redux-socket.io-middleware

Another dead-simple middleware which allows you to connect Redux and Socket.io. It uses meta property of your action object to recognize whether send it to backend, or not.

Idea

• Whenever you want to send an event from Client to your Backend through socket.io, use store.dispatch with regular action with meta object (see example actionCreator.js)
• Whenever you want to send and handle an event from your Backend to Client - emit it on backend with socket.io in a form of regular action and it will be handled by forwarding it to store.dispatch() - your reducers should take care of the rest.

Important side note - action object send thorough Socket.io must be standard javascript object literal. It can't be a function (so unfortunately thunk drops out).

Usage

Installation

npm install --save redux-socket.io-middleware

Client side

store.js

import socketIO from 'socket.io-client';
import socketIoMiddleware from 'redux-socket.io-middleware'

const reducers = (...);

const io = socketIO.connect(`http://localhost:3030`);

const store = createStore(
  reducers,
  applyMiddleware(    
    socketIoMiddleware(io)
  )
);

actionCreator.js

function addUserRequest(user){
  return {
    type: "ADD_USER_REQUEST",
    meta: {remote: true},
    user
  }
}

function addUserRequestSuccess() {
	return {
    	type: "ADD_USER_REQUEST_SUCCESS",       
  }
}

function addUserRequestFailure() {
	return {
    	type: "ADD_USER_REQUEST_FAILURE",       
  	}
}

And then you dispatch this type of action like any other:

yourReactComponentContainer.js

const mapDispatchToProps = function (dispatch) {
  return {
    addUserRequest: (user) => dispatch(actionCreator.addUserRequest(user)),
    }
}

Server side

If we share actionCreator.js between client and server we can youse it like below. Otherwise, just create action by hand.

userController.js

io.on('connection', function (socket) {
    socket.on("action", function (action) {
      switch (action.type) {
        case "ADD_USER_REQUEST":
          return userService.save(action.user).then(
            (user) => io.emit('action', actionCreator.addUserRequestSuccess()),
            (err) => io.emit('action', actionCreator.addUserRequestFailure())
          );
          }
    })
});

Configuration

You can configure the name of channel which will be used for sending websocket messages. Default value is action. To change it, simply add second parameter when registering middleware:

import socketIoMiddleware from './redux-socket.io-middleware'

const store = createStore(
  reducers,
  applyMiddleware(    
    socketIoMiddleware(io, "myRandomChannel")
  )
);

and then on your backend side, listen on that string:

  io.on('connection', function (socket) {
      socket.on("myRandomChannel", function (action) {
        /// ...
      })
  });

Yeah, I know that this readme is much longer than a code itself :)