Java and Android Socketcluster Client
This SocketCluster Java/Android Client fork has the following differences from upstream:
- Jackson JSON parser is used, instead of JSON-java
- SocketCluster Minimal binary (sc-codec-min-bin) codec support. See Codecs section on usage example
- Underlying nv-websocket-client has been updated to the latest version
- Breaking: callback params now have Jackson
JsonNodetypes, instead of upstream'sObject
Important Note: Due to using jackson-databind this library is significantly bigger in size than upstream (~1.8 Mb), so if binary codec support is not needed, consider using upstream instead.
Overview
This client provides following functionality
- Support for emitting and listening to remote events
- Automatic reconnection
- Pub/sub
- Authentication (JWT)
- Binary codec support (
sc-codec-min-binincluded out-of-the-box)
License
Apache License, Version 2.0
Gradle
allprojects {
repositories {
jcenter()
maven { url "https://jitpack.io" }
}
}
...
dependencies {
implementation 'com.github.XDex:socketcluster-client-java:2.0.3'
}Description
Create instance of Socket class by passing url of socketcluster-server end-point
//Create a socket instance
String url="ws://localhost:8000/socketcluster/";
Socket socket = new Socket(url);
Important Note : Default url to socketcluster end-point is always ws://somedomainname.com/socketcluster/.
Registering basic listeners
Implemented using BasicListener interface
socket.setListener(new BasicListener() {
public void onConnected(Socket socket, Map<String, List<String>> headers) {
System.out.println("Connected to endpoint");
}
public void onDisconnected(Socket socket, WebSocketFrame serverCloseFrame, WebSocketFrame clientCloseFrame, boolean closedByServer) {
System.out.println("Disconnected from end-point");
}
public void onConnectError(Socket socket, WebSocketException exception) {
System.out.println("Got connect error "+ exception);
}
public void onSetAuthToken(String token, Socket socket) {
System.out.println("Token is "+ token);
}
public void onAuthentication(Socket socket, Boolean status) {
if (status) {
System.out.println("socket is authenticated");
} else {
System.out.println("Authentication is required (optional)");
}
}
});Connecting to server
- For connecting to server:
// This will send websocket handshake request to socketcluster-server
socket.connect();- For connecting asynchronously to server:
// This will send websocket handshake request to socketcluster-server
socket.connectAsync();- By default reconnection to server is not enabled, to enable it:
// This will set automatic reconnection to server with delay of 2 seconds and repeating it for 30 times
socket.setReconnection(new ReconnectStrategy().setDelay(2000).setMaxAttempts(30));
socket.connect();- To disable reconnection :
socket.setReconnection(null); - By default logging of messages is enabled, to disable:
socket.disableLogging();Emitting and listening to events
Event emitter
- eventname is name of event and message can be String, boolean, Long or JsonNode
socket.emit(eventname, message);
// socket.emit("chat", "Hi");- To send event with acknowledgement
socket.emit(eventname, message, new Ack() {
public void call(String eventName, JsonNode error, JsonNode data) {
System.out.println("Got message for :" + eventName + " error is: " + error + " data is:" + data);
}
});Event Listener
- For listening to events :
The object received can be String, Boolean, Long or JsonNode.
socket.on(eventname, new Emitter.Listener() {
public void call(String eventName, JsonNode data) {
System.out.println("Got message for: " + eventName + " data is: " + data);
}
}); - To send acknowledgement back to server
socket.on(eventname, new Emitter.AckListener() {
public void call(String eventName, JsonNode object, Ack ack) {
System.out.println("Got message: " + object);
// ...
if (error){
ack.call(eventName, error, null);
} else{
ack.call(eventName, null, data);
}
//Both error and data can be sent to server
ack.call(eventName, error, data);
}
});
Codecs
Custom binary SocketCluster codecs are supported.
Support for sc-codec-min-bin is included out-of-the-box.
To enable a binary codec, just set it as follows on the SocketCluster Socket:
socket.setCodec(new MinBinCodec());Custom binary codecs must implement the SocketClusterCodec interface.
Implementing Pub-Sub via channels
Creating channel
- For creating and subscribing to channels:
Socket.Channel channel = socket.createChannel(channelName);
// Socket.Channel channel = socket.createChannel("yolo");
/**
* without acknowledgement
*/
channel.subscribe();
/**
* with acknowledgement
*/
channel.subscribe(new Ack() {
public void call(String channelName, JsonNode error, JsonNode data) {
if (error == null) {
System.out.println("Subscribed to channel " + channelName + " successfully");
}
}
});- For getting list of created channels :
List <Socket.Channel> channels = socket.getChannels();- To get channel by name :
Socket.Channel channel = socket.getChannelByName("yolo");
//Returns null if channel of given name is not presentPublishing event on channel
- For publishing event :
// message can have any data type
/**
* without acknowledgement
*/
channel.publish(message);
/**
* with acknowledgement
*/
channel.publish(message, new Ack() {
public void call(String channelName, JsonNode error, JsonNode data) {
if (error == null) {
System.out.println("Published message to channel " + channelName + " successfully");
}
}
});
Listening to channel
- For listening to channel event :
channel.onMessage(new Emitter.Listener() {
public void call(String channelName , JsonNode object) {
System.out.println("Got message for channel " + channelName + " data is " + data);
}
});Unsubscribing a channel
/**
* without acknowledgement
*/
channel.unsubscribe();
/**
* with acknowledgement
*/
channel.unsubscribe(new Ack() {
public void call(String channelName, JsonNode error, JsonNode data) {
if (error == null) {
System.out.println("channel unsubscribed successfully");
}
}
}); Handling SSL connection with server
WebSocketFactory class is responsible for creating websocket instances and handling settings with server, for more
information visit here
To get instance of WebSocketFactory class :
WebSocketFactory factory = socket.getFactorySettings();
The following is an example to set a custom SSL context to a WebSocketFactory
instance. (Again, you don't have to call a setSSL* method if you use the default
SSL configuration.)
// Create a custom SSL context.
SSLContext context = NaiveSSLContext.getInstance("TLS");
// Set the custom SSL context.
factory.setSSLContext(context);NaiveSSLContext
used in the above example is a factory class to create an SSLContext which
naively accepts all certificates without verification. It's enough for testing
purposes. When you see an error message "unable to find valid certificate path
to requested target" while testing, try NaiveSSLContext.
Setting HTTP proxy with server
If a WebSocket endpoint needs to be accessed via an HTTP proxy, information
about the proxy server has to be set to a WebSocketFactory instance before
creating a WebSocket instance. Proxy settings are represented by
ProxySettings class. A WebSocketFactory instance has an associated
ProxySettings instance and it can be obtained by calling
WebSocketFactory.getProxySettings() method.
// Get the associated ProxySettings instance.
ProxySettings settings = factory.getProxySettings();ProxySettings class has methods to set information about a proxy server such
as setHost method and setPort method. The following is an example to set a
secure (https) proxy server.
// Set a proxy server.
settings.setServer("https://proxy.example.com");If credentials are required for authentication at a proxy server, setId
method and setPassword method, or setCredentials method can be used to set
the credentials. Note that, however, the current implementation supports only
Basic Authentication.
// Set credentials for authentication at a proxy server.
settings.setCredentials(id, password);