[RFC] egg-socket.io

Directory Structure

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

Configuration

// {app_root}/config/config.default.js
exports.io = {
  namespace: {
    '/': {
      connectionMiddleware: [],
      packetMiddleware: [],
    },
  },
  redis: {
    host: '127.0.0.1',
    port: 6379
  }
};

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 function* (next) {
        this.socket.emit('res', 'connected!');
        yield* 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 function* (next) {
        this.socket.emit('res', 'packet received!');
        console.log('packet:', this.packet);
        yield* 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 => {
  return function* () {
    const message = this.args[0];
    console.log(message);
    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.controllers.chat);
};

[dead-horse]

如果不混部，为什么要强行在 egg 里面支持 socket.io，我们设计的这一套 web 开发相关的规范本来就美为 socket.io 考虑，等于是要再造一个基于 socket.io 的上层框架，我们本身也没有类似的强需求，不应该做到 egg 里面。

1. 如果应用真的足够复杂（或者规模上去了），会有单独的 websocket 服务，适合单独部署，也不需要用 egg。
2. 当应用刚起步，在 web 网站的基础上有一些实时推送的需求，用 egg 开发网站服务，顺便用 egg-socket.io 解决实时推送问题。

我的看法是我们主要解决的第二类问题。

[calidion]

很好啊。 可以在所有的npm包里都打上egg-前缀，多么美妙的事情啊。哈哈。