写在前面

ASP.NET SignalR 是一个开源代码库，简化了Web实时通讯方案，可以实时地通过服务端将信息同步推送到各个客户端，可应用于
需要从服务器进行高频更新的应用：包括游戏、社交网络、投票、拍卖、地图和GPS应用；
仪表盘和监视应用：包括公司仪表板、即时销售更新或旅行报警；
协同类应用：包括白板应用和团队会议软件；
通知应用：社交网络、电子邮件、聊天、游戏、旅行报警和其他应用都需要使用的通知。

通常情况下 SignalR 优先使用 WebSocket 进行传输，在浏览器不支持WebSocket的情况下才会采用旧的Http传输方式。

本文主要参考官方示例：

ASP.NET Core SignalR 入门 | Microsoft Learn

项目结构 如下： 

 需要添加客户端库 

 

代码实现

服务端实现

using SignalRChat.Hubs;var builder = WebApplication.CreateBuilder(args);// Add services to the container.
builder.Services.AddRazorPages();
builder.Services.AddSignalR();var app = builder.Build();// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{app.UseExceptionHandler("/Error");// The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.app.UseHsts();
}app.UseHttpsRedirection();
app.UseStaticFiles();app.UseRouting();app.UseAuthorization();app.MapRazorPages();
app.MapHub<ChatHub>("/chatHub");app.Run();

using Microsoft.AspNetCore.SignalR;namespace SignalRChat.Hubs
{public class ChatHub : Hub{public async Task SendMessage(string user, string message){await Clients.All.SendAsync("ReceiveMessage", user, message);}}
}

 

客户端实现

"use strict";var connection = new signalR.HubConnectionBuilder().withUrl("/chatHub").build();//Disable the send button until connection is established.
document.getElementById("sendButton").disabled = true;connection.on("ReceiveMessage", function (user, message) {var li = document.createElement("li");document.getElementById("messagesList").appendChild(li);// We can assign user-supplied strings to an element's textContent because it// is not interpreted as markup. If you're assigning in any other way, you // should be aware of possible script injection concerns.li.textContent = `${user} says ${message}`;
});connection.start().then(function () {document.getElementById("sendButton").disabled = false;
}).catch(function (err) {return console.error(err.toString());
});document.getElementById("sendButton").addEventListener("click", function (event) {var user = document.getElementById("userInput").value;var message = document.getElementById("messageInput").value;connection.invoke("SendMessage", user, message).catch(function (err) {return console.error(err.toString());});event.preventDefault();
});

调用示例