Spring Boot (Java)

Para aplicaciones corporativas Java, la manera más robusta de integrar ProxyTracer es creando un HandlerInterceptor global. Esto garantiza que cada solicitud HTTP entrante se verifique antes de llegar a tus controladores.

El Interceptor

Esta implementación extrae con seguridad la IP desde el balanceador de carga (gestionando X-Forwarded-For), llama a ProxyTracer usando el HttpClient nativo de Java y bloquea la solicitud si detecta riesgo.


import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;
 
@Component
public class ProxyTracerInterceptor implements HandlerInterceptor {
 
    private static final String API_KEY = System.getenv("PROXYTRACER_API_KEY");
    private final HttpClient httpClient = HttpClient.newBuilder()
            .connectTimeout(Duration.ofMillis(500)) // Strict timeout to prevent bottlenecking
            .build();
 
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        
        // 1. Safely extract the real IP behind load balancers/NGINX
        String ipAddress = request.getHeader("X-Forwarded-For");
        if (ipAddress == null || ipAddress.isEmpty()) {
            ipAddress = request.getRemoteAddr();
        } else {
            ipAddress = ipAddress.split(",")[0].trim();
        }
 
        // 2. Query ProxyTracer API
        HttpRequest ptRequest = HttpRequest.newBuilder()
                .uri(URI.create("https://api.proxytracer.com/v1/check/" + ipAddress))
                .header("Authorization", "Bearer " + API_KEY)
                .GET()
                .build();
 
        try {
            HttpResponse<String> ptResponse = httpClient.send(ptRequest, HttpResponse.BodyHandlers.ofString());
 
            if (ptResponse.statusCode() == 200) {
                // 3. Simple string matching (Avoids heavy JSON parsing libraries for raw speed)
                if (ptResponse.body().contains("\"proxy\": true") || ptResponse.body().contains("\"proxy\":true")) {
                    response.setStatus(HttpServletResponse.SC_FORBIDDEN);
                    response.getWriter().write("{\"error\": \"Access Denied: VPN or Proxy detected.\"}");
                    response.setContentType("application/json");
                    return false; // Drops the request
                }
            }
        } catch (Exception e) {
            // Fail open: log the error and allow the request through
            System.err.println("ProxyTracer validation failed: " + e.getMessage());
        }
 
        // 4. Traffic is clean, proceed to the controller
        return true; 
    }
}

Configuration:

No olvides registrar este interceptor en tu clase WebMvcConfigurer para aplicarlo de forma global a todas las rutas de tu aplicación.