go语言如何使用gin库实现SSE长连接

import (
	"encoding/json"
	"fmt"
	"github.com/gin-gonic/gin"
	"github.com/labstack/gommon/log"
	"net/http"
	"strings"
	"time"
)
 
var ifChannelsMapInit = false
 
var channelsMap = map[string]chan string{}
 
func initChannelsMap() {
	channelsMap = make(map[string]chan string)
}
 
func AddChannel(userEmail string, traceId string) {
	if !ifChannelsMapInit {
		initChannelsMap()
		ifChannelsMapInit = true
	}
	var newChannel = make(chan string)
	channelsMap[userEmail+traceId] = newChannel
	log.Infof("Build SSE connection for user = " + userEmail + ", trace id = " + traceId)
}
 
func BuildNotificationChannel(userEmail string, traceId string, c *gin.Context) {
	AddChannel(userEmail, traceId)
	c.Writer.Header().Set("Content-Type", "text/event-stream")
	c.Writer.Header().Set("Cache-Control", "no-cache")
	c.Writer.Header().Set("Connection", "keep-alive")
	w := c.Writer
	flusher, _ := w.(http.Flusher)
	closeNotify := c.Request.Context().Done()
	go func() {
		<-closeNotify
		delete(channelsMap, userEmail+traceId)
		log.Infof("SSE close for user = " + userEmail + ", trace id = " + traceId)
		return
	}()
	fmt.Fprintf(w, "data: %s\n\n", "--ping--")
	flusher.Flush()
	for msg := range channelsMap[userEmail+traceId] {
		fmt.Fprintf(w, "data: %s\n\n", msg)
		flusher.Flush()
	}
}

func SendNotification(userEmail string, messageBody string, actionType string) {
	log.Infof("Send notification to user = " + userEmail)
	var msg = dao.NotificationLog{}
	msg.MessageBody = messageBody
	msg.UserEmail = userEmail
	msg.Type = actionType
	msg.Status = UNREAD
	msg.CreateTime = time.Now()
	msg.Create()
	msgBytes, _ := json.Marshal(msg)
	for key := range channelsMap {
		if strings.Contains(key, userEmail) {
			channel := channelsMap[key]
			channel <- string(msgBytes)
		}
	}
}

GroupV1Rest.GET("/notification/socket-connection", controllers.SocketConnection)
GroupV1Rest.GET("/notification/export-excel", controllers.ExportExcel)

e = new EventSource('/business/v1/notification/socket-connection');
e.onmessage = function(event) {
    console.log(event.data);
};