main.go

package main

import (
	"bytes"
	"compress/gzip"
	"fmt"
	"io"
	"net/http"
	"os"
	"time"
)

// general error type that
// will hold the custom message
// plus business error logic
type genErr struct {
	message string
	err     error
}

// make genError implement the error interface:w
func (g genErr) Error() string {
	return fmt.Sprintf("%s with the following error %s", g.message, g.err.Error())
}

// create a new cunstom request setting
// headers and body
func newCustomRequest(method, url string) (*http.Request, error) {
	req, err := http.NewRequest(method, url, new(bytes.Buffer))

	if err != nil {
		return nil, &genErr{
			message: fmt.Sprintf("Can't create this custom request with method %s, and url %s", method, url),
			err:     err,
		}
	}

	req.Header.Add("User-Agent", "LinkTracker1.0.0")
	req.Header.Add("Cache-Control", "no-cache")
	req.Header.Add("Connection", "close")
	req.Header.Add("Accept", "text/html")
	req.Header.Add("Accept-Charset", "utf8")
	req.Header.Add("Accept-Encoding", "gzip")
	return req, nil
}

// create a new custom client with a specific timeout duration
// on every request
func newCustomClient(time time.Duration) *http.Client {
	return &http.Client{
		Timeout: time,
	}
}

func main() {
	req, err := newCustomRequest("GET", "http://www.kama.net")
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	// make new http Client object
	// setting the timeout duration for every request
	cli := newCustomClient(5 * time.Second)

	// make the request
	resp, err := cli.Do(req)
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
	defer resp.Body.Close()

	switch resp.StatusCode {
	case 200:
		reader, err := gzip.NewReader(resp.Body)
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		defer reader.Close()

		n, err := io.Copy(os.Stdout, reader)
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}

		fmt.Println("")
		fmt.Println(n)

	default:
		fmt.Fprintf(os.Stderr, "Error occured with status %d ", resp.StatusCode)
		os.Exit(1)
	}
}