HTTP proxy written in Go to replace Tinyproxy (#269)

internal/httpproxy/https.go

@@ -0,0 +1,64 @@
+package httpproxy
+
+import (
+	"context"
+	"io"
+	"net"
+	"net/http"
+	"sync"
+)
+
+func (h *handler) handleHTTPS(responseWriter http.ResponseWriter, request *http.Request) {
+	dialer := net.Dialer{Timeout: h.relayTimeout}
+	destinationConn, err := dialer.DialContext(h.ctx, "tcp", request.Host)
+	if err != nil {
+		http.Error(responseWriter, err.Error(), http.StatusServiceUnavailable)
+		return
+	}
+
+	responseWriter.WriteHeader(http.StatusOK)
+
+	hijacker, ok := responseWriter.(http.Hijacker)
+	if !ok {
+		http.Error(responseWriter, "Hijacking not supported", http.StatusInternalServerError)
+		return
+	}
+	clientConnection, _, err := hijacker.Hijack()
+	if err != nil {
+		h.logger.Warn(err)
+		http.Error(responseWriter, err.Error(), http.StatusServiceUnavailable)
+		if err := destinationConn.Close(); err != nil {
+			h.logger.Error("closing destination connection: %s", err)
+		}
+		return
+	}
+
+	if h.verbose {
+		h.logger.Info("%s <-> %s", request.RemoteAddr, request.Host)
+	}
+
+	h.wg.Add(1)
+	ctx, cancel := context.WithCancel(h.ctx)
+	const transferGoroutines = 2
+	wg := &sync.WaitGroup{}
+	wg.Add(transferGoroutines)
+	go func() { // trigger cleanup when done
+		wg.Wait()
+		cancel()
+	}()
+	go func() { // cleanup
+		<-ctx.Done()
+		destinationConn.Close()
+		clientConnection.Close()
+		h.wg.Done()
+	}()
+	go transfer(destinationConn, clientConnection, wg)
+	go transfer(clientConnection, destinationConn, wg)
+}
+
+func transfer(destination io.WriteCloser, source io.ReadCloser, wg *sync.WaitGroup) {
+	_, _ = io.Copy(destination, source)
+	_ = source.Close()
+	_ = destination.Close()
+	wg.Done()
+}