gtsocial-umbx

client.go (12681B)

---

 // Copyright 2013 The Gorilla WebSocket 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 (
 	"bytes"
 	"context"
 	"crypto/tls"
 	"errors"
 	"io"
 	"io/ioutil"
 	"net"
 	"net/http"
 	"net/http/httptrace"
 	"net/url"
 	"strings"
 	"time"
 )
 
 // ErrBadHandshake is returned when the server response to opening handshake is
 // invalid.
 var ErrBadHandshake = errors.New("websocket: bad handshake")
 
 var errInvalidCompression = errors.New("websocket: invalid compression negotiation")
 
 // NewClient creates a new client connection using the given net connection.
 // The URL u specifies the host and request URI. Use requestHeader to specify
 // the origin (Origin), subprotocols (Sec-WebSocket-Protocol) and cookies
 // (Cookie). Use the response.Header to get the selected subprotocol
 // (Sec-WebSocket-Protocol) and cookies (Set-Cookie).
 //
 // If the WebSocket handshake fails, ErrBadHandshake is returned along with a
 // non-nil *http.Response so that callers can handle redirects, authentication,
 // etc.
 //
 // Deprecated: Use Dialer instead.
 func NewClient(netConn net.Conn, u *url.URL, requestHeader http.Header, readBufSize, writeBufSize int) (c *Conn, response *http.Response, err error) {
 	d := Dialer{
 		ReadBufferSize:  readBufSize,
 		WriteBufferSize: writeBufSize,
 		NetDial: func(net, addr string) (net.Conn, error) {
 			return netConn, nil
 		},
 	}
 	return d.Dial(u.String(), requestHeader)
 }
 
 // A Dialer contains options for connecting to WebSocket server.
 //
 // It is safe to call Dialer's methods concurrently.
 type Dialer struct {
 	// NetDial specifies the dial function for creating TCP connections. If
 	// NetDial is nil, net.Dial is used.
 	NetDial func(network, addr string) (net.Conn, error)
 
 	// NetDialContext specifies the dial function for creating TCP connections. If
 	// NetDialContext is nil, NetDial is used.
 	NetDialContext func(ctx context.Context, network, addr string) (net.Conn, error)
 
 	// NetDialTLSContext specifies the dial function for creating TLS/TCP connections. If
 	// NetDialTLSContext is nil, NetDialContext is used.
 	// If NetDialTLSContext is set, Dial assumes the TLS handshake is done there and
 	// TLSClientConfig is ignored.
 	NetDialTLSContext func(ctx context.Context, network, addr string) (net.Conn, error)
 
 	// Proxy specifies a function to return a proxy for a given
 	// Request. If the function returns a non-nil error, the
 	// request is aborted with the provided error.
 	// If Proxy is nil or returns a nil *URL, no proxy is used.
 	Proxy func(*http.Request) (*url.URL, error)
 
 	// TLSClientConfig specifies the TLS configuration to use with tls.Client.
 	// If nil, the default configuration is used.
 	// If either NetDialTLS or NetDialTLSContext are set, Dial assumes the TLS handshake
 	// is done there and TLSClientConfig is ignored.
 	TLSClientConfig *tls.Config
 
 	// HandshakeTimeout specifies the duration for the handshake to complete.
 	HandshakeTimeout time.Duration
 
 	// ReadBufferSize and WriteBufferSize specify I/O buffer sizes in bytes. If a buffer
 	// size is zero, then a useful default size is used. The I/O buffer sizes
 	// do not limit the size of the messages that can be sent or received.
 	ReadBufferSize, WriteBufferSize int
 
 	// WriteBufferPool is a pool of buffers for write operations. If the value
 	// is not set, then write buffers are allocated to the connection for the
 	// lifetime of the connection.
 	//
 	// A pool is most useful when the application has a modest volume of writes
 	// across a large number of connections.
 	//
 	// Applications should use a single pool for each unique value of
 	// WriteBufferSize.
 	WriteBufferPool BufferPool
 
 	// Subprotocols specifies the client's requested subprotocols.
 	Subprotocols []string
 
 	// EnableCompression specifies if the client should attempt to negotiate
 	// per message compression (RFC 7692). Setting this value to true does not
 	// guarantee that compression will be supported. Currently only "no context
 	// takeover" modes are supported.
 	EnableCompression bool
 
 	// Jar specifies the cookie jar.
 	// If Jar is nil, cookies are not sent in requests and ignored
 	// in responses.
 	Jar http.CookieJar
 }
 
 // Dial creates a new client connection by calling DialContext with a background context.
 func (d *Dialer) Dial(urlStr string, requestHeader http.Header) (*Conn, *http.Response, error) {
 	return d.DialContext(context.Background(), urlStr, requestHeader)
 }
 
 var errMalformedURL = errors.New("malformed ws or wss URL")
 
 func hostPortNoPort(u *url.URL) (hostPort, hostNoPort string) {
 	hostPort = u.Host
 	hostNoPort = u.Host
 	if i := strings.LastIndex(u.Host, ":"); i > strings.LastIndex(u.Host, "]") {
 		hostNoPort = hostNoPort[:i]
 	} else {
 		switch u.Scheme {
 		case "wss":
 			hostPort += ":443"
 		case "https":
 			hostPort += ":443"
 		default:
 			hostPort += ":80"
 		}
 	}
 	return hostPort, hostNoPort
 }
 
