我在创建一个为我的 Socket.IO 库公开功能的模块时遇到了麻烦:

const sio = require('socket.io');
module.exports = function(server) {
  const io = sio(server);
  return {
    register: function(namespace) {
      let nsp = io.of(namespace);
      nsp.on('connect', function(socket) {
        // ...
      }
    }
  }
}

现在的问题是我如何在其他模块中使用它？在我的 app.js

我用 Express 创建了 server 并且可以用 require('./mysocketio')(server) 实例化模块但不能在其他模块中实例化，因为服务器不可用那里。解决这些循环依赖的好方法是什么？

最佳答案

您可以通过多种方式实现这些目标，例如:

• 将对象设置为全局命名空间。 (改变全局需求护理)
• 使用 module.exports 并要求其他文件中的对象。 (如果处理不当会导致循环依赖问题)
• 将实例作为参数传递给 Controller ​​，同时在路由中要求它们。

myModule.js 公开 Socket.IO 库功能的模块

const sio = require('socket.io');
module.exports = function(server) {
  const io = sio(server);
  return {
    register: function(namespace) {
      let nsp = io.of(namespace);
      nsp.on('connect', function(socket) {
        // ...
      }
    }
  }
}

流程 1:在全局命名空间中设置模块。

app.js

var app = require('express').createServer();
var io = require('./myModule')(app);
global._io = io;

app.listen(80)

controller.js

module.exports = function(io){
    var that={};
    /*
     * Private local variable
     * made const so that 
     * one does not alter it by mistake
     * later on.
     */
    const _io = global._io; 

    that.myAction = function(req,res){

        _io.register('newRoom');
        res.send('Done');   
    }
    return that;
}

流程 2: 将模块作为参数传递。

app.js

var app = require('express').createServer();
var io = require('./myModule')(app);

require(./router.js)(app,io);

app.listen(80);

router.js

/*
 * Contains the routing logic
 */
module.exports = function (app,io) {
//passing while creating the instance of controller for the first time.
var controller = require("./controller")(io);

app.get('/test/about',controller.myAction);
};

controller.js

module.exports = function(io){
    var that={};

    const _io = io; 

    that.myAction = function(req,res){

        _io.register('newsRoom');
        res.send('Done');   
    }

    // everything attached to that will be exposed
    // more like making public member functions and properties.
    return that;
}

流程 3: 将 io 设置为全局。因此无需每次都通过服务器。

app.js

var app = require('express').createServer();
require('./myModule')(app);

require(./router.js)(app);

app.listen(80);

controller.js

// no need to pass the server as io is already initialized
const _io = require('./myModule')();

module.exports = function(io){
    var that={};

    that.myAction = function(req,res){

        _io.register('newsRoom');
        res.send('Done');   
    }
    return that;
}

myModule.js

module.exports = function( server ) {

  const _io = global._io || require('socket.io')(server);

  if(global._io === undefined){
    //initializing io for future use
    global._io = _io;
  }

  return {
    register: function(namespace) {
      let nsp = _io.of(namespace);
      nsp.on('connect', function(socket) {
        // ...
      }
    }
  }
}

Probably, the cleanest way is to pass is as arguments to the controllers, while requiring them in routes. Although 3rd flow seems promising but one should be care full while altering the global namespace.

关于javascript - 如何创建可重用的 Socket.IO 模块，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/37262923/