How to use sails.io.js in Java

As we know sails.io.js is the Sails socket client that is bundled by default in new Sails apps. It is a lightweight wrapper that sits on top of the Socket.IO client whose purpose is to make sending and receiving messages from your Sails backend as simple as possible.

Currently sails.io.js has only support for Browser and Node.js. Here we will learn how to make .get(), .post(), .put(), .delete() and .request() methods from sails.io.js in Java with socket.io-client-java. For .off() and .on() there is no need since socket.io-client-java already does that.

Like surely you suspected emit method of socket.io-client-java is what we need to make sails.io.js request. Lets take a look to _emitFrom function from sails.io.js which is used to send requests.

function _emitFrom(socket, requestCtx) {

  ...

  // Since callback is embedded in requestCtx,
  // retrieve it and delete the key before continuing.
  var cb = requestCtx.cb;
  delete requestCtx.cb;

  // Name of the appropriate socket.io listener on the server
  // ( === the request method or "verb", e.g. 'get', 'post', 'put', etc. )
  var sailsEndpoint = requestCtx.method;

  socket._raw.emit(sailsEndpoint, requestCtx, function serverResponded(responseCtx) {

    // Send back (emulatedHTTPBody, jsonWebSocketResponse)
    if (cb) {
      cb(responseCtx.body, new JWR(responseCtx));
    }
  });
}

As you can see, sailsEndpoint is the HTTP method to use as the socket event. requestCtx is the body as the second argument of emit, and the third parameter passed to emit is the Acknowledge callback, a key parameter to receive response from server. Once serverResponded is executed, the callback extracted from requestCtx is called with response body and JSON web socket response.

For example, if we do a POST with body request, _emitFrom will be executed with the following requestCtx.

{
  method, 'POST',
  headers: { 'x-my-custom-header': 'some string' },
  data: { email: 'joshua.marquezn@gmail.com' },
  url: '/user'
  cb: function(responseBody, JWR) {
    // ...
  }
}

As we mentioned before

• method is the event
• headers, data and url is the second argument of .emit().
• cb is the Acknowledge callback of .emit().

Now lets try to do something similar but in Java.

This could be be our _emitFrom in Java.

void emitFrom(Socket socket, SailsSocketRequest request) {
  // Name of the appropriate socket.io listener on the server
  // ( === the request method or "verb", e.g. 'get', 'post', 'put', etc. )
  String sailsEndpoint = request.getMethod();

  // Since Listener is embedded in request, retrieve it.
  final SailsSocketResponse.Listener listener = request.getListener();

  socket.emit(sailsEndpoint, request.toJSONObject(), new Ack() {
    @Override
    public void call(Object... args) {
      // Send back jsonWebSocketResponse
      if (listener != null) {
        listener.onResponse(new JWR((JSONObject) args[0]));
      }
    }
  });
}

You can find a full implementation of sails.io.js in Java at https://github.com/joshuamarquez/sails.io.java.