Added broadcast to discover server

Author: Samba89

.idea/misc.xml

@@ -0,0 +1,109 @@
+package uk.co.digitme.machinemonitoring.Helpers;
+
+import android.content.Context;
+import android.os.StrictMode;
+import android.util.Log;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.InterfaceAddress;
+import java.net.NetworkInterface;
+import java.net.SocketTimeoutException;
+import java.util.Enumeration;
+
+public class ServerDiscovery {
+
+    private static final int DISCOVERY_TIMEOUT_MS = 10000;
+    private static final String DISCOVERY_REQUEST_MESSAGE = "DISCOVER_OEE_SERVER_REQUEST";
+    private static final String DISCOVERY_RESPONSE_MESSAGE = "DISCOVER_OEE_SERVER_RESPONSE";
+    private static final String TAG = "ServerDiscovery";
+
+    public static boolean findServer(Context context) {
+        //Find the server using UDP broadcast
+        DbHelper dbHelper = new DbHelper(context);
+        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
+        StrictMode.setThreadPolicy(policy);
+        String ip;
+
+
+        try {
+            //Open a random port to send the package
+            DatagramSocket datagramSocket = new DatagramSocket();
+            datagramSocket.setBroadcast(true);
+            datagramSocket.setSoTimeout(DISCOVERY_TIMEOUT_MS);
+
+            byte[] sendData = DISCOVERY_REQUEST_MESSAGE.getBytes();
+
+            //Broadcast the message all over the network interfaces
+            Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
+            while (interfaces.hasMoreElements()) {
+                NetworkInterface networkInterface = interfaces.nextElement();
+
+                if (networkInterface.isLoopback() || !networkInterface.isUp()) {
+                    continue;   //Don't want to broadcast to the loopback interface
+                }
+
+                for (InterfaceAddress interfaceAddress : networkInterface.getInterfaceAddresses()) {
+                    InetAddress broadcast = interfaceAddress.getBroadcast();
+                    if (broadcast == null) {
+                        continue;
+                    }
+                    //Send the broadcast packet
+                    try {
+                        DatagramPacket sendPacket = new DatagramPacket(
+                                sendData,
+                                sendData.length,
+                                broadcast,
+                                8090);
+                        datagramSocket.send(sendPacket);
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                        return false;
+                    }
+                    Log.v(TAG,
+                            "Request packet sent to: " +
+                                    broadcast.getHostAddress() +
+                                    "; Interface: " +
+                                    networkInterface.getDisplayName());
+                }
+            }
+
+            Log.v(TAG, "Done looping over network interfaces. Waiting for a reply");
+
+            //Wait for a response
+            byte[] receiveBuf = new byte[15000];
+            DatagramPacket receivePacket = new DatagramPacket(receiveBuf, receiveBuf.length);
+            //Show a dialog if the connection times out
+            try {
+                datagramSocket.receive(receivePacket);
+            } catch (SocketTimeoutException e) {
+
+                Log.v(TAG, "Socket timeout. Exiting...");
+                datagramSocket.close();
+                return false;
+            }
+            //We have a response
+            Log.v(TAG, "Broadcast response from server: " + receivePacket.getAddress().getHostAddress());
+
+            //Check if the message is correct
+            String message = new String(receivePacket.getData()).trim();
+            if (message.equals(DISCOVERY_RESPONSE_MESSAGE)) {
+                ip = receivePacket.getAddress().toString();
+                Log.v(TAG, "HOST IP IS " + ip);
+                String address = "http://" + ip + ":80";  // todo support other ports
+                //Save the ip as a preference
+                dbHelper.saveServerAddress(address);
+                return true;
+            }
+
+            datagramSocket.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+            return false;
+        }
+        return false;
+
+    }
+}

app/src/main/java/uk/co/digitme/machinemonitoring/Helpers/ServerDiscovery.java

@@ -1,5 +1,7 @@
 package uk.co.digitme.machinemonitoring;
 
+import static uk.co.digitme.machinemonitoring.Helpers.ServerDiscovery.findServer;
+
 import android.annotation.SuppressLint;
 import android.content.Intent;
 import android.content.SharedPreferences;
@@ -84,8 +86,9 @@ public void onSingleClick(View v) {
     @Override
     protected void onResume() {
         super.onResume();
-        // On the first run, show the "set address" button immediately
+        // On the first run, try to get server address immediately
         if (prefs.getBoolean("firstrun", true)) {
+            discoverServer();
             mStatusText.setVisibility(View.INVISIBLE);
             mRetryButton.setVisibility(View.INVISIBLE);
             mSetAddressButton.setVisibility(View.VISIBLE);
@@ -101,11 +104,20 @@ protected void onResume() {
         }
     }
 
+
+    private boolean discoverServer(){
+        mStatusText.setText("Searching for OEE Server...");
+        return findServer(getApplicationContext());
+    }
+
+
     private void showError(String errorText) {
-        mStatusText.setText(errorText);
-        mStatusText.setVisibility(View.VISIBLE);
-        mRetryButton.setVisibility(View.VISIBLE);
-        mSetAddressButton.setVisibility(View.VISIBLE);
+        if (!discoverServer()) {
+            mStatusText.setText(errorText);
+            mStatusText.setVisibility(View.VISIBLE);
+            mRetryButton.setVisibility(View.VISIBLE);
+            mSetAddressButton.setVisibility(View.VISIBLE);
+        }
     }
 
     /**