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main.go
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main.go
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package main
import (
"bufio"
"fmt"
"io"
"net/http"
"strings"
"sync"
"k8s.io/utils/env"
)
type myServerHandshaker struct {
UpgradeType *string
}
type ProtocolError struct{ ErrorString string }
func (err *ProtocolError) Error() string { return err.ErrorString }
var (
ErrBadRequestMethod = &ProtocolError{"bad method"}
ErrNotUpgrade = &ProtocolError{"not upgrade"}
)
func (c *myServerHandshaker) ReadHandshake(buf *bufio.Reader, req *http.Request) (code int, err error) {
upgradeType := req.Header.Get("Upgrade")
if strings.ToLower(upgradeType) == "" ||
!strings.Contains(strings.ToLower(req.Header.Get("Connection")), "upgrade") {
return http.StatusBadRequest, ErrNotUpgrade
}
c.UpgradeType = &upgradeType
return http.StatusSwitchingProtocols, nil
}
func (c *myServerHandshaker) AcceptHandshake(buf *bufio.Writer, resp *http.Response) (err error) {
buf.WriteString("HTTP/1.1 101 Switching Protocols\r\n")
// Rely on Upgrade & Connection headers from copied response headers
for headerName, headerValues := range resp.Header {
for _, headerValue := range headerValues {
buf.WriteString(headerName + ": " + headerValue + "\r\n")
}
}
buf.WriteString("\r\n")
return buf.Flush()
}
type serverHandshaker interface {
ReadHandshake(buf *bufio.Reader, req *http.Request) (code int, err error)
AcceptHandshake(buf *bufio.Writer, resp *http.Response) (err error)
}
func newServerConn(inrwc io.ReadWriteCloser, inbuf *bufio.ReadWriter, inreq *http.Request) (err error) {
fmt.Println("> [" + inreq.Method + "]" + inreq.URL.String())
upgradeType := ""
var hs serverHandshaker = &myServerHandshaker{UpgradeType: &upgradeType}
_, hserr := hs.ReadHandshake(inbuf.Reader, inreq)
var outreq *http.Request
url := env.GetString("API_SERVER", "") + inreq.URL.String()
outreq, err = http.NewRequest(inreq.Method, url, nil)
if err != nil {
return
}
outreq.Header = inreq.Header.Clone()
outreq.SetBasicAuth(env.GetString("USERNAME", ""), env.GetString("PASSWORD", ""))
var outresp *http.Response
isUpgrade := hserr != ErrNotUpgrade
if !isUpgrade {
outresp, err = http.DefaultClient.Do(outreq)
if err != nil {
fmt.Println("Error in do:" + err.Error())
return
}
fmt.Println("< [" + outresp.Status + "]" + inreq.URL.String())
outresp.Write(inbuf)
inbuf.Flush()
return
}
fmt.Println("Inbound upgrade request. type=" + upgradeType + " url:" + inreq.URL.String())
roundTripper := NewUpgradeRoundTripper(nil, true, false, upgradeType)
outresp, err = roundTripper.RoundTrip(outreq)
if err != nil {
fmt.Println("Error in do:" + err.Error())
return
}
fmt.Println("Outbound upgrade requested. url:" + inreq.URL.String())
outConn, err := roundTripper.NewConnection(outresp)
if err != nil {
fmt.Println("Error in NewConnection:" + err.Error())
return
}
fmt.Println("Outbound upgrade accepted. url:" + inreq.URL.String())
//Acccept inbbound
err = hs.AcceptHandshake(inbuf.Writer, outresp)
if err != nil {
code := http.StatusBadRequest
fmt.Fprintf(inbuf, "HTTP/1.1 %03d %s\r\n", code, http.StatusText(code))
inbuf.WriteString("\r\n")
inbuf.Flush()
return
}
fmt.Println("Inbound upgrade accepted. url:" + inreq.URL.String())
var allComplete sync.WaitGroup
allComplete.Add(2)
var anyComplete sync.Mutex
anyComplete.Lock()
go func() {
io.Copy(outConn, inrwc)
fmt.Println("Copy in to out complete. url:" + inreq.URL.String())
anyComplete.Unlock()
allComplete.Done()
}()
go func() {
io.Copy(inrwc, outConn)
fmt.Println("Copy out to in complete. url:" + inreq.URL.String())
anyComplete.Unlock()
allComplete.Done()
}()
anyComplete.Lock()
fmt.Println("Calling close on in+out. url:" + inreq.URL.String())
outConn.Close()
inrwc.Close()
fmt.Println("Calling close on in+out complete. url:" + inreq.URL.String())
allComplete.Wait()
fmt.Println("Copy out <-> in complete. url:" + inreq.URL.String())
fmt.Println("Handling done. url:" + inreq.URL.String())
return
}
func serveUpgrade(w http.ResponseWriter, req *http.Request) {
rwc, buf, err := w.(http.Hijacker).Hijack()
if err != nil {
panic("Hijack failed: " + err.Error())
}
// The server should abort the WebSocket connection if it finds
// the client did not send a handshake that matches with protocol
// specification.
defer rwc.Close()
err = newServerConn(rwc, buf, req)
if err != nil {
return
}
}
func main() {
http.HandleFunc("/", serveUpgrade)
err := http.ListenAndServe(env.GetString("LISTEN_ADDR", ":12345"), nil)
if err != nil {
panic("ListenAndServe: " + err.Error())
}
}