Go: How to use a proxy server with `net/http` (ft. Bright Data)

proxy_client.go

// Please refer to the following code if you encounter "tls: failed to verify certificate: x509: “*.example.com” certificate is not standards compliant"
package main

import (
	"crypto/tls"
	"crypto/x509"
	"errors"
	"net"
	"net/http"
	"net/url"
)

//go:embed proxy.crt
var proxyCert []byte

// NewProxyClient creates an HTTP client configured to use a proxy server
// with a custom CA certificate. This helps resolve "tls: failed to verify certificate:
// x509: “*.example.com” certificate is not standards compliant" errors.
func NewProxyClient() (*http.Client, error) {
	const (
		proxyUser     = "user"
		proxyPassword = "password"
		proxyHost     = "proxy.example.com"
		proxyPort     = "33335"
	)
	proxyURL := &url.URL{
		Scheme: "http",
		User:   url.UserPassword(proxyUser, proxyPassword),
		Host:   net.JoinHostPort(proxyHost, proxyPort),
	}
	// Download and use the proxy server's CA certificate to avoid the
	// `tls: failed to verify certificate: x509: “*.example.com” certificate is not standards compliant` error.
	// Check out https://docs.brightdata.com/general/account/ssl-certificate.
	pool := x509.NewCertPool()
	ok := pool.AppendCertsFromPEM(proxyCert)
	if !ok {
		return nil, errors.New("AppendCertsFromPEM failed")
	}
	return &http.Client{
		Transport: &http.Transport{
			Proxy:           http.ProxyURL(proxyURL),
			TLSClientConfig: &tls.Config{RootCAs: pool},
			DisableKeepAlives: true,
		},
	}, nil
}