@tomasperezv/multi-websocket

MultiWebsocket

This library provides a way to architect webservices that can be routed through the same websocket connection and accessed from the client-side transparently.

Initially the client will perform a XMLHttpRequest to a discovery service that will be in charge of returning a mapping that will define how to access to the different webservices and the address of the websocket gateway.

Once the service discovery is completed a websocket gateway is stablished and subsequent requests through the MultiWebsocket.Client object will be routed automatically.

MultiWebsocket.Client exposes an interface based on Promise in order to ease code readability and maintainability.

Example

An example project is located at the example folder:

First the example project must be setup:

cd ./example
npm install

The previous instruction will install the required dependencies, after that you must run the server:

npm run start-server

The example server is implemented via Silex.js a custom node.js framework for developing RESTFUL webservices that can be exposed via websockets or HTTP that I've implemented.

This example server will be in charge of implementing the server side methods 'helloworld' and 'autocomplete' as well as 'discover'.

'discover' it's an internal method that it's used by the MultiWebsocket client side in order to resolve and route requests to the different endpoints.

Then you can run the client

npm run start-client

The client will be built via Webpack and will listen on http://localhost:9999/index.html, you can visit this URL to see the project in action.

Every second 2 requests via the Websocket Gateway will be performed.

How to write a client

For writing a client you must extend the MultiWebsocket's Client object and define its configuration and different available methods:

const methods = {
  HELLO_WORLD: '/helloworld/'
};

const ExampleClient = function() {
  /**
   * @type {Object} config
   */
  this.config = {
    'service-discovery-url': 'http://localhost:7007/discover/'
  };

  MultiWebsocket.Client.call(this);
};

ExampleClient.prototype = Object.create(MultiWebsocket.Client.prototype);

/**
 * @method helloWorld
 * @return {Promise}
 * @public
*/
ExampleClient.prototype.helloWorld = function() {
  return this.callService(methods.HELLO_WORLD, {});
};

Now we need to connect to the Websocket's Gateway by using the connect method:

ExampleClient.connect();

After calling to connect we can't perform requests right away cause the connection to the Webocket Gateway is asynchronous, but we can be notified once the connection is ready via the onReady method:

client.onReady(() => {
  client.helloWorld()
    .then((data) => { console.log(data); });
});

In the previous snippet, after the onReady event is triggered, we call to our custom webservice through the Websocket and use the Promise returned to read the message from the server as a JSON object.