io.adapter如何在引擎盖下工作？ [英] How io.adapter works under the hood?

问题描述

我正在使用由node.js + express + socket.io提供的1-1个聊天室应用程序。
我正在追踪文章： Socket.IO - 房间和命名空间

I'm working on 1-1 chat rooms application powered by node.js + express + socket.io. I am following the article: Socket.IO - Rooms and Namespaces

在本文中，他们演示了如何使用模块 socket.io-redis

In the article they demonstrate how to initiate the io.adapter using the module socket.io-redis:

var io = require('socket.io')(3000);
var redis = require('socket.io-redis');
io.adapter(redis({ host: 'localhost', port: 6379 }));

两个问题：

Two questions:

1. 在文档中，他们提到另外两个参数： pubClient 和 subClient 。我应该提供吗？有什么区别？


2. io.adapter的行为如何？例如，如果用户A连接到服务器A，用户B是服务器B，并且他们想要相互交谈。

1. In the docs, They are mentioning two more arguments: pubClient and subClient. Should I supply them? What's the difference?
2. How the io.adapter behaves? For example, if user A is connected to server A and user B is server B, and they want to "talk" with each other. What's going under the hood?

谢谢。

推荐答案

1. 您不需要传递自己的pubClient / subClient。如果您传递主机/端口，将为您创建。但是，如果您想要自己创建，无论什么原因（例如，您想要调整重新连接超时），您将创建这两个客户端并将其传递给适配器。

1. You do not need to pass your own pubClient/subClient. If you pass host/port, they will be created for you. But, if you want to create them yourself, for any reason (e.g. you want to tweak reconnection timeouts), you create those 2 clients and pass it to adapter.

适配器广播全部内部发送。所以，它给你集群功能。例如。假设您有聊天应用程序，并且在负载平衡器后面有3个node.js服务器（因此它们共享单个URL）。还假设6个不同的浏览器连接到负载均衡器URL，并将它们路由到3个独立的node.js进程，每个node.js服务器有2个用户。如果客户端＃1发送消息，node.js＃1将执行类似 io.to（'chatroom'）的操作。emit（'来自用户＃1'的msg）。没有适配器，服务器＃1用户将接收到发射，但不会剩余4个用户。但是，如果使用适配器，则node.js＃2和node.js＃3的其余部分将会收到发送完成的信息，并向其客户端发出相同的发送信息，所有6个用户将收到初始消息。

The adapter broadcasts all emits internally. So, it gives you the cluster feature. E.g. lets suppose that you have chat application, and you have 3 node.js servers behind load balancer (so they share single URL). Lets also assume that 6 different browsers connect to load balancer URL and they are routed to 3 separate node.js processes, 2 users per node.js server. If client #1 sends a message, node.js #1 will do something like io.to('chatroom').emit('msg from user #1'). Without adapter, both server #1 users will receive the emit, but not the remaining 4 users. If you use adapter, however, remaining node.js #2 and node.js #3 will receive info that emit was done and will issue identical emit to their clients - and all 6 users will receive initial message.

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