/a/16839326/313113 (截至 EDIT 04.24.2014)当用户升级应用程序并且您在升级发生的同时发送通知时似乎存在错误， token 被取消注册，因此您必须在应用程序升级后再次注册。 (不确定是否仍然如此)
• Token refreshes after backup/restore operation
• 位于 Keeping the Registration State in Sync 的文档出于安全原因，甚至建议定期从服务器刷新 token :

To protect the client app and app server from potential malicious re-use of registration tokens, you should periodically initiate token refresh from the server. When GCM registration token refresh is initiated from server side, the client app must handle a tokenRefreshed message with the GCM registration client/server handshake
See the API reference for more information on identity and token refresh procedure.