bit4sat/websocket.go

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package main
import (
"bytes"
"log"
"net/http"
"time"
"github.com/gin-gonic/gin"
"github.com/gorilla/websocket"
)
const (
// Time allowed to write message to peer
writeWait = 10 * time.Second
// Time allowed to read the next pong message from the client.
pongWait = 5 * time.Second
// Send pings to client with this period. Must be less than pongWait.
pingPeriod = (pongWait * 9) / 10
//pingPeriod = 5 * time.Second
// Maximum message size
maxMessageSize = 512
)
var upgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
CheckOrigin: func(r *http.Request) bool {
return true
},
}
var (
conn *websocket.Conn
)
var (
newline = []byte{'\n'}
space = []byte{' '}
)
func reader() {
defer conn.Close()
conn.SetReadLimit(maxMessageSize)
conn.SetReadDeadline(time.Now().Add(pongWait))
conn.SetPongHandler(func(string) error {
//log.Println("pong")
conn.SetReadDeadline(time.Now().Add(pongWait))
return nil
})
for {
_, message, err := conn.ReadMessage()
if err != nil {
if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway,
websocket.CloseAbnormalClosure) {
log.Printf("error: %v", err)
}
break
}
message = bytes.TrimSpace(bytes.Replace(message, newline, space, -1))
}
}
func writer() {
pingTicker := time.NewTicker(pingPeriod)
defer func() {
log.Println("quit ws server")
pingTicker.Stop()
conn.Close()
}()
for {
select {
case <-pingTicker.C:
//log.Println("ping")
conn.SetWriteDeadline(time.Now().Add(writeWait))
if err := conn.WriteMessage(websocket.PingMessage, nil); err != nil {
log.Println(err)
return
}
}
}
}
func serveWebsocket(c *gin.Context) {
var err error
log.Println("websocket request")
conn, err = upgrader.Upgrade(c.Writer, c.Request, nil)
if err != nil {
if _, ok := err.(websocket.HandshakeError); !ok {
log.Printf("handshake error: %s", err)
}
log.Println(err)
return
}
go writer()
reader()
}