1. 添加SignalR服务

builder.Services.AddSignalR(configure =>
{
    configure.ClientTimeoutInterval = TimeSpan.FromMinutes(3);
    configure.KeepAliveInterval = TimeSpan.FromMinutes(1);
});

2. 创建自己的Hub

// 这里的hub是空的，是因为不需要客户端调用服务端，我们只实现SSE，既服务端向客户端发送通知
public class NotificationHub : Hub
{
}

3. 创建通知服务并添加到容器中

public class NotificationMessage
{
    public string Type { get; set; } = null!;

    public object? Data { get; set; } = null!;
}

public interface INotificationService
{
    Task SendMessageAsync(NotificationMessage message);
}

public class NotificationService(IHubContext<NotificationHub> context) : INotificationService
{
    public async Task SendMessageAsync(NotificationMessage message)
    {
        await context.Clients.All.SendAsync("ReceiveMessage", JsonConvert.SerializeObject(message));
    }
}

builder.Services.AddScoped<INotificationService, NotificationService>();

4. 将Hub配置到请求管道

app.MapHub<NotificationHub>("/api/notificationhub");

5. 使用vue接收通知

import { HubConnectionBuilder, LogLevel, HttpTransportType } from '@microsoft/signalr'
import { defineStore } from "pinia"
import { onMounted, ref } from 'vue'

export const useNotificationStore = defineStore('notification', () => {
    const funcs = ref([])
    onMounted(() => {
        initialize()
    })
    function initialize() {
        const connection = new HubConnectionBuilder()
            .withKeepAliveInterval(60000)
            .withServerTimeout(180000)
            .withUrl("/api/notificationhub", {
                transport: HttpTransportType.ServerSentEvents,
            })
            .withAutomaticReconnect()
            .configureLogging(LogLevel.Information)
            .build()

        connection.on("ReceiveMessage", (json) => {
            funcs.value.forEach(func => {
                try {
                    func(JSON.parse(json))
                } catch (error) {
                    console.error(error)
                }
            })
        })
        start()
        async function start() {
            try {
                await connection.start()
            } catch (err) {
                console.error("Failed to connect with SSE", err)
                setTimeout(start, 5000)
            }
        }
    }

    function onReceived(func) {
        funcs.value.push(func)
    }

    return {
        onReceived
    }
})

如此一个最简单的SSE就完成了。