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# Socket.io Client

# @feathersjs/socketio-client

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npm install @feathersjs/socketio-client --save

The @feathersjs/socketio-client module allows to connect to services exposed through the Socket.io transport via a Socket.io socket.

Note: We recommend using Feathers and the @feathersjs/socketio-client module on the client if possible. If however, you want to use a direct Socket.io connection without using Feathers on the client, see the Direct connection section.

Important: Socket.io is also used to call service methods. Using sockets for both calling methods and receiving real-time events is generally faster than using REST. There is therefore no need to use both REST and Socket.io in the same client application.

# socketio(socket)

Initialize the Socket.io client using a given socket and the default options.

    # socketio(socket, options)

    Initialize the Socket.io client with the specified socket and options.

    Options can be:

    • timeout (default: 5000ms) - The time after which a method call fails and times out. This usually happens when calling a service or service method that does not exist.
    const feathers = require('@feathersjs/feathers');
const socketio = require('@feathersjs/socketio-client');
const io = require('socket.io-client');

const socket = io('http://api.feathersjs.com');
const app = feathers();

// Set up Socket.io client with the socket
// And a timeout of 2 seconds
app.configure(socketio(socket, {
  timeout: 2000
}));

    To set a service specific timeout you can use:

    app.service('messages').timeout = 3000;

    # app.io

    app.io contains a reference to the socket object passed to socketio(socket [, options])

    app.io.on('disconnect', (reason) => {
  // Show offline message
});

    # Direct connection

    Feathers sets up a normal Socket.io server that you can connect to with any Socket.io compatible client, usually the Socket.io client (opens new window) either by loading the socket.io-client module or /socket.io/socket.io.js from the server. Unlike HTTP calls, websockets do not have an inherent cross-origin restriction in the browser so it is possible to connect to any Feathers server. Additionally query parameter types do not have to be converted from strings as they do for REST requests.

    ProTip: The socket connection URL has to point to the server root which is where Feathers will set up Socket.io.

    <!-- Connecting to the same URL -->
<script src="/socket.io/socket.io.js"></script>
<script>
  var socket = io();
</script>

<!-- Connecting to a different server -->
<script src="http://localhost:3030/socket.io/socket.io.js"></script>
<script>
  var socket = io('http://localhost:3030/');
</script>

    Service methods can be called by emitting a <methodname> event followed by the service path and method parameters. The service path is the name the service has been registered with (in app.use), without leading or trailing slashes. An optional callback following the function(error, data) Node convention will be called with the result of the method call or any errors that might have occurred.

    params will be set as params.query in the service method call. Other service parameters can be set through a Socket.io middleware.

    If the service path or method does not exist, an appropriate Feathers error will be returned.

    # Authentication

    There are two ways to establish an authenticated Socket.io connection. Either by calling the authentication service or by sending authentication headers.

    # Via authentication service

    Sockets will be authenticated automatically by calling .create on the authentication service:

    const io = require('socket.io-client');
const socket = io('http://localhost:3030');

socket.emit('create', 'authentication', {
  strategy: 'local',
  email: 'hello@feathersjs.com',
  password: 'supersecret'
}, function(error, authResult) {
  console.log(authResult); 
  // authResult will be {"accessToken": "your token", "user": user }
  // You can now send authenticated messages to the server
});

    Important: When a socket disconnects and then reconnects, it has to be authenticated again before making any other request that requires authentication. This is usually done with the jwt strategy using the accessToken from the authResult. The authentication client handles this already automatically.

    socket.on('connect', () => {
  socket.emit('create', 'authentication', {
    strategy: 'jwt',
    accessToken: authResult.accessToken
  }, function(error, newAuthResult) {
    console.log(newAuthResult); 
  });
});

    # Via handshake headers

    If the authentication strategy (e.g. JWT or API key) supports parsing headers, an authenticated websocket connection can be established by adding the information in the extraHeaders option (opens new window):

    const io = require('socket.io-client');
const socket = io('http://localhost:3030', {
  extraHeaders: {
    Authorization: `Bearer <accessToken here>`
  }
});

    Note: The authentication strategy needs to be included in the authStrategies option.

