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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package websocket
import (
"http"
"io"
)
/*
Handler is an interface to a WebSocket.
A trivial example server is:
package main
import (
"http"
"io"
"websocket"
)
// Echo the data received on the Web Socket.
func EchoServer(ws *websocket.Conn) {
io.Copy(ws, ws);
}
func main() {
http.Handle("/echo", websocket.Handler(EchoServer));
err := http.ListenAndServe(":12345", nil);
if err != nil {
panic("ListenAndServe: ", err.String())
}
}
*/
type Handler func(*Conn)
// ServeHTTP implements the http.Handler interface for a Web Socket.
func (f Handler) ServeHTTP(c *http.Conn, req *http.Request) {
if req.Method != "GET" || req.Proto != "HTTP/1.1" {
c.WriteHeader(http.StatusBadRequest)
io.WriteString(c, "Unexpected request")
return
}
if v, present := req.Header["Upgrade"]; !present || v != "WebSocket" {
c.WriteHeader(http.StatusBadRequest)
io.WriteString(c, "missing Upgrade: WebSocket header")
return
}
if v, present := req.Header["Connection"]; !present || v != "Upgrade" {
c.WriteHeader(http.StatusBadRequest)
io.WriteString(c, "missing Connection: Upgrade header")
return
}
origin, present := req.Header["Origin"]
if !present {
c.WriteHeader(http.StatusBadRequest)
io.WriteString(c, "missing Origin header")
return
}
rwc, buf, err := c.Hijack()
if err != nil {
panic("Hijack failed: ", err.String())
return
}
defer rwc.Close()
location := "ws://" + req.Host + req.URL.RawPath
// TODO(ukai): verify origin,location,protocol.
buf.WriteString("HTTP/1.1 101 Web Socket Protocol Handshake\r\n")
buf.WriteString("Upgrade: WebSocket\r\n")
buf.WriteString("Connection: Upgrade\r\n")
buf.WriteString("WebSocket-Origin: " + origin + "\r\n")
buf.WriteString("WebSocket-Location: " + location + "\r\n")
protocol, present := req.Header["Websocket-Protocol"]
// canonical header key of WebSocket-Protocol.
if present {
buf.WriteString("WebSocket-Protocol: " + protocol + "\r\n")
}
buf.WriteString("\r\n")
if err := buf.Flush(); err != nil {
return
}
ws := newConn(origin, location, protocol, buf, rwc)
f(ws)
}
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