Engine.IO-client Java

This is the Engine.IO Client Library for Java, which is simply ported from the JavaScript client.

See also: Socket.IO-client Java

Table of content

• Compatibility
• Installation
  • Maven
  • Gradle
• Usage
• Features
• License

Compatibility

Client version	Engine.IO server	Socket.IO server
0.9.x	1.x	1.x
1.x	3.x	2.x
2.x	4.x	3.x

Installation

The latest artifact is available on Maven Central.

Maven

Add the following dependency to your pom.xml.

<dependencies>
  <dependency>
    <groupId>io.socket</groupId>
    <artifactId>engine.io-client</artifactId>
    <version>2.1.0</version>
  </dependency>
</dependencies>

Gradle

Add it as a gradle dependency for Android Studio, in build.gradle:

compile ('io.socket:engine.io-client:2.1.0') {
  // excluding org.json which is provided by Android
  exclude group: 'org.json', module: 'json'
}

Usage

Engine.IO-client Java has the similar api with the JS client. You can use Socket to connect:

socket = new Socket("ws://localhost");
socket.on(Socket.EVENT_OPEN, new Emitter.Listener() {
  @Override
  public void call(Object... args) {
    socket.send("hi");
    socket.close();
  }
});
socket.open();

You can listen events as follows:

socket.on(Socket.EVENT_MESSAGE, new Emitter.Listener() {
  @Override
  public void call(Object... args) {
    String data = (String)args[0];
  }
}).on(Socket.EVENT_ERROR, new Emitter.Listener() {
  @Override
  public void call(Object... args) {
    Exception err = (Exception)args[0];
  }
});

How to set options:

opts = new Socket.Options();
opts.transports = new String[] {WebSocket.NAME};

socket = new Socket(opts);

Sending and receiving binary data:

socket = new Socket();
socket.on(Socket.EVENT_OPEN, new Emitter.Listener() {
  @Override
  public void call(Object... args) {
    // send binary data
    byte[] data = new byte[42];
    socket.send(data);
  }
}).on(Socket.EVENT_MESSAGE, new Emitter.Listener() {
  @Override
  public void call(Object... args) {
    // receive binary data
    byte[] data = (byte[])args[0];
  }
});

Use custom SSL settings:

OkHttpClient okHttpClient = new OkHttpClient.Builder()
    .hostnameVerifier(myHostnameVerifier)
    .sslSocketFactory(mySSLContext.getSocketFactory(), myX509TrustManager)
    .build();

// default SSLContext for all sockets
Socket.setDefaultOkHttpWebSocketFactory(okHttpClient);
Socket.setDefaultOkHttpCallFactory(okHttpClient);

// set as an option
opts = new Socket.Options();
opts.callFactory = okHttpClient;
opts.webSocketFactory = okHttpClient;
socket = new Socket(opts);

Features

This library supports all of the features the JS client does, including events, options and upgrading transport. Android is fully supported.

License

MIT