A go program to configure TLS for server certificate

prog_05.go

package main

import (
	"crypto/tls"
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"net/http"
	"os"
	"time"
)

func getCertPool(fileName string) *x509.CertPool {
	// Load the server certificate from a file
	certBytes, err := os.ReadFile(fileName)
	if err != nil {
		fmt.Println("Error reading certificate file:", err)
		return nil
	}

	// Decode the PEM-encoded certificate
	pemBlock, _ := pem.Decode(certBytes)
	if pemBlock == nil {
		fmt.Println("Failed to decode PEM block")
		return nil
	}

	// Parse the certificate data
	cert, err := x509.ParseCertificate(pemBlock.Bytes)
	if err != nil {
		fmt.Println("Error parsing certificate:", err)
		return nil
	}

	// Create a certificate pool and add the server certificate to it
	pool := x509.NewCertPool()
	pool.AddCert(cert)

	return pool
}

func main() {
	// Create a custom transport with a certificate pool
	transport := &http.Transport{
		MaxIdleConns:        1,
		MaxIdleConnsPerHost: 1,
		IdleConnTimeout:     30 * time.Second,
		TLSClientConfig:     &tls.Config{RootCAs: getCertPool("httpbin.cer")},
	}

	// Create a client with the custom transport
	client := &http.Client{Transport: transport, Timeout: 5 * time.Second}
	defer client.CloseIdleConnections()

	req, err := http.NewRequest("GET", "https://httpbin.org/get", nil)
	if err != nil {
		fmt.Println(err)
		return
	}
	
	// Add headers to the request
	req.Header.Add("User-Agent", "go-http-client")
	req.Header.Add("Content-Type", "application/json")

	// Send the request
	resp, err := client.Do(req)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println(resp.StatusCode)
}