Go net/http default client proxy override

main.go

package main

import (
	"io/ioutil"
	"log"
	"net"
	"net/http"
	"net/url"
	"time"
)

func main() {
	const URL = "https://ip.p1k.se"

	proxyurl, err := url.Parse("socks5://localhost:1337")
	if err != nil {
		log.Fatalf("Error parsing proxy URL: %q", err)
	}

	http.DefaultClient.Transport = &http.Transport{
		Proxy: http.ProxyURL(proxyurl),
		DialContext: (&net.Dialer{
			Timeout:   30 * time.Second,
			KeepAlive: 30 * time.Second,
		}).DialContext,
		ForceAttemptHTTP2:     true,
		MaxIdleConns:          100,
		IdleConnTimeout:       90 * time.Second,
		TLSHandshakeTimeout:   10 * time.Second,
		ExpectContinueTimeout: 1 * time.Second,
	}

	log.Printf("Fetching response from %q", URL)

	resp, err := http.Get(URL)
	if err != nil {
		log.Fatalf("Error fetching from remote: %v", err)
	}

	log.Printf("Got response status %s", resp.Status)

	defer resp.Body.Close()
	buffer, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Fatalf("Error reading response body: %v", err)
	}

	body := string(buffer)

	log.Printf("Body: %q", body)
}