91 lines
2.1 KiB
Go
91 lines
2.1 KiB
Go
package websocket
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import (
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"log"
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"net/http"
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"time"
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"github.com/gorilla/websocket"
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)
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const (
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// Time allowed to write a message to the peer.
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writeWait = 10 * time.Second
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// Time allowed to read the next pong message from the peer.
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pongWait = 60 * time.Second
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// Send pings to peer with this period. Must be less than pongWait.
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pingPeriod = (pongWait * 9) / 10
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)
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var upgrader = websocket.Upgrader{
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ReadBufferSize: 1024,
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WriteBufferSize: 1024,
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}
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// ClientHandler is a middleman between the websocket connection and the hub.
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type ClientHandler struct {
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hub *Hub
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// The websocket connection.
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conn *websocket.Conn
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// Buffered channel of outbound messages.
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send chan []byte
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}
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// writePump pumps messages from the hub to the websocket connection.
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//
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// A goroutine running writePump is started for each connection. The
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// application ensures that there is at most one writer to a connection by
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// executing all writes from this goroutine.
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func (c *ClientHandler) writePump() {
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ticker := time.NewTicker(pingPeriod)
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defer func() {
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ticker.Stop()
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c.conn.Close()
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}()
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for {
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select {
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case message, ok := <-c.send:
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_ = c.conn.SetWriteDeadline(time.Now().Add(writeWait))
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if !ok {
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// The hub closed the channel.
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_ = c.conn.WriteMessage(websocket.CloseMessage, []byte{})
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return
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}
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w, err := c.conn.NextWriter(websocket.TextMessage)
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if err != nil {
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return
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}
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_, _ = w.Write(message)
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if err := w.Close(); err != nil {
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return
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}
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case <-ticker.C:
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_ = c.conn.SetWriteDeadline(time.Now().Add(writeWait))
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if err := c.conn.WriteMessage(websocket.PingMessage, nil); err != nil {
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return
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}
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}
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}
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}
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// ServeWs handles websocket requests from the peer.
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func (h *Hub) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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conn, err := upgrader.Upgrade(w, r, nil)
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if err != nil {
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log.Println(err)
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return
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}
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client := &ClientHandler{hub: h, conn: conn, send: make(chan []byte, 256)}
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client.hub.register <- client
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// Allow collection of memory referenced by the caller by doing all work in
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// new goroutines.
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go client.writePump()
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}
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