 // DefaultDialer is a dialer with all fields set to the default values.
 var DefaultDialer = &Dialer{
 	Proxy:            http.ProxyFromEnvironment,
 	HandshakeTimeout: 45 * time.Second,
 }
 
 // nilDialer is dialer to use when receiver is nil.
 var nilDialer = *DefaultDialer
 
 // DialContext creates a new client connection. Use requestHeader to specify the
 // origin (Origin), subprotocols (Sec-WebSocket-Protocol) and cookies (Cookie).
 // Use the response.Header to get the selected subprotocol
 // (Sec-WebSocket-Protocol) and cookies (Set-Cookie).
 //
 // The context will be used in the request and in the Dialer.
 //
 // If the WebSocket handshake fails, ErrBadHandshake is returned along with a
 // non-nil *http.Response so that callers can handle redirects, authentication,
 // etcetera. The response body may not contain the entire response and does not
 // need to be closed by the application.
 func (d *Dialer) DialContext(ctx context.Context, urlStr string, requestHeader http.Header) (*Conn, *http.Response, error) {
 	if d == nil {
 		d = &nilDialer
 	}
 
 	challengeKey, err := generateChallengeKey()
 	if err != nil {
 		return nil, nil, err
 	}
 
 	u, err := url.Parse(urlStr)
 	if err != nil {
 		return nil, nil, err
 	}
 
 	switch u.Scheme {
 	case "ws":
 		u.Scheme = "http"
 	case "wss":
 		u.Scheme = "https"
 	default:
 		return nil, nil, errMalformedURL
 	}
 
 	if u.User != nil {
 		// User name and password are not allowed in websocket URIs.
 		return nil, nil, errMalformedURL
 	}
 
 	req := &http.Request{
 		Method:     http.MethodGet,
 		URL:        u,
 		Proto:      "HTTP/1.1",
 		ProtoMajor: 1,
 		ProtoMinor: 1,
 		Header:     make(http.Header),
 		Host:       u.Host,
 	}
 	req = req.WithContext(ctx)
 
 	// Set the cookies present in the cookie jar of the dialer
 	if d.Jar != nil {
 		for _, cookie := range d.Jar.Cookies(u) {
 			req.AddCookie(cookie)
 		}
 	}
 
 	// Set the request headers using the capitalization for names and values in
 	// RFC examples. Although the capitalization shouldn't matter, there are
 	// servers that depend on it. The Header.Set method is not used because the
 	// method canonicalizes the header names.
 	req.Header["Upgrade"] = []string{"websocket"}
 	req.Header["Connection"] = []string{"Upgrade"}
 	req.Header["Sec-WebSocket-Key"] = []string{challengeKey}
 	req.Header["Sec-WebSocket-Version"] = []string{"13"}
 	if len(d.Subprotocols) > 0 {
 		req.Header["Sec-WebSocket-Protocol"] = []string{strings.Join(d.Subprotocols, ", ")}
 	}
 	for k, vs := range requestHeader {
 		switch {
 		case k == "Host":
 			if len(vs) > 0 {
 				req.Host = vs[0]
 			}
 		case k == "Upgrade" ||
 			k == "Connection" ||
 			k == "Sec-Websocket-Key" ||
 			k == "Sec-Websocket-Version" ||
 			k == "Sec-Websocket-Extensions" ||
 			(k == "Sec-Websocket-Protocol" && len(d.Subprotocols) > 0):
 			return nil, nil, errors.New("websocket: duplicate header not allowed: " + k)
 		case k == "Sec-Websocket-Protocol":
 			req.Header["Sec-WebSocket-Protocol"] = vs
 		default:
 			req.Header[k] = vs
 		}
 	}
 
 	if d.EnableCompression {
 		req.Header["Sec-WebSocket-Extensions"] = []string{"permessage-deflate; server_no_context_takeover; client_no_context_takeover"}
 	}
 
 	if d.HandshakeTimeout != 0 {
 		var cancel func()
 		ctx, cancel = context.WithTimeout(ctx, d.HandshakeTimeout)
 		defer cancel()
 	}
 
 	// Get network dial function.
 	var netDial func(network, add string) (net.Conn, error)
 
 	switch u.Scheme {
 	case "http":
 		if d.NetDialContext != nil {
 			netDial = func(network, addr string) (net.Conn, error) {
 				return d.NetDialContext(ctx, network, addr)
 			}
 		} else if d.NetDial != nil {
 			netDial = d.NetDial
 		}
 	case "https":
 		if d.NetDialTLSContext != nil {
 			netDial = func(network, addr string) (net.Conn, error) {
 				return d.NetDialTLSContext(ctx, network, addr)
 			}
 		} else if d.NetDialContext != nil {
 			netDial = func(network, addr string) (net.Conn, error) {
 				return d.NetDialContext(ctx, network, addr)
 			}
 		} else if d.NetDial != nil {
 			netDial = d.NetDial
 		}
 	default:
 		return nil, nil, errMalformedURL
 	}
 
 	if netDial == nil {
 		netDialer := &net.Dialer{}
 		netDial = func(network, addr string) (net.Conn, error) {
 			return netDialer.DialContext(ctx, network, addr)
 		}
 	}
 
