Wait for network when websocket connection failed

app/src/main/java/com/github/gotify/service/ReconnectListener.java

@@ -0,0 +1,30 @@
+package com.github.gotify.service;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.net.ConnectivityManager;
+import android.net.NetworkInfo;
+import com.github.gotify.log.Log;
+
+public class ReconnectListener extends BroadcastReceiver {
+
+    private Runnable reconnected;
+
+    ReconnectListener(Runnable reconnected) {
+        this.reconnected = reconnected;
+    }
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        ConnectivityManager cm =
+                (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
+
+        NetworkInfo network = cm.getActiveNetworkInfo();
+
+        if (network != null && network.isConnected()) {
+            Log.i("Network reconnected");
+            reconnected.run();
+        }
+    }
+}

app/src/main/java/com/github/gotify/service/WebSocketConnection.java

@@ -1,5 +1,7 @@
 package com.github.gotify.service;
 
+import android.net.ConnectivityManager;
+import android.net.NetworkInfo;
 import android.os.Handler;
 import com.github.gotify.SSLSettings;
 import com.github.gotify.Utils;
@@ -16,6 +18,7 @@ import okhttp3.WebSocket;
 import okhttp3.WebSocketListener;
 
 public class WebSocketConnection {
+    private final ConnectivityManager connectivityManager;
     private OkHttpClient client;
 
     private final Handler handler = new Handler();
@@ -31,8 +34,14 @@ public class WebSocketConnection {
     private OnFailureCallback onFailure;
     private Runnable onReconnected;
     private boolean isClosed;
+    private Runnable onDisconnect;
 
-    WebSocketConnection(String baseUrl, SSLSettings settings, String token) {
+    WebSocketConnection(
+            String baseUrl,
+            SSLSettings settings,
+            String token,
+            ConnectivityManager connectivityManager) {
+        this.connectivityManager = connectivityManager;
         OkHttpClient.Builder builder =
                 new OkHttpClient.Builder()
                         .readTimeout(0, TimeUnit.MILLISECONDS)
@@ -66,6 +75,11 @@ public class WebSocketConnection {
         return this;
     }
 
+    synchronized WebSocketConnection onDisconnect(Runnable onDisconnect) {
+        this.onDisconnect = onDisconnect;
+        return this;
+    }
+
     synchronized WebSocketConnection onFailure(OnFailureCallback onFailure) {
         this.onFailure = onFailure;
         return this;
@@ -153,6 +167,13 @@ public class WebSocketConnection {
                     return;
                 }
 
+                NetworkInfo network = connectivityManager.getActiveNetworkInfo();
+                if (network == null || !network.isConnected()) {
+                    Log.i("WebSocket: Network not connected");
+                    onDisconnect.run();
+                    return;
+                }
+
                 int minutes = Math.min(errorCount * 2 + 1, 20);
 
                 Log.i("WebSocket: trying to restart in " + minutes + " minute(s)");

app/src/main/java/com/github/gotify/service/WebSocketService.java

@@ -6,8 +6,11 @@ import android.app.PendingIntent;
 import android.app.Service;
 import android.content.Context;
 import android.content.Intent;
+import android.content.IntentFilter;
 import android.graphics.Color;
+import android.net.ConnectivityManager;
 import android.os.Build;
+import android.os.Handler;
 import android.os.IBinder;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
@@ -25,6 +28,7 @@ import com.github.gotify.log.Log;
 import com.github.gotify.log.UncaughtExceptionHandler;
 import com.github.gotify.messages.MessagesActivity;
 import java.util.List;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 
 public class WebSocketService extends Service {
@@ -84,15 +88,45 @@ public class WebSocketService extends Service {
             missingMessageUtil.lastReceivedMessage(lastReceivedMessage::set);
         }
 
+        ConnectivityManager cm =
+                (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
+
         connection =
-                new WebSocketConnection(settings.url(), settings.sslSettings(), settings.token())
+                new WebSocketConnection(
+                                settings.url(), settings.sslSettings(), settings.token(), cm)
                         .onOpen(this::onOpen)
                         .onClose(() -> foreground(getString(R.string.websocket_closed)))
                         .onBadRequest(this::onBadRequest)
                         .onFailure((min) -> foreground(getString(R.string.websocket_failed, min)))
+                        .onDisconnect(this::onDisconnect)
                         .onMessage(this::onMessage)
                         .onReconnected(this::notifyMissedNotifications)
                         .start();
+
+        IntentFilter intentFilter = new IntentFilter();
+        intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
+        ReconnectListener receiver = new ReconnectListener(this::doReconnect);
+        registerReceiver(receiver, intentFilter);
+    }
+
+    private void onDisconnect() {
+        foreground(getString(R.string.websocket_no_network));
+    }
+
+    private void doReconnect() {
+        if (connection == null) {
+            return;
+        }
+
+        new Handler()
+                .postDelayed(
+                        () -> new Thread(this::notifyAndStart).start(),
+                        TimeUnit.SECONDS.toMillis(5));
+    }
+
+    private void notifyAndStart() {
+        notifyMissedNotifications();
+        connection.start();
     }
 
     private void onBadRequest(String message) {

app/src/main/res/values/strings.xml

@@ -57,4 +57,5 @@
     <string name="warning">Warning</string>
     <string name="http_warning">Using http is insecure and it\'s recommend to use https instead. Use your favorite search engine to get more information about this topic.</string>
     <string name="i_understand">I Understand</string>
+    <string name="websocket_no_network">Waiting for network</string>
 </resources>