Socket.io Client

socketio-client

npm install @feathersjs/socketio-client socket.io-client --save

The @feathersjs/socketio-client module allows to connect to services exposed through the Socket.io transport via a Socket.io socket. We recommend using Feathers and the @feathersjs/socketio-client module on the client if possible since it can also handle reconnection and reauthentication. 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.

import { feathers } from '@feathersjs/feathers'
import socketio from '@feathersjs/socketio-client'
import io from 'socket.io-client'

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

// Set up Socket.io client with the socket
app.configure(socketio(socket))

// Receive real-time events through Socket.io
app.service('messages').on('created', (message) => console.log('New message created', message))

// Call the `messages` service
app.service('messages').create({
  text: 'A message from a REST client'
})

app.io

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

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

Custom Methods

On the client, custom service methods are also registered using the methods option when registering the service via socketClient.service():

import { feathers } from '@feathersjs/feathers'
import type { Params } from '@feathersjs/feathers'
import socketio from '@feathersjs/socketio-client'
import type { SocketService } from '@feathersjs/socketio-client'
import io from 'socket.io-client'

// `data` and return type of custom method
type CustomMethodData = { name: string }
type CustomMethodResponse = { acknowledged: boolean }

type ServiceTypes = {
  // The type is a Socket service extended with custom methods
  myservice: SocketService & {
    myCustomMethod(data: CustomMethodData, params: Params): Promise<CustomMethodResponse>
  }
}

const socket = io('http://api.feathersjs.com')
const client = feathers<ServiceTypes>()
const socketClient = socketio(socket)

// Set up Socket.io client with the socket
client.configure(socketClient)

// Register a socket client service with all methods listed
client.use('myservice', socketClient.service('myservice'), {
  methods: ['find', 'get', 'create', 'update', 'patch', 'remove', 'myCustomMethod']
})

// Then it can be used like other service methods
client.service('myservice').myCustomMethod(data, params)

info

Just like on the server all methods you want to use have to be listed in the methods option.

Route placeholders

Service URLs can have placeholders, e.g. users/:userId/messages. (see in express or koa)

You can call the client with route placeholders in the params.route property:

import { feathers } from '@feathersjs/feathers'
import socketio from '@feathersjs/socketio-client'
import io from 'socket.io-client'

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

// Set up Socket.io client with the socket
app.configure(socketio(socket))

// Call `users/2/messages`
app.service('users/:userId/messages').find({
  route: {
    userId: 2
  }
})

This can also be achieved by using the client bundled, sharing several servicePath variable exported in the service shared file file.

import rest from '@feathersjs/rest-client'

const connection = rest('https://myapp.com').fetch(window.fetch.bind(window))

const client = createClient(connection)

// Call the `https://myapp.com/users/2/messages` URL
client.service(usersMyMessagesPath).find({
  route: {
    userId: 2
  }
})

import io from 'socket.io-client'
import socketio from '@feathersjs/socketio-client'
import { createClient, usersMessagesPath } from 'my-app'

const socket = io('http://api.my-feathers-server.com')
const connection = socketio(socket)

const client = createClient(connection)

const messageService = client.service('users/:userId/messages')

// Call `users/2/messages`
app.service('users/:userId/messages').find({
  route: {
    userId: 2
  }
})

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 either by loading the socket.io-client module or /socket.io/socket.io.js from the server. Query parameter types do not have to be converted from strings as they do for REST requests.

Important

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:

import io from '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:

import io from '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 configuration.

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, { status: 'read' }, (error, message) => {
  console.log('Found message', message)
})

Will call app.service('messages').get(1, { query: { status: 'read' } }) 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,
  {
    status: 'unread'
  },
  { status: 'read' }
)

Will call app.service('messages').update(null, { status: 'read' }, { query: { satus: 'unread' } }) on the server.

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,
  {
    status: 'read'
  },
  {
    status: 'unread'
  },
  (error, message) => {
    console.log('Patched message', message)
  }
)

Will call app.service('messages').patch(null, { status: 'read' }, { query: { status: 'unread' } }) 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, {}, (error, message) => {
  console.log('Removed a message', message)
})

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

socket.emit('remove', 'messages', null, { status: 'archived' })

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

Custom methods

Custom service methods can be called directly via Socket.io by sending a socket.emit(methodName, serviceName, data, query) message:

socket.emit('myCustomMethod', 'myservice', { message: 'Hello world' }, {}, (error, data) => {
  console.log('Called myCustomMethod', data)
})

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.

const socket = io('http://localhost:3030/')

socket.on('messages created', (message: 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.

const socket = io('http://localhost:3030/')

socket.on('my/messages updated', (message: Message) => {
  console.log('Got an updated Todo!', message)
})

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

removed

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

const socket = io('http://localhost:3030/')

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

Custom events

Custom events can be listened to accordingly:

const socket = io('http://localhost:3030/')

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