 	// If needed, wrap the dial function to set the connection deadline.
 	if deadline, ok := ctx.Deadline(); ok {
 		forwardDial := netDial
 		netDial = func(network, addr string) (net.Conn, error) {
 			c, err := forwardDial(network, addr)
 			if err != nil {
 				return nil, err
 			}
 			err = c.SetDeadline(deadline)
 			if err != nil {
 				c.Close()
 				return nil, err
 			}
 			return c, nil
 		}
 	}
 
 	// If needed, wrap the dial function to connect through a proxy.
 	if d.Proxy != nil {
 		proxyURL, err := d.Proxy(req)
 		if err != nil {
 			return nil, nil, err
 		}
 		if proxyURL != nil {
 			dialer, err := proxy_FromURL(proxyURL, netDialerFunc(netDial))
 			if err != nil {
 				return nil, nil, err
 			}
 			netDial = dialer.Dial
 		}
 	}
 
 	hostPort, hostNoPort := hostPortNoPort(u)
 	trace := httptrace.ContextClientTrace(ctx)
 	if trace != nil && trace.GetConn != nil {
 		trace.GetConn(hostPort)
 	}
 
 	netConn, err := netDial("tcp", hostPort)
 	if trace != nil && trace.GotConn != nil {
 		trace.GotConn(httptrace.GotConnInfo{
 			Conn: netConn,
 		})
 	}
 	if err != nil {
 		return nil, nil, err
 	}
 
 	defer func() {
 		if netConn != nil {
 			netConn.Close()
 		}
 	}()
 
 	if u.Scheme == "https" && d.NetDialTLSContext == nil {
 		// If NetDialTLSContext is set, assume that the TLS handshake has already been done
 
 		cfg := cloneTLSConfig(d.TLSClientConfig)
 		if cfg.ServerName == "" {
 			cfg.ServerName = hostNoPort
 		}
 		tlsConn := tls.Client(netConn, cfg)
 		netConn = tlsConn
 
 		if trace != nil && trace.TLSHandshakeStart != nil {
 			trace.TLSHandshakeStart()
 		}
 		err := doHandshake(ctx, tlsConn, cfg)
 		if trace != nil && trace.TLSHandshakeDone != nil {
 			trace.TLSHandshakeDone(tlsConn.ConnectionState(), err)
 		}
 
 		if err != nil {
 			return nil, nil, err
 		}
 	}
 
 	conn := newConn(netConn, false, d.ReadBufferSize, d.WriteBufferSize, d.WriteBufferPool, nil, nil)
 
 	if err := req.Write(netConn); err != nil {
 		return nil, nil, err
 	}
 
 	if trace != nil && trace.GotFirstResponseByte != nil {
 		if peek, err := conn.br.Peek(1); err == nil && len(peek) == 1 {
 			trace.GotFirstResponseByte()
 		}
 	}
 
 	resp, err := http.ReadResponse(conn.br, req)
 	if err != nil {
 		return nil, nil, err
 	}
 
 	if d.Jar != nil {
 		if rc := resp.Cookies(); len(rc) > 0 {
 			d.Jar.SetCookies(u, rc)
 		}
 	}
 
 	if resp.StatusCode != 101 ||
 		!tokenListContainsValue(resp.Header, "Upgrade", "websocket") ||
 		!tokenListContainsValue(resp.Header, "Connection", "upgrade") ||
 		resp.Header.Get("Sec-Websocket-Accept") != computeAcceptKey(challengeKey) {
 		// Before closing the network connection on return from this
 		// function, slurp up some of the response to aid application
 		// debugging.
 		buf := make([]byte, 1024)
 		n, _ := io.ReadFull(resp.Body, buf)
 		resp.Body = ioutil.NopCloser(bytes.NewReader(buf[:n]))
 		return nil, resp, ErrBadHandshake
 	}
 
 	for _, ext := range parseExtensions(resp.Header) {
 		if ext[""] != "permessage-deflate" {
 			continue
 		}
 		_, snct := ext["server_no_context_takeover"]
 		_, cnct := ext["client_no_context_takeover"]
 		if !snct || !cnct {
 			return nil, resp, errInvalidCompression
 		}
 		conn.newCompressionWriter = compressNoContextTakeover
 		conn.newDecompressionReader = decompressNoContextTakeover
 		break
 	}
 
 	resp.Body = ioutil.NopCloser(bytes.NewReader([]byte{}))
 	conn.subprotocol = resp.Header.Get("Sec-Websocket-Protocol")
 
 	netConn.SetDeadline(time.Time{})
 	netConn = nil // to avoid close in defer.
 	return conn, resp, nil
 }
 
 func cloneTLSConfig(cfg *tls.Config) *tls.Config {
 	if cfg == nil {
 		return &tls.Config{}
 	}
 	return cfg.Clone()
 }