zoukankan      html  css  js  c++  java
  • Socket.io 0.7 – Sending messages to individual clients

    Note that this is just for Socket.io version 0.7, and possibly higher if they don’t change the API again.

    I’m writing an iPhone app right now using PhoneGap and jQuery Mobile on the phone, and node.js and socket.io on an Amazon EC2 server, and I hit a wall when I started using Socket.io. The problem is that the documentation is sparse, disorganized, and hard to find. In addition to that, there are dozens of blog posts and community members who’ll teach you how to do things in older versions of socket, but the API has changed, so you just end up with undefined errors.

    My exact problem was with sending messages to individual clients.

    // on the server
    var users = {};
    io.sockets.on('connection', function (socket) {
        socket.emit('who are you');
        socket.on('check in', function (incoming) {
            users[incoming.phonenumber] = socket.id;
        });
    });
    
    // on the client
    socket.on('who are you', function (incoming) {
        socket.emit('check in', {phonenumber: savedphonenumber});
    });
    

    To recap: The server is listening for connections. When a client connects, the server emits the custom message “who are you”. The client hears it and responds with it’s identifier (I’m using their phone number, which I verify and store earlier in the process). The server then stores the client’s socket ID in a users object, with their identifier as the key, and the socket ID as the value.

    From then on, it’s a simple case of grabbing the user’s socket ID from the user’s table when you need to send them a message, and sending it like this:

    var socketid = users[clientphonenumber];
    io.sockets.socket(socketid).emit('for your eyes only');
    

    One thing to consider is what happens to that users object if you have thousands of users. It’ll get pretty bloated, pretty quickly. You need to figure out a strategy for removing users from the users object if they disconnect AND if you don’t hear from them in a while (in case the disconnect event doesn’t fire).

    Source:http://chrissilich.com/blog/socket-io-0-7-sending-messages-to-individual-clients/

  • 相关阅读:
    UWP&WP8.1 基础控件——Grid
    UWP&WP8.1 基础控件——Border
    UWP&WP8.1 基础控件——Image
    UWP&WP8.1 基础控件—Button
    UWP&WP8.1 基础控件—TextBlock和TextBox
    UWP &WP8.1 依赖属性和用户控件 依赖属性简单使用 uwp添加UserControl
    UWP_开源小程序 水印添加器
    UWP&WP8.1 附加属性 和WebView的NavigateToString方法XAML绑定方法
    Sql Server 中锁的概念
    MSSQL 查询表空间
  • 原文地址:https://www.cnblogs.com/liuswi/p/4024563.html
Copyright © 2011-2022 走看看