FastAPI (Python)

FastAPI está construido para aplicaciones web asíncronas de alto rendimiento. Para mantener esa velocidad, integramos ProxyTracer utilizando un BaseHTTPMiddleware personalizado y un cliente HTTP asíncrono (httpx) para asegurar que el bucle de eventos nunca se bloquee.

El Middleware

Esta implementación extrae con seguridad la IP real del cliente, utiliza un grupo de conexiones asíncronas para consultar ProxyTracer y devuelve un estricto 403 Forbidden si la variable proxy es verdadera.


import os
import httpx
from fastapi import FastAPI, Request, status
from fastapi.responses import JSONResponse
from starlette.middleware.base import BaseHTTPMiddleware
 
app = FastAPI()
 
class ProxyTracerMiddleware(BaseHTTPMiddleware):
    def __init__(self, app):
        super().__init__(app)
        self.api_key = os.getenv("PROXYTRACER_API_KEY")
        # Initialize a persistent async client for connection pooling and raw speed
        self.client = httpx.AsyncClient(timeout=0.5) # Strict 500ms timeout
 
    async def dispatch(self, request: Request, call_next):
        # 1. Safely extract the real IP behind load balancers/proxies
        forwarded_for = request.headers.get("x-forwarded-for")
        if forwarded_for:
            ip = forwarded_for.split(",")[0].strip()
        else:
            ip = request.client.host if request.client else None
 
        # Skip local development IPs
        if ip and ip not in ["127.0.0.1", "::1", "testclient"]:
            try:
                # 2. Query ProxyTracer API asynchronously
                response = await self.client.get(
                    f"https://api.proxytracer.com/v1/check/{ip}",
                    headers={"Authorization": f"Bearer {self.api_key}"}
                )
                
                if response.status_code == 200:
                    data = response.json()
                    
                    # 3. Drop the connection immediately if a proxy is detected
                    if data.get("proxy") is True:
                        return JSONResponse(
                            status_code=status.HTTP_403_FORBIDDEN,
                            content={"error": "Access Denied: VPN or Proxy detected."}
                        )
            except httpx.RequestError as e:
                # Fail open: Log the network error and allow the request to proceed
                print(f"ProxyTracer API timeout or failure: {e}")
 
        # 4. Traffic is clean, proceed to the route handler
        return await call_next(request)
 
# Apply the middleware globally
app.add_middleware(ProxyTracerMiddleware)

Nota de Dependencia: Esta implementación requiere la biblioteca httpx para realizar solicitudes HTTP asíncronas. Instálala ejecutando pip install httpx.