113 lines
3.4 KiB
Go
113 lines
3.4 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package websocket
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import (
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"bufio"
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"fmt"
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"io"
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"net/http"
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)
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func newServerConn(rwc io.ReadWriteCloser, buf *bufio.ReadWriter, req *http.Request, config *Config, handshake func(*Config, *http.Request) error) (conn *Conn, err error) {
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var hs serverHandshaker = &hybiServerHandshaker{Config: config}
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code, err := hs.ReadHandshake(buf.Reader, req)
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if err == ErrBadWebSocketVersion {
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fmt.Fprintf(buf, "HTTP/1.1 %03d %s\r\n", code, http.StatusText(code))
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fmt.Fprintf(buf, "Sec-WebSocket-Version: %s\r\n", SupportedProtocolVersion)
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buf.WriteString("\r\n")
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buf.WriteString(err.Error())
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buf.Flush()
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return
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}
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if err != nil {
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fmt.Fprintf(buf, "HTTP/1.1 %03d %s\r\n", code, http.StatusText(code))
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buf.WriteString("\r\n")
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buf.WriteString(err.Error())
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buf.Flush()
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return
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}
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if handshake != nil {
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err = handshake(config, req)
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if err != nil {
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code = http.StatusForbidden
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fmt.Fprintf(buf, "HTTP/1.1 %03d %s\r\n", code, http.StatusText(code))
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buf.WriteString("\r\n")
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buf.Flush()
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return
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}
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}
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err = hs.AcceptHandshake(buf.Writer)
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if err != nil {
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code = http.StatusBadRequest
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fmt.Fprintf(buf, "HTTP/1.1 %03d %s\r\n", code, http.StatusText(code))
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buf.WriteString("\r\n")
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buf.Flush()
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return
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}
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conn = hs.NewServerConn(buf, rwc, req)
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return
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}
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// Server represents a server of a WebSocket.
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type Server struct {
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// Config is a WebSocket configuration for new WebSocket connection.
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Config
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// Handshake is an optional function in WebSocket handshake.
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// For example, you can check, or don't check Origin header.
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// Another example, you can select config.Protocol.
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Handshake func(*Config, *http.Request) error
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// Handler handles a WebSocket connection.
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Handler
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}
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// ServeHTTP implements the http.Handler interface for a WebSocket
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func (s Server) ServeHTTP(w http.ResponseWriter, req *http.Request) {
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s.serveWebSocket(w, req)
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}
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func (s Server) serveWebSocket(w http.ResponseWriter, req *http.Request) {
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rwc, buf, err := w.(http.Hijacker).Hijack()
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if err != nil {
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panic("Hijack failed: " + err.Error())
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}
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// The server should abort the WebSocket connection if it finds
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// the client did not send a handshake that matches with protocol
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// specification.
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defer rwc.Close()
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conn, err := newServerConn(rwc, buf, req, &s.Config, s.Handshake)
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if err != nil {
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return
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}
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if conn == nil {
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panic("unexpected nil conn")
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}
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s.Handler(conn)
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}
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// Handler is a simple interface to a WebSocket browser client.
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// It checks if Origin header is valid URL by default.
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// You might want to verify websocket.Conn.Config().Origin in the func.
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// If you use Server instead of Handler, you could call websocket.Origin and
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// check the origin in your Handshake func. So, if you want to accept
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// non-browser clients, which do not send an Origin header, set a
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// Server.Handshake that does not check the origin.
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type Handler func(*Conn)
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func checkOrigin(config *Config, req *http.Request) (err error) {
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config.Origin, err = Origin(config, req)
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if err == nil && config.Origin == nil {
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return fmt.Errorf("null origin")
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}
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return err
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}
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// ServeHTTP implements the http.Handler interface for a WebSocket
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func (h Handler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
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s := Server{Handler: h, Handshake: checkOrigin}
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s.serveWebSocket(w, req)
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}
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