实时通讯

过完2018年最后一个长假，看了年初给自己的flag，默默的发现距离感还是很强的。。。。

先说正题，最近在项目中碰到了实时通讯的需求，翻看了很多资料，最终选取signalr。

附上链接 https://www.asp.net/signalr 

项目是基于Angular4的，后端采用的Abp框架，自带通知架构。(https://aspnetboilerplate.com/Pages/Documents/Notification-System)

先说怎么将signalr引入项目中。

1、npm i signalr

在angular-cli.json文件里引入："../node_modules/signalr/jquery.signalR.js"

2、建立连接

var connection = $.hubConnection();
var contosoChatHubProxy = connection.createHubProxy('contosoChatHub');
contosoChatHubProxy.on('addContosoChatMessageToPage', function(name, message) {
    console.log(name + ' ' + message);
});
connection.start().done(function() {
    // Wire up Send button to call NewContosoChatMessage on the server.
    $('#newContosoChatMessage').click(function () {
        contosoChatHubProxy.invoke('newContosoChatMessage', $('#displayname').val(), $('#message').val());
        $('#message').val('').focus();
                });
    });

3、后端配合

后端主要在于跨域，微软的官方文档里也有写到如何解决（https://docs.microsoft.com/en-us/aspnet/signalr/overview/guide-to-the-api/hubs-api-guide-javascript-client#how-to-establish-a-cross-domain-connection）

4、代码基本：using Microsoft.AspNet.SignalR;
using Microsoft.Owin.Cors;
using Owin;
namespace MyWebApplication
{
    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            // Branch the pipeline here for requests that start with "/signalr"
            app.Map("/signalr", map =>
            {
                // Setup the CORS middleware to run before SignalR.
                // By default this will allow all origins. You can
                // configure the set of origins and/or http verbs by
                // providing a cors options with a different policy. map.UseCors(CorsOptions.AllowAll); var hubConfiguration = new HubConfiguration
                {
                    // You can enable JSONP by uncommenting line below.
                    // JSONP requests are insecure but some older browsers (and some
                    // versions of IE) require JSONP to work cross domain
                    // EnableJSONP = true
                };
                // Run the SignalR pipeline. We're not using MapSignalR
                // since this branch already runs under the "/signalr"
                // path.
                map.RunSignalR(hubConfiguration);
            });
        }
    }
}

基础部分很是简单通透

在消息处理这一块，ABP已经处理的很好了，只要调取相应的方法即可。区分一下消息的时效性（暂时的消息还是永久性的消息）。