Add comprehensive debug logging to forwardHTTPRequest

- Add logging for URL construction and target resolution
- Log HTTP client request creation and execution
- Track response reception and body copying
- Helps diagnose 'Empty reply from server' issue in privileged mode
- No functional changes, only improved observability

Co-authored-by: f0ssel <[email protected]>

Author: blink-so[bot]

proxy/proxy.go

@@ -183,6 +183,8 @@ func (p *Server) handleHTTPS(w http.ResponseWriter, r *http.Request) {
 
 // forwardHTTPRequest forwards a regular HTTP request
 func (p *Server) forwardHTTPRequest(w http.ResponseWriter, r *http.Request) {
+	p.logger.Debug("forwardHTTPRequest called", "method", r.Method, "url", r.URL.String(), "host", r.Host)
+	
 	// Create a new request to the target server
 	targetURL := r.URL
 	if targetURL.Scheme == "" {
@@ -192,6 +194,8 @@ func (p *Server) forwardHTTPRequest(w http.ResponseWriter, r *http.Request) {
 		targetURL.Host = r.Host
 	}
 
+	p.logger.Debug("Target URL constructed", "target", targetURL.String())
+
 	// Create HTTP client
 	client := &http.Client{
 		CheckRedirect: func(req *http.Request, via []*http.Request) error {
@@ -202,6 +206,7 @@ func (p *Server) forwardHTTPRequest(w http.ResponseWriter, r *http.Request) {
 	// Create new request
 	req, err := http.NewRequest(r.Method, targetURL.String(), r.Body)
 	if err != nil {
+		p.logger.Error("Failed to create forward request", "error", err)
 		http.Error(w, fmt.Sprintf("Failed to create request: %v", err), http.StatusInternalServerError)
 		return
 	}
@@ -213,14 +218,19 @@ func (p *Server) forwardHTTPRequest(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	p.logger.Debug("About to make HTTP request", "target", targetURL.String())
+
 	// Make the request
 	resp, err := client.Do(req)
 	if err != nil {
+		p.logger.Error("Failed to make forward request", "error", err)
 		http.Error(w, fmt.Sprintf("Failed to make request: %v", err), http.StatusBadGateway)
 		return
 	}
 	defer resp.Body.Close()
 
+	p.logger.Debug("Received response", "status", resp.StatusCode, "target", targetURL.String())
+
 	// Copy response headers
 	for name, values := range resp.Header {
 		for _, value := range values {
@@ -232,7 +242,12 @@ func (p *Server) forwardHTTPRequest(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(resp.StatusCode)
 
 	// Copy response body
-	io.Copy(w, resp.Body)
+	_, copyErr := io.Copy(w, resp.Body)
+	if copyErr != nil {
+		p.logger.Debug("Error copying response body", "error", copyErr)
+	} else {
+		p.logger.Debug("Successfully forwarded HTTP response")
+	}
 }
 
 // forwardHTTPSRequest forwards an HTTPS request