java 中的 XMPP 服务器未收到来自 GCM 服务器的所有消息

Question

我已经使用 Smack 库实现了 XMPP 服务器，我的服务器从 Google 云消息服务器（现在是 Firebase）获取消息，但问题是当我从 [=19 一条一条地发送消息时=] 到 gcm 服务器，我的 XMPP 服务器只收到第一条消息，第二条被拦截，（我只能看到有一条消息的通知

<message id="gQaM0-6"><gcm xmlns="google:mobile:data">{"message_type":"ack","message_id":"0","to":"eVtypIWW7Q8:APA91bH5oU0AC3zyuCAWVYkMzoGQeIiGe71c2BL4lE5uFHRfB3iPXtD-qIJDmJZ3ySsPDi0VhkKl0Cz3XZG7rWa1Ca7pX9yQqzWSMXBiGK4SEO4Q-Owfr45E_VBJMrXqsSziuJhek"}</gcm></message>

但我没有这方面的数据我在方法 void processPacket(Packet packet) 中得到的第一条消息这是 XMPP 服务器的完整代码：

public class XMPPServer implements PacketListener {

    private static XMPPServer sInstance = null;
    private XMPPConnection connection;
    private ConnectionConfiguration config;
    private String mApiKey = null;
    private String mProjectId = null;
    private boolean mDebuggable = false;
    private String fcmServerUsername = null;

    public static XMPPServer getInstance() {
        if (sInstance == null) {
            throw new IllegalStateException("You have to prepare the client first");
        }
        return sInstance;
    }

    public static XMPPServer prepareClient(String projectId, String apiKey, boolean debuggable) {
        synchronized (XMPPServer.class) {
            if (sInstance == null) {
                sInstance = new XMPPServer(projectId, apiKey, debuggable);
            }
        }
        return sInstance;
    }

    private XMPPServer(String projectId, String apiKey, boolean debuggable) {
        this();
        mApiKey = apiKey;
        mProjectId = projectId;
        mDebuggable = debuggable;
        fcmServerUsername = mProjectId + "@" + Util.FCM_SERVER_CONNECTION;
    }

    private XMPPServer() {
        // Add GcmPacketExtension
        ProviderManager.getInstance().addExtensionProvider(Util.FCM_ELEMENT_NAME, Util.FCM_NAMESPACE,
                new PacketExtensionProvider() {

                    @Override
                    public PacketExtension parseExtension(XmlPullParser parser) throws Exception {
                        String json = parser.nextText();
                        GcmPacketExtension packet = new GcmPacketExtension(json);
                        return packet;
                    }
                });
    }

    /**
     * Connects to FCM Cloud Connection Server using the supplied credentials
     */
    public void connect() throws XMPPException {
        config = new ConnectionConfiguration(Util.FCM_SERVER, Util.FCM_PORT);
        config.setSecurityMode(SecurityMode.enabled);
        config.setReconnectionAllowed(true);
        config.setSocketFactory(SSLSocketFactory.getDefault());
        // Launch a window with info about packets sent and received
        config.setDebuggerEnabled(mDebuggable);

        connection = new XMPPConnection(config);
        connection.connect();

        connection.addConnectionListener(new ConnectionListener() {
                //a few overrided methods
        });
        // Handle incoming packets (the class implements the PacketListener)
        connection.addPacketListener(this, new PacketTypeFilter(Message.class));

        // Second message without data I get in this method (1)
        connection.addPacketWriterInterceptor(new PacketInterceptor() {
            @Override
            public void interceptPacket(Packet packet) {
                System.out.println("INTERCEPT PACKAGE: " + packet.toXML());
            }
        }, new PacketTypeFilter(Message.class));
        connection.login(fcmServerUsername, mApiKey);
    }
    /**
     * Normal message with my data I get in this method (2)
     */
    @SuppressWarnings("unchecked")
    @Override
    public void processPacket(Packet packet) {
        Message incomingMessage = (Message) packet;
        GcmPacketExtension gcmPacket = (GcmPacketExtension) incomingMessage.getExtension(Util.FCM_NAMESPACE);
        String json = gcmPacket.getJson();
        System.out.println("Message : " + json);
     }

差不多全代码了，最重要的部分我用（1）和（2）标出来了，（用搜索快速找到）为什么我的数据只能收到第一条消息？为什么第二条消息会转到 PacketInterceptor（标记 (1) ）？

Answer 1

如果您使用的是 Firebase Cloud Messaging(FCM)，请检查您的应用服务器是否连接到以下端点：

// Production
fcm-xmpp.googleapis.com:5235

// Testing
fcm-xmpp.googleapis.com:5236

除此之外，您可能还想检查 Downstream messages 其中提到一旦 XMPP 连接建立，CCS 和您的服务器使用正常的 XMPP <message> 节发送 JSON-来回编码的消息。 <message> 的正文必须是：

<gcm xmlns:google:mobile:data>
    JSON payload
</gcm>

此外，请注意 JSON 常规 FCM 消息有效负载中的例外情况。访问给定的链接以获取更多信息。

这些相关的 SO 帖子也可能有帮助：

Send FCM messages from server side to android device

java 中的 XMPP 服务器未收到来自 GCM 服务器的所有消息

XMPP server in java does not receive all messages from GCM server

java

android

google-cloud-messaging

xmpp

smack