loopback-socket

Loopback module for create Socket.io connections and allow call methods.

Installation

npm install loopback-socket --save

Usage

Server side

Include

const LoopbackSocket = require('loopback-socket');

LoopbackSocket.get(name, [timeout])

Create or get a instance with a specific name.

Arguments

Name	Type	Description
name	string	Name to instance. Required
[timeout]	integer	Time to wait authentication after establish connection before disconnect the socket. Optional.

Example

const loopbackSocket = LoopbackSocket.get('name');
const loopbackSocket = LoopbackSocket.get('name', 2000);

loopbackSocket.start(io)

Configure authentication, callbacks and methods with a server socket.

Arguments

Name	Type	Description
io	object	Server Socket IO instance. Required.

Example

const server = require('http').createServer();
const io = require('socket.io')(server);
loopbackSocket.start(io);

loopbackSocket.auth(authentication)

Set the function to authenticate connected sockets.

Arguments

Name	Type	Description
authentication	autentication function or object	Function called with (socket, credentials, [cb]) arguments or object like { model: Model, method: methodName } where Model is a class and methodName is one of its methods (defined or to be defined) like autentication function.

Authentication function

If an error is thrown in this function or it return a false value then authentication fails. If argument cb is not defined then the returned value will be a the authentication response, and if this value is a promise, then it will be resolved before.

Name	Type	Description
socket	object	Socket connected. Required.
credentials	object	Credentials received. Required.
[cb]	function	Callback with (err, success) arguments to async return value with NodeJs callback style. Optional.

Example

// Authentication function with NodeJs callback style
function customAuthentication(socket, credentials, cb) {
  User.getUserByCredentials(credentials, cb);
}

// Authentication function with direct value returned o Promise style
function customAuthentication(socket, credentials) {
  return User.getUserByCredentials(credentials); // return data or a promise
}

// Direct setting
loopbackSocket.auth(customAuthentication);

// Setting through a Model
function MyModel() {};

loopbackSocket.auth({
  model: MyModel,
  method: 'customAuthentication'
});

MyModel.customAuthentication = authentication;

loopbackSocket.onConnected(handler)

Add a on connected handler.

Arguments

Name	Type	Description
handler	handler function or object	Function called with (socket, credentials, [cb]) arguments or object like { model: Model, method: methodName } where Model is a class and methodName is one of its methods (defined or to be defined) with like handler function.

Handler function

If argument cb is not defined then the returned value will be a the handler response, and if this value is a promise, then it will be resolved before.

Name	Type	Description
socket	object	Socket connected. Required.
credentials	object	Credentials received. Required.
[cb]	function	Callback with (err, success) arguments to async return value with NodeJs callback style. Optional.

Example

// Authentication function with NodeJs callback style
function customOnConnectedHandler(socket, credentials, cb) {
  User.getUserByCredentials(credentials, cb);
}

// Authentication function with direct value returned o Promise style
function customOnConnectedHandler(socket, credentials) {
  return User.getUserByCredentials(credentials); // return data or a promise
}

// Direct adding
loopbackSocket.onConnected(customOnConnectedHandler);

// Adding through a Model
function MyModel() {};

loopbackSocket.onConnected({
  model: MyModel,
  method: 'customOnConnectedHandler'
});

MyModel.customOnConnectedHandler = customOnConnectedHandler;

loopbackSocket.removeOnConnected(handler)

Remove a connected handler

Arguments

Name	Type	Description
handler	function or object	Function called with (socket, credentials, [cb]) arguments or object like { model: Model, method: methodName } where Model is a class and methodName is one of its methods (defined or to be defined) with like handler function.

Example

// Direct remove
loopbackSocket.onConnected(customOnConnectedHandler);

// Remove Model method
function MyModel() {};

loopbackSocket.removeOnConnected({
  model: MyModel,
  method: 'customOnConnectedHandler'
});

loopbackSocket.defineMethod(methodName, method)

Define a method to call by socket connection or replace one existing.

Arguments

Name	Type	Description
methodName	string	Method name.
method	method function or object	Function called with (socket, credentials, args, [cb]) arguments or object like { model: Model, method: methodName } where Model is a class and methodName is one of its methods (defined or to be defined) with like method function.

Method function

If argument cb is not defined then the returned value will be the method called reponse, and if this value is a promise, then it will be resolved before.

Name	Type	Description
socket	object	Socket connected. Required.
credentials	object	Credentials received. Required.
args.	object	Arguments to call method. Required.
[cb]	function	Callback with (err, success) arguments to async return value with NodeJs callback style. Optional.

Example

/// Method function with NodeJs callback style
function customMethod(socket, credentials, args, cb) {
  let data;

  // Option 1
  cb(null, data); // Client receives { result: data }
  
  // Option 2
  cb('myError');  // Client receives { error: 'myError' }

}

/// Method function with direct value returned o Promise style
function customMethod(socket, credentials, args) {
  let dataOrPromise;

  // Option 1
  return dataOrPromise; // Client receives { result: dataOrPromiseResolvedValue }

  // Option 2
  throw 'myError'; // Client receives { error: 'myError' }

}

// Direct definition
loopbackSocket.defineMethod('customMethod', customMethod);


// Definition through a Model
function MyModel() {};

loopbackSocket.defineMethod('customMethod', {
  model: MyModel,
  method: 'customMethod',
});

MyModel.customMethod = customMethod;

loopbackSocket.removeMethod(methodName)

Remove a method of socket.

Arguments

Name	Type	Description
methodName	string	Method name to remove.

Example

// Direct remove
loopbackSocket.onConnected('customMethod');

Client side sample

const socket = io('http://localhost');

socket.on('connect', (socket) => {
  // send credentials
  socket.emit('authentication', credentials);
});

socket.on('authenticated', (socket) => {
  // socket authenticated
});

socket.on('unauthorized', (socket) => {
  // socket failed authentication
});

function callMyMethod() {
  // Call a defined socket method
  socket.emit('myMethod', {}, (response) => {
    if (response.error) {
      // Method return a error;
      return;
    }
    // Method success;
    console.log(response.result);
  });
}

Samples

Loopback + AngularJS:

https://github.com/arondn2/loopback-socket/tree/master/examples/loopback

Troubles

If you have any kind of trouble with it, just let me now by raising an issue on the GitHub issue tracker here:

https://github.com/arondn2/loopback-socket/issues

Also, you can report the orthographic errors in the READMEs files or comments. Sorry for that, I do not speak English.

Tests

npm test or npm run cover

Contributing

In lieu of a formal style guide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code.