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package sendit
import (
"bufio"
"context"
"errors"
"io"
"log"
"net/http"
"net/http/httputil"
"net/url"
"path"
"strings"
"time"
"github.com/hashicorp/yamux"
)
func postWriter(ctx context.Context, urlStr string) (io.WriteCloser, error) {
pr, pw := io.Pipe()
req, err := http.NewRequest("POST", urlStr, pr)
if err != nil {
return nil, err
}
req.Header.Set("Transfer-Encoding", "chunked")
go func() {
resp, err := http.DefaultClient.Do(req.WithContext(ctx))
if err != nil {
pr.CloseWithError(err)
return
}
if resp.StatusCode != 200 {
pr.CloseWithError(errors.New("open write stream: " + resp.Status))
return
}
pr.Close()
}()
return pw, nil
}
func postReader(ctx context.Context, urlStr string) (io.ReadCloser, error) {
req, err := http.NewRequest("POST", urlStr, nil)
if err != nil {
return nil, err
}
req.Header.Set("Transfer-Encoding", "chunked")
resp, err := http.DefaultClient.Do(req.WithContext(ctx))
if err != nil {
return nil, err
}
if resp.StatusCode != 200 {
resp.Body.Close()
return nil, errors.New("open read stream: " + resp.Status)
}
return resp.Body, nil
}
// ConnectAndServe will connect to the server at `urlStr` and start serving/routing
// traffic to the local `addr`. If ttl > 0 then connections in each direction
// will be refreshed at the specified interval.
func ConnectAndServe(urlStr, dstURLStr, token string, ttl time.Duration) error {
dstU, err := url.Parse(dstURLStr)
if err != nil {
return err
}
u, err := url.Parse(urlStr)
if err != nil {
return err
}
serverPrefix, routePrefix := path.Split(u.Path)
u.Path = path.Join(serverPrefix, pathOpen)
v := make(url.Values)
v.Set("prefix", routePrefix)
v.Set("token", strings.TrimSpace(token))
resp, err := http.PostForm(u.String(), v)
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode != 200 {
return errors.New("Server Error: " + resp.Status)
}
r := bufio.NewReader(resp.Body)
tok, err := r.ReadString('\n')
if err != nil {
return err
}
v = make(url.Values)
v.Set("token", strings.TrimSpace(tok))
u.RawQuery = v.Encode()
stream := NewStream()
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
setPipe := func() error {
u.Path = path.Join(serverPrefix, pathClientRead)
reader, err := postReader(ctx, u.String())
if err != nil {
return err
}
u.Path = path.Join(serverPrefix, pathClientWrite)
writer, err := postWriter(ctx, u.String())
if err != nil {
_ = reader.Close()
return err
}
err = stream.SetPipe(reader, writer)
if err != nil {
reader.Close()
writer.Close()
return err
}
return nil
}
err = setPipe()
if err != nil {
return err
}
srv := &http.Server{
Handler: httputil.NewSingleHostReverseProxy(dstU),
}
go func() {
defer cancel()
defer func() { _ = stream.Close() }()
t := time.NewTicker(ttl)
defer t.Stop()
defer srv.Close()
for {
// check canceled first
select {
case <-ctx.Done():
return
default:
}
select {
case <-t.C:
err := setPipe()
if err != nil {
log.Println("ERROR: set pipe:", err)
return
}
case <-ctx.Done():
return
}
}
}()
cfg := yamux.DefaultConfig()
cfg.KeepAliveInterval = 3 * time.Second
sess, err := yamux.Client(stream, cfg)
if err != nil {
return err
}
defer sess.Close()
log.Printf("Ready; Forwarding %s -> %s", urlStr, dstURLStr)
return srv.Serve(sess)
}
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