Merge pull request #288 from chunfengyao/master-ObserveNetworkChanges

feat: observe network changes

app/src/main/kotlin/com/github/gotify/service/WebSocketConnection.kt

@@ -116,13 +116,18 @@ internal class WebSocketConnection(
     @Synchronized
     fun close() {
         if (webSocket != null) {
+            webSocket?.close(1000, "")
+            closed()
             Log.i("WebSocket(${ID.get()}): closing existing connection.")
-            state = State.Disconnected
-            webSocket!!.close(1000, "")
-            webSocket = null
         }
     }
 
+    @Synchronized
+    private fun closed() {
+        webSocket = null
+        state = State.Disconnected
+    }
+
     @Synchronized
     fun scheduleReconnect(seconds: Long) {
         if (state == State.Connecting || state == State.Connected) {
@@ -150,7 +155,7 @@ internal class WebSocketConnection(
 
     private inner class Listener(private val id: Long) : WebSocketListener() {
         override fun onOpen(webSocket: WebSocket, response: Response) {
-            syncExec {
+            syncExec(id) {
                 state = State.Connected
                 Log.i("WebSocket($id): opened")
                 onOpen.run()
@@ -164,7 +169,7 @@ internal class WebSocketConnection(
         }
 
         override fun onMessage(webSocket: WebSocket, text: String) {
-            syncExec {
+            syncExec(id) {
                 Log.i("WebSocket($id): received message $text")
                 val message = Utils.JSON.fromJson(text, Message::class.java)
                 onMessageCallback(message)
@@ -173,12 +178,12 @@ internal class WebSocketConnection(
         }
 
         override fun onClosed(webSocket: WebSocket, code: Int, reason: String) {
-            syncExec {
+            syncExec(id) {
                 if (state == State.Connected) {
                     Log.w("WebSocket($id): closed")
                     onClose.run()
                 }
-                state = State.Disconnected
+                closed()
             }
             super.onClosed(webSocket, code, reason)
         }
@@ -187,11 +192,10 @@ internal class WebSocketConnection(
             val code = if (response != null) "StatusCode: ${response.code()}" else ""
             val message = if (response != null) response.message() else ""
             Log.e("WebSocket($id): failure $code Message: $message", t)
-            syncExec {
-                state = State.Disconnected
+            syncExec(id) {
+                closed()
                 if (response != null && response.code() >= 400 && response.code() <= 499) {
                     onBadRequest.execute(message)
-                    close()
                     return@syncExec
                 }
 
@@ -209,13 +213,12 @@ internal class WebSocketConnection(
             }
             super.onFailure(webSocket, t, response)
         }
+    }
 
-        private fun syncExec(runnable: Runnable) {
-            synchronized(this) {
+    @Synchronized
+    private fun syncExec(id: Long, runnable: () -> Unit) {
         if (ID.get() == id) {
-                    runnable.run()
-                }
-            }
+            runnable()
         }
     }
 

app/src/main/kotlin/com/github/gotify/service/WebSocketService.kt

@@ -5,9 +5,11 @@ import android.app.Notification
 import android.app.NotificationManager
 import android.app.PendingIntent
 import android.app.Service
+import android.content.Context
 import android.content.Intent
 import android.graphics.Color
 import android.net.ConnectivityManager
+import android.net.Network
 import android.net.Uri
 import android.os.Build
 import android.os.IBinder
@@ -43,6 +45,14 @@ internal class WebSocketService : Service() {
 
     private lateinit var settings: Settings
     private var connection: WebSocketConnection? = null
+    private val networkCallback: ConnectivityManager.NetworkCallback =
+        object : ConnectivityManager.NetworkCallback() {
+            override fun onAvailable(network: Network) {
+                super.onAvailable(network)
+                Log.i("WebSocket: Network available, reconnect if needed.")
+                connection?.start()
+            }
+        }
     private val appIdToApp = ConcurrentHashMap<Long, Application>()
 
     private val lastReceivedMessage = AtomicLong(NOT_LOADED)
@@ -67,9 +77,12 @@ internal class WebSocketService : Service() {
 
     override fun onDestroy() {
         super.onDestroy()
-        if (connection != null) {
-            connection!!.close()
+        connection?.close()
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            (getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager)
+                .unregisterNetworkCallback(networkCallback)
         }
+
         Log.w("Destroy ${javaClass.simpleName}")
     }
 
@@ -110,7 +123,9 @@ internal class WebSocketService : Service() {
             .onMessage { message -> onMessage(message) }
             .onReconnected { notifyMissedNotifications() }
             .start()
-
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            cm.registerDefaultNetworkCallback(networkCallback)
+        }
         fetchApps()
     }