115 lines
2.2 KiB
Go
115 lines
2.2 KiB
Go
// Package websocket provides WebSocket connectivity.
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package websocket
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import (
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"encoding/json"
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"fmt"
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"net"
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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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var (
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pingInterval = 30 * time.Second
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pingTimeout = 5 * time.Second
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writeTimeout = 2 * time.Second
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)
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var upgrader = websocket.Upgrader{
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CheckOrigin: func(r *http.Request) bool {
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return true
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},
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}
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// ServerConn is a server-side WebSocket connection with automatic, periodic ping / pong.
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type ServerConn struct {
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wc *websocket.Conn
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// in
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terminate chan struct{}
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write chan []byte
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// out
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writeErr chan error
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}
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// NewServerConn allocates a ServerConn.
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func NewServerConn(w http.ResponseWriter, req *http.Request) (*ServerConn, error) {
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wc, err := upgrader.Upgrade(w, req, nil)
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if err != nil {
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return nil, err
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}
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c := &ServerConn{
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wc: wc,
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terminate: make(chan struct{}),
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write: make(chan []byte),
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writeErr: make(chan error),
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}
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go c.run()
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return c, nil
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}
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// Close closes a ServerConn.
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func (c *ServerConn) Close() {
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c.wc.Close()
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close(c.terminate)
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}
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// RemoteAddr returns the remote address.
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func (c *ServerConn) RemoteAddr() net.Addr {
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return c.wc.RemoteAddr()
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}
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func (c *ServerConn) run() {
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c.wc.SetReadDeadline(time.Now().Add(pingInterval + pingTimeout))
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c.wc.SetPongHandler(func(string) error {
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c.wc.SetReadDeadline(time.Now().Add(pingInterval + pingTimeout))
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return nil
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})
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pingTicker := time.NewTicker(pingInterval)
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defer pingTicker.Stop()
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for {
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select {
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case byts := <-c.write:
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c.wc.SetWriteDeadline(time.Now().Add(writeTimeout))
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err := c.wc.WriteMessage(websocket.TextMessage, byts)
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c.writeErr <- err
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case <-pingTicker.C:
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c.wc.SetWriteDeadline(time.Now().Add(writeTimeout))
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c.wc.WriteMessage(websocket.PingMessage, nil)
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case <-c.terminate:
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return
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}
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}
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}
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// ReadJSON reads a JSON object.
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func (c *ServerConn) ReadJSON(in interface{}) error {
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return c.wc.ReadJSON(in)
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}
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// WriteJSON writes a JSON object.
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func (c *ServerConn) WriteJSON(in interface{}) error {
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byts, err := json.Marshal(in)
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if err != nil {
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return err
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}
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select {
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case c.write <- byts:
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return <-c.writeErr
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case <-c.terminate:
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return fmt.Errorf("terminated")
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}
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}
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