Spring Boot (Java)

对于企业级 Java 应用，最稳健的集成方式是实现全局 HandlerInterceptor。这可确保所有传入的 HTTP 请求在抵达 Controller 控制器之前均完成安全核验。

拦截器实现

此实现安全提取反向代理之后的真实 IP（解析 X-Forwarded-For），使用 Java 原生 HttpClient 调用 ProxyTracer，并在标记为代理时直接阻断请求。


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)) // 严格的超时限制以避免产生性能瓶颈
            .build();
 
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        
        // 1. 安全提取负载均衡器/NGINX 背后的真实 IP
        String ipAddress = request.getHeader("X-Forwarded-For");
        if (ipAddress == null || ipAddress.isEmpty()) {
            ipAddress = request.getRemoteAddr();
        } else {
            ipAddress = ipAddress.split(",")[0].trim();
        }
 
        // 2. 查询 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. 简单字符串匹配（避免引入重量级 JSON 解析库以追求极致性能）
                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; // 丢弃该请求
                }
            }
        } catch (Exception e) {
            // 故障开放（Fail-open）：记录错误并放行请求
            System.err.println("ProxyTracer validation failed: " + e.getMessage());
        }
 
        // 4. 流量正常，继续放行至控制器
        return true; 
    }
}

配置说明：

请务必在 WebMvcConfigurer 配置类中注册该拦截器，以便将其全局应用于应用路由。