egg-socket.io

egg plugin for socket.io

Install

$ npm i egg-socket.io --save

Requirements

• Node.js >= 8.0
• Egg.js >= 2.0

Configuration

Change ${app_root}/config/plugin.js to enable Socket.IO plugin:

// {app_root}/config/plugin.js
exports.io = {
  enable: true,
  package: 'egg-socket.io',
};

Configure Socket.IO in ${app_root}/config/config.default.js:

exports.io = {
  init: { }, // passed to engine.io
  namespace: {
    '/': {
      connectionMiddleware: [],
      packetMiddleware: [],
    },
  },
  redis: {
    host: '127.0.0.1',
    port: 6379
  }
};

uws

Egg’s socket is using ws, uws is deprecated due to some reasons.

If you insist using this, please config like this following:

exports.io = {
  init: { wsEngine: 'uws' },
};

• For more options in init : engine.io.
• For more configs of Egg Socket in default : config.default.js.

generateId

Note: This function is left on purpose to override and generate a unique ID according to your own rule:

exports.io = {
  generateId: (request) => {
        // Something like UUID.
        return 'This should be a random unique ID';
    }
};

Deployment

Node Conf

Because of socket.io’s design, the multi process socket.io server must work at sticky mode.

So, you must start cluster server with sticky set to true, otherwise it will cause handshake exception.

$ # modify your package.json - npm scripts
$ egg-bin dev --sticky
$ egg-scripts start --sticky

which will start egg cluster with:

startCluster({
  sticky: true,
  ...
});

Nginx Conf

if you use a nginx proxy server:

location / {
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_pass   http://127.0.0.1:{ your node server port };
}

Usage

Directory Structure

app
├── io
│   ├── controller
│   │   └── chat.js
│   └── middleware
│       ├── auth.js
│       ├── filter.js
├── router.js
config
 ├── config.default.js
 └── plugin.js

Middleware

middleware are functions which every connection or packet will be processed by.

Connection Middleware

• Write your connection middleware app/io/middleware/auth.js

  module.exports = app => {
    return async (ctx, next) => {
        ctx.socket.emit('res', 'connected!');
        await next();
        // execute when disconnect.
        console.log('disconnection!');
    };
  };

• then config this middleware to make it works.

config/config.default.js

exports.io = {
  namespace: {
    '/': {
      connectionMiddleware: ['auth'],
    },
  },
};

pay attention to the namespace, the config will only work for a specific namespace.

Packet Middleware

• Write your packet middleware app/io/middleware/filter.js

  module.exports = app => {
    return async (ctx, next) => {
        ctx.socket.emit('res', 'packet received!');
        console.log('packet:', this.packet);
        await next();
    };
  };

• then config this middleware to make it works.

config/config.default.js

exports.io = {
  namespace: {
    '/': {
      packetMiddleware: ['filter'],
    },
  },
};

pay attention to the namespace, the config will only work for a specific namespace.

Controller

controller is designed to handle the emit event from the client.

example:

app/io/controller/chat.js

module.exports = app => {
  class Controller extends app.Controller {
    async ping() {
      const message = this.ctx.args[0];
      await this.ctx.socket.emit('res', `Hi! I've got your message: ${message}`);
    }
  }
  return Controller
};

 // or async functions
exports.ping = async function() {
  const message = this.args[0];
  await this.socket.emit('res', `Hi! I've got your message: ${message}`);
};

next, config the router at app/router.js

module.exports = app => {
  // or app.io.of('/')
  app.io.route('chat', app.io.controller.chat.ping);
};

Router

A router is mainly responsible for distributing different events corresponding to a controller on a specific socket connection.

It should be configured at app/router.js refer to the last chapter.

Besides that, there are several system Event:

• disconnecting doing the disconnect
• disconnect connection has disconnected
• error Error occured

Example：

app/router.js

app.io.route('disconnect', app.io.controller.chat.disconnect);

app/io/controller/chat.js

module.exports = (app) => {
  class Controller extends app.Controller {
    async disconnect() {
      const message = this.ctx.args[0];
      console.log(message);
    }
  }
  return Controller
};

Session

The session is supported by egg-socket.io. It’s behaviour just like the normal HTTP session.

Session creates or check just happens at the handshake period. Session can be accessed by ctx.session in packetMiddleware and controller, but it’s only created at the handshake period.

The feature is powered by egg-session, make sure it has been enabled.

Cluster

If your Socket.IO service is powered by mutil server, you must think about cluster solution. It can’t work without cluster like broadcast, rooms and so on.

It’s very easy to implement sharing source and event dispatch with socket.io-redis built in.

config at config/config.${env}.js ：

exports.io = {
  redis: {
    host: { redis server host },
    port: { redis server prot },
    auth_pass: { redis server password },
    db: 0,
  }
};

Application will try to connect the redis server when booting.

Questions & Suggestions

Please open an issue here.

License

MIT