我想要一个跨网络工作的事件发射器 [英] I want an eventemitter that works across a network

问题描述

我真的很喜欢 EventEmitter 范式，我想用它来通过网络在两个程序之间进行通信.

I really like the EventEmitter paradigm, and I'd like to use it to communicate between two programs across a network.

我想出了自己的SockEmitter，但我想知道:我做错了吗(tm)"?是否有一些软件包已经可以做到这一点?是否有更适合跨网络通信的不同范式?

I came up with my own SockEmitter, but I want to know: am I "doing it wrong(tm)"? Is there some package that will already do this? Is there a different paradigm that works better for communicating across a network?

这是我所拥有的:

var JsonSocket = require('json-socket')

// An event emitter that uses a JsonSocket.
// emit passes things over the wire, and data received
// over the wire calls the listeners.
//
// As a result, se.on('foo', console.log); se.emit('foo', 5)
// won't do what you might normally expect from an emitter.

function SockEmitter(socket) {
  this._listeners = {}
  this.sock = new JsonSocket(socket)
  this.sock.on('message', this._message.bind(this))
}

SockEmitter.prototype = {
  on: function (type, handler) {
    if (!this._listeners[type]) {
      this._listeners[type] = [];
    }
    this._listeners[type].push(handler)
  },
  off: function (type, handler) {
    if (!this._listeners[type]) {
      return false
    }
    var idx = this._listeners[type].indexOf(handler)
    if (idx === -1) return false
    this._listeners[type].splice(idx, 1)
  },
  emit: function (type) {
    var args = [].slice.call(arguments, 1)
    this.sock.sendMessage({type: type, args: args})
  },
  _message: function (message) {
    if (!message || !message.type || !Array.isArray(message.args)) {
      return console.error('Invalid message received: %s', message)
    }
    if (!this._listeners[message.type]) return
    this._listeners[message.type].forEach(function (handler) {
      handler.apply(null, message.args)
    })
  }
}

推荐答案

Socket.io 经常被提出来做这样的事情.它以事件的方式提供 2 路通信.但是，人们经常查看服务器发送的事件这是使用标准 http 消息的单向事件的 W3C 标准(而不是像 socket.io 那样对自定义协议执行 UPGRADE).

Socket.io is often brought up for something like this. It provides 2 way communication in an evented way. However, people often look over Server Sent Events which is a W3C standard for 1-way eventing that uses standard http messages (rather than doing an UPGRADE to a custom protocol like socket.io does).

使用SSE，您可能会看到许多专注于服务器到浏览器通信的文章，但该规范定义了一个简单的基于 http 的消息结构，可用于您想要的任何内容(例如:服务器到服务器).

With SSE, you will probably see many articles focused on server-to-browser communication, but the the spec defines a simple http based message structure which can be used for whatever you want (eg: server-to-server).

我一直在使用它并取得了巨大的成功.我可以构建事件服务器到服务器的东西，然后也可以轻松地与浏览器连接，这真是太棒了.正如预期的那样，IE 尚未支持，但大多数浏览器都支持.

I've been using it with great success. It is fantastic that I can build evented server-to-server things- and then easily connect with a browser too. As expected, IE isn't onboard yet but most browsers are.

有很多 SSE npm 模块.我已经将 eventsource-node 用于聆听"结束并取得了巨大成功.当我开始使用 SSE 时，没有用于发送事件的模块——只有用于监听的模块；所以我写了我自己的.不过这没什么大不了的——协议非常简单，只需要大约 100 行代码.我相信其中一个已发布的模块会很好用.

There are many SSE npm modules. I have used eventsource-node for the "listening" end with great success. When I got started with SSE, there were no modules for sending events- just modules for listening; so I wrote my own. It was no a big deal though- the protocol is so dead simple that it only took about 100 lines of code. I'm sure one of the published modules will work great.

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