Uso de Proxies con cURL

cURL es una potente utilidad de línea de comandos para HTTP. Soporta excelentemente todos los tipos de proxy.

Sintaxis Básica

curl -x [protocol://]host:port URL

Proxy HTTP

# Solicitud simple a través de proxy
curl -x http://proxy.example.com:8080 https://httpbin.org/ip

# Con autenticación
curl -x http://user:password@proxy.example.com:8080 https://httpbin.org/ip

# O por separado
curl -x http://proxy.example.com:8080 -U user:password https://httpbin.org/ip

Proxy HTTPS

curl -x https://proxy.example.com:8080 https://httpbin.org/ip

Proxy SOCKS

# SOCKS4
curl --socks4 proxy.example.com:1080 https://httpbin.org/ip

# SOCKS4A (DNS a través de proxy)
curl --socks4a proxy.example.com:1080 https://httpbin.org/ip

# SOCKS5
curl --socks5 proxy.example.com:1080 https://httpbin.org/ip

# SOCKS5 con DNS a través de proxy (recomendado)
curl --socks5-hostname proxy.example.com:1080 https://httpbin.org/ip

Variables de Entorno

# Establecer proxy globalmente
export http_proxy=http://proxy.example.com:8080
export https_proxy=http://proxy.example.com:8080

# Ahora todas las solicitudes pasan por el proxy
curl https://httpbin.org/ip

# Ignorar proxy para ciertos hosts
export no_proxy=localhost,127.0.0.1,.internal.com

Opciones Útiles

# Mostrar tiempo de conexión
curl -x http://proxy:8080 -w "Time: %{time_total}s\n" https://httpbin.org/ip

# Ignorar errores SSL
curl -x http://proxy:8080 -k https://example.com

# Establecer tiempo de espera
curl -x http://proxy:8080 --connect-timeout 10 https://httpbin.org/ip

# Seguir redirecciones
curl -x http://proxy:8080 -L https://httpbin.org/redirect/3

# Guardar cookies
curl -x http://proxy:8080 -c cookies.txt https://example.com

# Enviar solicitud POST
curl -x http://proxy:8080 -X POST -d "data=value" https://httpbin.org/post

Script de Verificación de Lista de Proxies

#!/bin/bash
while read proxy; do
    result=$(curl -x "$proxy" -s --connect-timeout 5 https://httpbin.org/ip)
    if [ $? -eq 0 ]; then
        echo "[OK] $proxy"
    else
        echo "[FAIL] $proxy"
    fi
done < proxies.txt

Depuración

# Salida detallada
curl -x http://proxy:8080 -v https://httpbin.org/ip

# Mostrar solo cabeceras
curl -x http://proxy:8080 -I https://httpbin.org/ip