Function accept

accept.go:106–182

(w http.ResponseWriter, r *http.Request, opts *AcceptOptions)

}

func accept(w http.ResponseWriter, r *http.Request, opts *AcceptOptions) (_ *Conn, err error) {
	defer errd.Wrap(&err, "failed to accept WebSocket connection")

	errCode, err := verifyClientRequest(w, r)
	if err != nil {
		http.Error(w, err.Error(), errCode)
		return nil, err
	}

	opts = opts.cloneWithDefaults()
	if !opts.InsecureSkipVerify {
		err = authenticateOrigin(r, opts.OriginPatterns)
		if err != nil {
			if errors.Is(err, path.ErrBadPattern) {
				log.Printf("websocket: %v", err)
				err = errors.New(http.StatusText(http.StatusForbidden))
			}
			http.Error(w, err.Error(), http.StatusForbidden)
			return nil, err
		}
	}

	hj, ok := hijacker(w)
	if !ok {
		err = errors.New("http.ResponseWriter does not implement http.Hijacker")
		http.Error(w, http.StatusText(http.StatusNotImplemented), http.StatusNotImplemented)
		return nil, err
	}

	w.Header().Set("Upgrade", "websocket")
	w.Header().Set("Connection", "Upgrade")

	key := r.Header.Get("Sec-WebSocket-Key")
	w.Header().Set("Sec-WebSocket-Accept", secWebSocketAccept(key))

	subproto := selectSubprotocol(r, opts.Subprotocols)
	if subproto != "" {
		w.Header().Set("Sec-WebSocket-Protocol", subproto)
	}

	copts, ok := selectDeflate(websocketExtensions(r.Header), opts.CompressionMode)
	if ok {
		w.Header().Set("Sec-WebSocket-Extensions", copts.String())
	}

	w.WriteHeader(http.StatusSwitchingProtocols)
	// See https://github.com/nhooyr/websocket/issues/166
	if ginWriter, ok := w.(interface {
		WriteHeaderNow()
	}); ok {
		ginWriter.WriteHeaderNow()
	}

	netConn, brw, err := hj.Hijack()
	if err != nil {
		err = fmt.Errorf("failed to hijack connection: %w", err)
		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		return nil, err