106 lines
2.2 KiB
Go
106 lines
2.2 KiB
Go
package websocket
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import (
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"bufio"
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"bytes"
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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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)
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var (
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ErrInvalidMethod = errors.New("Only GET Supported")
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ErrInvalidVersion = errors.New("Sec-Websocket-Version: 13")
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ErrInvalidUpgrade = errors.New("Can \"Upgrade\" only to \"WebSocket\"")
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ErrInvalidConnection = errors.New("\"Connection\" must be \"Upgrade\"")
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ErrMissingKey = errors.New("Missing Key")
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ErrHijacker = errors.New("Not implement http.Hijacker")
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ErrNoEmptyConn = errors.New("Conn ReadBuf must be empty")
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)
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func Upgrade(w http.ResponseWriter, r *http.Request, responseHeader http.Header) (*Conn, error) {
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if r.Method != "GET" {
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return nil, ErrInvalidMethod
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}
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if r.Header.Get("Sec-Websocket-Version") != "13" {
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return nil, ErrInvalidVersion
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}
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if strings.ToLower(r.Header.Get("Upgrade")) != "websocket" {
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return nil, ErrInvalidUpgrade
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}
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if strings.ToLower(r.Header.Get("Connection")) != "upgrade" {
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return nil, ErrInvalidConnection
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}
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var acceptKey string
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if key := r.Header.Get("Sec-Websocket-key"); len(key) == 0 {
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return nil, ErrMissingKey
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} else {
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acceptKey = calcAcceptKey(key)
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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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h, ok := w.(http.Hijacker)
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if !ok {
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return nil, ErrHijacker
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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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if br.Buffered() > 0 {
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netConn.Close()
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return nil, ErrNoEmptyConn
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}
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c := NewConn(netConn, true)
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buf := bytes.NewBufferString("HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: ")
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buf.WriteString(acceptKey)
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buf.WriteString("\r\n")
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subProtol := selectSubProtocol(r)
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if len(subProtol) > 0 {
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buf.WriteString("Sec-Websocket-Protocol: ")
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buf.WriteString(subProtol)
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buf.WriteString("\r\n")
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}
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for k, vs := range responseHeader {
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for _, v := range vs {
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buf.WriteString(k)
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buf.WriteString(": ")
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buf.WriteString(v)
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buf.WriteString("\r\n")
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}
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}
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buf.WriteString("\r\n")
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if _, err = netConn.Write(buf.Bytes()); err != nil {
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netConn.Close()
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return nil, err
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}
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return c, nil
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}
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func selectSubProtocol(r *http.Request) string {
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h := r.Header.Get("Sec-Websocket-Protocol")
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if len(h) == 0 {
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return ""
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}
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return strings.Split(h, ",")[0]
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}
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