NordVPN Proxy and HTTP Request

proxy_request.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"time"

	"golang.org/x/net/proxy"
)

const (
	NordServerListEndpoint = "https://nordvpn.com/api/server"
	NordSocks5Port         = "1080"
)

var (
	NordUser         = os.Getenv("NORD_EMAIL")
	NordPassword     = os.Getenv("NORD_PASSWORD")
	NordProxyServers = []NordServer{}
)

type NordServer struct {
	IPAddress string `json:"ip_address"`
	Domain    string `json:"domain"`
	Country   string `json:"country"`
	Features  struct {
		Socks bool `json:"socks"`
	} `json:"features"`
}

const TestURL = "https://ifconfig.me"

var (
	ProxyRound         int
	httpTransportCache = map[string]*http.Transport{}
)

func main() {
	var err error
	NordProxyServers, err = GetServerList()
	if err != nil {
		log.Fatal(err)
	}

	for i := 0; i < 50; i++ {
		proxyServer := NordProxyServers[ProxyRound%len(NordProxyServers)]
		ProxyRound++

		// setup a http client
		cachedHttpTransport, exist := httpTransportCache[proxyServer.Domain]
		if !exist {
			// create a socks5 dialer
			dialer, err := proxy.SOCKS5("tcp", proxyServer.Domain+":"+NordSocks5Port, &proxy.Auth{
				User:     NordUser,
				Password: NordPassword,
			}, proxy.Direct)
			if err != nil {
				fmt.Fprintln(os.Stderr, "can't connect to the proxy:", err)
				continue
			}

			cachedHttpTransport = &http.Transport{}
			if contextDialer, ok := dialer.(proxy.ContextDialer); ok {
				cachedHttpTransport.DialContext = contextDialer.DialContext
			}
			httpTransportCache[proxyServer.Domain] = cachedHttpTransport
		}

		IP, err := GetMyIP(cachedHttpTransport.Clone())
		if err != nil {
			fmt.Fprintln(os.Stderr, "can't get the IP address:", err)
			continue
		}

		fmt.Printf("IP:%s ProxyDomain:%s ProxyCountry:%s\n", string(IP), proxyServer.Domain, proxyServer.Domain)
	}
}

func GetMyIP(httpTransport *http.Transport) ([]byte, error) {
	defer httpTransport.CloseIdleConnections()

	httpClient := &http.Client{
		Transport: httpTransport,
		Timeout:   15 * time.Second,
	}

	// Do request
	resp, err := httpClient.Get(TestURL)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	return ioutil.ReadAll(resp.Body)
}

func GetServerList() ([]NordServer, error) {
	resp, err := http.Get(NordServerListEndpoint)
	if err != nil {
		return nil, err
	}

	if resp.StatusCode != 200 {
		return nil, fmt.Errorf("Response status code is %d", resp.StatusCode)
	}

	respByte, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	result := []NordServer{}
	err = json.Unmarshal(respByte, &result)
	if err != nil {
		return nil, err
	}

	output := []NordServer{}
	for _, s := range result {
		if s.Features.Socks {
			output = append(output, s)
		}
	}

	return output, nil
}