proxy-fiddle.go

package main

import (
	"fmt"
	"net/http"
	"net/url"
	"sync"
)

type ProxyConfig struct {
	mu    sync.Mutex
	proxy *url.URL
}

func (ps *ProxyConfig) Set(proxyStr string) error {
	ps.mu.Lock()
	defer ps.mu.Unlock()
	proxyURL, err := url.Parse(proxyStr)
	if err != nil {
		return err
	}
	ps.proxy = proxyURL
	return nil
}

func (ps *ProxyConfig) GetProxy(req *http.Request) (*url.URL, error) {
	ps.mu.Lock()
	defer ps.mu.Unlock()
	return ps.proxy, nil
}

func main() {
	config := new(ProxyConfig)
	//config.Set("http://1.2.3.4:8000/")
	config.Set("http://127.0.0.1:8888/")
	transport := http.DefaultTransport.(*http.Transport)
	transport.Proxy = config.GetProxy

	client := new(http.Client)
	_, err := client.Get("http://google.com/")
	fmt.Println(err)
}