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259928ab62
if we recognize that a request for a WebForward is trying to turn the connection into a websocket, we forward it to the backend and check if the backend understands the websocket request. if so, we pass back the upgrade response and get out of the way, copying bytes between the two. we do log the total amount of bytes read from the client and written to the client. if the backend doesn't respond with a websocke response, or an invalid one, we respond with a regular non-websocket response. and we log details about the failed connection, should help with debugging and any bug reports. we don't try to parse the websocket framing, that's between the client and the backend. we could try to parse it, in part to protect the backend from bad frames, but it would be a lot of work and could be brittle in the face of extensions. this doesn't yet handle websocket connections when a http proxy is configured. we'll implement it when someone needs it. we do recognize it and fail the connection. for issue #25
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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