astraproxy/utils.go

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package main
import (
"context"
"net"
"sync"
"io"
"time"
"errors"
"net/http"
"bufio"
)
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const COPY_BUF = 128 * 1024
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func proxy(ctx context.Context, left, right net.Conn) {
wg := sync.WaitGroup{}
cpy := func (dst, src net.Conn) {
defer wg.Done()
io.Copy(dst, src)
dst.Close()
}
wg.Add(2)
go cpy(left, right)
go cpy(right, left)
groupdone := make(chan struct{}, 1)
go func() {
wg.Wait()
groupdone <-struct{}{}
}()
select {
case <-ctx.Done():
left.Close()
right.Close()
case <-groupdone:
return
}
<-groupdone
return
}
// Hop-by-hop headers. These are removed when sent to the backend.
// http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
var hopHeaders = []string{
"Connection",
"Keep-Alive",
"Proxy-Authenticate",
"Proxy-Connection",
"Proxy-Authorization",
"Te", // canonicalized version of "TE"
"Trailers",
"Transfer-Encoding",
"Upgrade",
}
func copyHeader(dst, src http.Header) {
for k, vv := range src {
for _, v := range vv {
dst.Add(k, v)
}
}
}
func delHopHeaders(header http.Header) {
for _, h := range hopHeaders {
header.Del(h)
}
}
func hijack(hijackable interface{}) (net.Conn, *bufio.ReadWriter, error) {
hj, ok := hijackable.(http.Hijacker)
if !ok {
return nil, nil, errors.New("Connection doesn't support hijacking")
}
conn, rw, err := hj.Hijack()
if err != nil {
return nil, nil, err
}
var emptytime time.Time
err = conn.SetDeadline(emptytime)
if err != nil {
conn.Close()
return nil, nil, err
}
return conn, rw, nil
}
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func flush(flusher interface{}) bool {
f, ok := flusher.(http.Flusher)
if !ok {
return false
}
f.Flush()
return true
}
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func copyBody(wr io.Writer, body io.Reader) {
for {
buf := make([]byte, COPY_BUF)
bread, read_err := body.Read(buf)
var write_err error
if bread > 0 {
_, write_err = wr.Write(buf[:bread])
flush(wr)
}
if read_err != nil || write_err != nil {
break
}
}
}