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@@ -5,8 +5,12 @@
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package websocket
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import (
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+ "bufio"
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+ "errors"
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+ "net"
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"net/http"
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"strings"
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+ "time"
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)
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// HandshakeError describes an error with the handshake from the peer.
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@@ -16,6 +20,181 @@ type HandshakeError struct {
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func (e HandshakeError) Error() string { return e.message }
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+const (
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+ DEFAULT_READ_BUFFER_SIZE = 4096
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+ DEFAULT_WRITE_BUFFER_SIZE = 4096
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+)
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+
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+type Upgrader struct {
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+ // HandshakeTimeout specifies the duration for the handshake to complete.
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+ HandshakeTimeout time.Duration
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+
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+ // Input and output buffer sizes. If the buffer size is zero, then
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+ // default values will be used.
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+ ReadBufferSize, WriteBufferSize int
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+
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+ // Subprotocols specifies the server's supported protocols. If Subprotocols
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+ // is nil, then Upgrade does not negotiate a subprotocol.
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+ Subprotocols []string
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+
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+ // Error specifies the function for generating HTTP error responses. If Error
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+ // is nil, then http.Error is used to generate the HTTP response.
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+ Error func(w http.ResponseWriter, r *http.Request, status int, reason error)
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+
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+ // CheckOrigin returns true if the request Origin header is acceptable.
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+ // If CheckOrigin is nil, then no origin check is done.
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+ CheckOrigin func(r *http.Request) bool
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+}
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+
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+// Return an error depending on settings on the Upgrader
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+func (u *Upgrader) returnError(w http.ResponseWriter, r *http.Request, status int, reason error) {
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+ if u.Error != nil {
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+ u.Error(w, r, status, reason)
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+ } else {
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+ http.Error(w, reason.Error(), status)
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+ }
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+}
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+
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+// Check if the passed subprotocol is supported by the server
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+func (u *Upgrader) hasSubprotocol(subprotocol string) bool {
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+ if u.Subprotocols == nil {
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+ return false
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+ }
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+
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+ for _, s := range u.Subprotocols {
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+ if s == subprotocol {
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+ return true
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+ }
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+ }
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+
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+ return false
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+}
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+
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+// Upgrade upgrades the HTTP server connection to the WebSocket protocol.
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+//
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+// The responseHeader is included in the response to the client's upgrade
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+// request. Use the responseHeader to specify cookies (Set-Cookie).
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+//
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+// The connection buffers IO to the underlying network connection.
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+// Messages can be larger than the buffers.
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+//
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+// If the request is not a valid WebSocket handshake, then Upgrade returns an
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+// error of type HandshakeError. Depending on settings on the Upgrader,
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+// an error message already has been returned to the caller.
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+func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeader http.Header) (*Conn, error) {
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+ if values := r.Header["Sec-Websocket-Version"]; len(values) == 0 || values[0] != "13" {
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+ err := HandshakeError{"websocket: version != 13"}
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+ u.returnError(w, r, http.StatusBadRequest, err)
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+ return nil, err
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+ }
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+
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+ if !tokenListContainsValue(r.Header, "Connection", "upgrade") {
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+ err := HandshakeError{"websocket: connection header != upgrade"}
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+ u.returnError(w, r, http.StatusBadRequest, err)
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+ return nil, err
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+ }
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+
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+ if !tokenListContainsValue(r.Header, "Upgrade", "websocket") {
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+ err := HandshakeError{"websocket: upgrade != websocket"}
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+ u.returnError(w, r, http.StatusBadRequest, err)
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+ return nil, err
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+ }
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+
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+ if u.CheckOrigin != nil && !u.CheckOrigin(r) {
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+ err := HandshakeError{"websocket: origin not allowed"}
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+ u.returnError(w, r, http.StatusForbidden, err)
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+ return nil, err
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+ }
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+
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+ var challengeKey string
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+ values := r.Header["Sec-Websocket-Key"]
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+ if len(values) == 0 || values[0] == "" {
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+ err := HandshakeError{"websocket: key missing or blank"}
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+ u.returnError(w, r, http.StatusBadRequest, err)
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+ return nil, err
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+ }
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+ challengeKey = values[0]
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+
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+ var (
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+ netConn net.Conn
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+ br *bufio.Reader
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+ err error
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+ )
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+
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+ h, ok := w.(http.Hijacker)
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+ if !ok {
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+ return nil, errors.New("websocket: response does not implement http.Hijacker")
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+ }
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+ var rw *bufio.ReadWriter
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+ netConn, rw, err = h.Hijack()
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+ br = rw.Reader
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+
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+ if br.Buffered() > 0 {
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+ netConn.Close()
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+ return nil, errors.New("websocket: client sent data before handshake is complete")
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+ }
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+
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+ readBufSize := u.ReadBufferSize
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+ if readBufSize == 0 {
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+ readBufSize = DEFAULT_READ_BUFFER_SIZE
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+ }
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+ writeBufSize := u.WriteBufferSize
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+ if writeBufSize == 0 {
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+ writeBufSize = DEFAULT_WRITE_BUFFER_SIZE
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+ }
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+ c := newConn(netConn, true, readBufSize, writeBufSize)
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+
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+ if u.Subprotocols != nil {
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+ for _, proto := range Subprotocols(r) {
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+ if u.hasSubprotocol(proto) {
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+ c.subprotocol = proto
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+ break
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+ }
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+ }
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+ } else if responseHeader != nil {
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+ c.subprotocol = responseHeader.Get("Sec-Websocket-Protocol")
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+ }
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+
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+ p := c.writeBuf[:0]
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+ p = append(p, "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: "...)
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+ p = append(p, computeAcceptKey(challengeKey)...)
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+ p = append(p, "\r\n"...)
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+ if c.subprotocol != "" {
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+ p = append(p, "Sec-Websocket-Protocol: "...)
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+ p = append(p, c.subprotocol...)
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+ p = append(p, "\r\n"...)
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+ }
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+ for k, vs := range responseHeader {
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+ if k == "Sec-Websocket-Protocol" {
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+ continue
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+ }
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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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+ for i := 0; i < len(v); i++ {
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+ b := v[i]
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+ if b <= 31 {
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+ // prevent response splitting.
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+ b = ' '
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+ }
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+ p = append(p, b)
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+ }
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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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+
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+ if u.HandshakeTimeout > 0 {
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+ netConn.SetWriteDeadline(time.Now().Add(u.HandshakeTimeout))
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+ }
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+ if _, err = netConn.Write(p); err != nil {
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+ netConn.Close()
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+ return nil, err
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+ }
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+
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+ return c, nil
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+}
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+
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// This method is deprecated, use websocket.Upgrader instead.
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//
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// Upgrade upgrades the HTTP server connection to the WebSocket protocol.
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Joachim Bauch