mirror of https://github.com/gorilla/websocket.git
70 lines
2.2 KiB
Go
70 lines
2.2 KiB
Go
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// Copyright 2013 Gary Burd. 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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"errors"
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"net"
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"net/http"
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"net/url"
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"strings"
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)
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// ErrBadHandshake is returned when the server response to opening handshake is
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// invalid.
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var ErrBadHandshake = errors.New("websocket: bad handshake")
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// NewClient creates a new client connection using the given net connection.
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// The URL u specifies the host and request URI. Use requestHeader to specify
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// the origin (Origin), subprotocols (Set-WebSocket-Protocol) and cookies
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// (Cookie). Use the response.Header to get the selected subprotocol
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// (Sec-WebSocket-Protocol) and cookies (Set-Cookie).
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//
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// If the WebSocket handshake fails, ErrBadHandshake is returned along with a
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// non-nil *http.Response so that callers can handle redirects, authentication,
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// etc.
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func NewClient(netConn net.Conn, u *url.URL, requestHeader http.Header, readBufSize, writeBufSize int) (c *Conn, response *http.Response, err error) {
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challengeKey, err := generateChallengeKey()
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if err != nil {
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return nil, nil, err
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}
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acceptKey := computeAcceptKey(challengeKey)
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c = newConn(netConn, false, readBufSize, writeBufSize)
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p := c.writeBuf[:0]
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p = append(p, "GET "...)
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p = append(p, u.RequestURI()...)
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p = append(p, " HTTP/1.1\r\nHost: "...)
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p = append(p, u.Host...)
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p = append(p, "\r\nUpgrade: websocket\r\nConnection: upgrade\r\nSec-WebSocket-Version: 13\r\nSec-WebSocket-Key: "...)
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p = append(p, challengeKey...)
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p = append(p, "\r\n"...)
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for k, vs := range requestHeader {
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for _, v := range vs {
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p = append(p, k...)
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p = append(p, ": "...)
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p = append(p, v...)
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p = append(p, "\r\n"...)
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}
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}
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p = append(p, "\r\n"...)
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if _, err := netConn.Write(p); err != nil {
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return nil, nil, err
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}
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resp, err := http.ReadResponse(c.br, &http.Request{Method: "GET", URL: u})
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if err != nil {
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return nil, nil, err
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}
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if resp.StatusCode != 101 ||
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!strings.EqualFold(resp.Header.Get("Upgrade"), "websocket") ||
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!strings.EqualFold(resp.Header.Get("Connection"), "upgrade") ||
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resp.Header.Get("Sec-Websocket-Accept") != acceptKey {
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return nil, resp, ErrBadHandshake
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}
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return c, resp, nil
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}
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