Connect to Web Socket From Your Android App using OkHttp

Hello,

In this blog I am going to explain how you can connect with Web Socket from your Android App using OkHttp. This will be useful when you want to send some data real time from your Android app to Web app. 

First add following line in your build.gradle file dependencies. 

implementation 'com.squareup.okhttp3:okhttp:3.11.0'

Now let the gradle build and sync. Next we will make a class which extends WebSocketListener from OkHttp3 and a new class and name it MyWebSocketListener.java and add following code to it. 

import okhttp3.Response;

import okhttp3.WebSocket;

import okhttp3.WebSocketListener;

import okio.ByteString;

public final class MyWebSocketListener extends WebSocketListener {

    private static final int NORMAL_CLOSURE_STATUS = 5000;

    public MyWebSocketListener() {  

    }

    @Override

    public void onOpen(WebSocket webSocket, Response response) {

        webSocket.close(NORMAL_CLOSURE_STATUS, "Exit");

    }

    @Override

    public void onMessage(WebSocket webSocket, String text) {

        //String Meesage received

    }

    @Override

    public void onMessage(WebSocket webSocket, ByteString bytes) {

        //Meesage received in form of binary data

    }

    @Override

    public void onClosing(WebSocket webSocket, int code, String reason) {

        webSocket.close(NORMAL_CLOSURE_STATUS, null);

        //Closing socket

    }

    @Override

    public void onFailure(WebSocket webSocket, Throwable t, Response response) {

        t.printStackTrace();

    }

}

Now we have listener created. Let's create client and attach it to Web Socket and Listener.

val listener = MyWebSocketListener()

val webSocket =   OkHttpClient.Builder().build().newWebSocket(request, listener)

That's it, now you can use this instance to send or receive message.

Create Secure Web Socket (WSS) with Ratchet PHP

Hello,

Recently I was working on PHP project where we I was create secure web socket which is accessible with wss:// protocol. For this I struggled for couple of hours so here in blog I am going to explain how to do that so it can save your time. 

Earlier version was not supporting WSS but later it introduced React socket server which allows SSL connection. So here are steps you need to follow. 

First add all the required classed in your php file.

use Ratchet\Server\IoServer;

use Ratchet\Http\HttpServer;

use Ratchet\WebSocket\WsServer;

use MyApp\Socket;

In above example Socket is my class file which has all listeners. After this add auto load file.

require dirname( __FILE__ ) . '/vendor/autoload.php';

Next we will create our socket app. 

$app = new \Ratchet\Http\HttpServer(

    new \Ratchet\WebSocket\WsServer(

        new \MyApp\Socket()

    )

);

Now next step is to create React Secure server.

$loop = \React\EventLoop\Factory::create();

$webSock = new \React\Socket\Server('0.0.0.0:8080', $loop);

We are using 0.0.0.0  so this socket can be connected from anywhere. 

Now lets create secure server by adding path to certificate and key

$webSock = new \React\Socket\SecureServer($webSock, $loop, [

    'local_cert' => 'CRT_PATH', 

    'local_pk'=> 'KEY_PATH', 

    'allow_self_signed' => true, 

    'verify_peer' => false

]);

Now finally we will run our server.

$webSock = new \Ratchet\Server\IoServer($app, $webSock, $loop);

$webSock->run();

That's it. It will start your server to which you can connect with WSS protocol. To test you can use WebSocket ECHO test.

https://www.websocket.org/echo.html

Hope this helps you.

Socket.io Not Working on Android 9 (API 28)

Hi,

Recently in one of the project we faced a situation where we have used socket.io on backend and Android app connects to it. Socket.io was using http protocol for testing. It worked fine in older android versions but faced an issue in Android 9 and above where socket was connected but emit was not getting on server.

After couple of hours struggle finally found the problem. The problem was socket io was using http protocol and it's clearText HTTP request and it is banned in recent android version considering security reasons.

In earlier android version by default clearText is set as true but in later version default value is false. That means android components like HTTP and FTP and classes DownloadManager, and MediaPlayer can not use HTTP.

To over come this issue and allow socket to connect with HTTP protocol you have to allow clearText traffic on app level and for that you have to add following attribute in Application tag of your AndroidManifest.xml

<application
        android:usesCleartextTraffic="true">
.....
</application>

Once you add this to your manifest file, your socket emit will start working and you can still use HTTP with your socket.

Please note that since it was testing app we used HTTP based socket. However in production you should always use HTTPs protocol.

Hope this helps you.