    # find

    Retrieves a list of all matching resources from the service

    socket.emit('find', 'messages', { status: 'read', user: 10 }, (error, data) => {
  console.log('Found all messages', data);
});

    Will call app.service('messages').find({ query: { status: 'read', user: 10 } }) on the server.

    # get

    Retrieve a single resource from the service.

    socket.emit('get', 'messages', 1, (error, message) => {
  console.log('Found message', message);
});

    Will call app.service('messages').get(1, {}) on the server.

    socket.emit('get', 'messages', 1, { fetch: 'all' }, (error, message) => {
  console.log('Found message', message);
});

    Will call app.service('messages').get(1, { query: { fetch: 'all' } }) on the server.

    # create

    Create a new resource with data which may also be an array.

    socket.emit('create', 'messages', {
  text: 'I really have to iron'
}, (error, message) => {
  console.log('Todo created', message);
});

    Will call app.service('messages').create({ text: 'I really have to iron' }, {}) on the server.

    socket.emit('create', 'messages', [
  { text: 'I really have to iron' },
  { text: 'Do laundry' }
]);

    Will call app.service('messages').create with the array.

    # update

    Completely replace a single or multiple resources.

    socket.emit('update', 'messages', 2, {
  text: 'I really have to do laundry'
}, (error, message) => {
  console.log('Todo updated', message);
});

    Will call app.service('messages').update(2, { text: 'I really have to do laundry' }, {}) on the server. The id can also be null to update multiple resources:

    socket.emit('update', 'messages', null, {
  complete: true
}, { complete: false });

    Will call app.service('messages').update(null, { complete: true }, { query: { complete: 'false' } }) on the server.

    ProTip: update is normally expected to replace an entire resource, which is why the database adapters only support patch for multiple records.

    # patch

    Merge the existing data of a single or multiple resources with the new data.

    socket.emit('patch', 'messages', 2, {
  read: true
}, (error, message) => {
  console.log('Patched message', message);
});

    Will call app.service('messages').patch(2, { read: true }, {}) on the server. The id can also be null to update multiple resources:

    socket.emit('patch', 'messages', null, {
  complete: true
}, {
  complete: false
}, (error, message) => {
  console.log('Patched message', message);
});

    Will call app.service('messages').patch(null, { complete: true }, { query: { complete: false } }) on the server, to change the status for all read app.service('messages').

    # remove

    Remove a single or multiple resources:

    socket.emit('remove', 'messages', 2, { cascade: true }, (error, message) => {
  console.log('Removed a message', message);
});

    Will call app.service('messages').remove(2, { query: { cascade: true } }) on the server. The id can also be null to remove multiple resources:

    socket.emit('remove', 'messages', null, { read: true });

    Will call app.service('messages').remove(null, { query: { read: 'true' } }) on the server to delete all read app.service('messages').

    # Listening to events

    Listening to service events allows real-time behaviour in an application. Service events are sent to the socket in the form of servicepath eventname.

    # created

    The created event will be published with the callback data, when a service create returns successfully.

    var socket = io('http://localhost:3030/');

socket.on('messages created', function(message) {
  console.log('Got a new Todo!', message);
});

    # updated, patched

    The updated and patched events will be published with the callback data, when a service update or patch method calls back successfully.

    var socket = io('http://localhost:3030/');

socket.on('my/messages updated', function(message) {
  console.log('Got an updated Todo!', message);
});

socket.emit('update', 'my/messages', 1, {
  text: 'Updated text'
}, {}, function(error, callback) {
 // Do something here
});

    # removed

    The removed event will be published with the callback data, when a service remove calls back successfully.

    var socket = io('http://localhost:3030/');

socket.on('messages removed', function(message) {
  // Remove element showing the Todo from the page
  $('#message-' + message.id).remove();
});

    # Custom events

    Custom events can be listened to accordingly:

    var socket = io('http://localhost:3030/');

socket.on('messages myevent', function(data) {
  console.log('Got myevent event', data);
});

    Anything unclear or missing? Get help (opens new window) or Edit this page (opens new window)

    Last Updated: 11/17/2020, 3:17:03 PM

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