base-golang/pkg/sse/server.go

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2024-07-23 10:23:43 +08:00
package sse
import (
"github.com/gin-gonic/gin"
"io"
"net/http"
"sync"
"sync/atomic"
)
var _ Server = (*event)(nil)
type Server interface {
HandlerFunc(auth func(c *gin.Context) (string, error)) gin.HandlerFunc
Push(user, name, msg string) bool
Broadcast(name, msg string)
}
type clientChan struct {
User string
Chan chan msgChan
}
type msgChan struct {
Name string
Message string
}
type event struct {
SessionList sync.Map
Count atomic.Int32
Register chan clientChan
Unregister chan string
}
func NewServer() Server {
e := &event{
SessionList: sync.Map{},
Count: atomic.Int32{},
Register: make(chan clientChan),
Unregister: make(chan string),
}
go e.listen()
return e
}
func (stream *event) listen() {
for {
select {
case client := <-stream.Register:
stream.SessionList.Store(client.User, client.Chan)
stream.Count.Add(1)
case user := <-stream.Unregister:
value, ok := stream.SessionList.Load(user)
if ok {
event := value.(chan msgChan)
close(event)
stream.SessionList.Delete(user)
stream.Count.Add(-1)
}
}
}
}
func (stream *event) HandlerFunc(auth func(c *gin.Context) (string, error)) gin.HandlerFunc {
return func(c *gin.Context) {
user, err := auth(c)
if err != nil {
c.AbortWithStatus(http.StatusBadRequest)
return
}
e := make(chan msgChan)
client := clientChan{
User: user,
Chan: e,
}
stream.Register <- client
defer func() {
stream.Unregister <- user
}()
c.Writer.Header().Set("Content-Type", "text/event-stream")
c.Writer.Header().Set("Cache-Control", "no-cache")
c.Writer.Header().Set("Connection", "keep-alive")
c.Writer.Header().Set("Transfer-Encoding", "chunked")
c.Stream(func(w io.Writer) bool {
if msg, ok := <-e; ok {
c.SSEvent(msg.Name, msg.Message)
return true
}
return false
})
c.Next()
}
}
func (stream *event) Push(user, name, msg string) bool {
value, ok := stream.SessionList.Load(user)
if ok {
val := value.(chan msgChan)
val <- msgChan{Name: name, Message: msg}
}
return false
}
func (stream *event) Broadcast(name, msg string) {
stream.SessionList.Range(func(user, value any) bool {
val := value.(chan msgChan)
val <- msgChan{Name: name, Message: msg}
return true
})
}