basic cli setup

Author: royalbhati

main.go

@@ -0,0 +1,206 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"path"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/muesli/termenv"
+	"github.com/pkg/errors"
+	"github.com/royalbhati/go-tdm/metadata"
+	"github.com/royalbhati/go-tdm/progress"
+)
+
+type Download struct {
+	URL           string
+	TargetPath    string
+	TotalSections int
+	DirPath       string
+}
+
+func main() {
+	p := termenv.ColorProfile()
+
+	startTime := time.Now()
+	var bar progress.Bar
+	bar.NewOption(0, 10)
+
+	var url string
+	fmt.Printf("%s\n", termenv.String(" 🖊️ Paste the url here").Bold().Foreground(p.Color("#FDD835")))
+	fmt.Scanf("%s\n", &url)
+
+	if url == "" {
+		log.Fatal("URL can't be empty")
+	}
+
+	path, err := os.Getwd()
+	if err != nil {
+		log.Println(err)
+	}
+
+	d := Download{
+		URL:           url,
+		TargetPath:    "",
+		TotalSections: 10,
+		DirPath:       path,
+	}
+
+	if err := d.Do(p, &bar); err != nil {
+		fmt.Printf("\n%s\n", termenv.String("An error occured while downloading the file").Foreground(p.Color("0")).Background(p.Color("#E88388")))
+		// fmt.Printf("\n%s", err)
+		log.Fatal(err)
+	}
+
+	fmt.Printf("\n\n ✅ Download completed in %v seconds\n", time.Now().Sub(startTime).Seconds())
+}
+
+func (d Download) Do(p termenv.Profile, bar *progress.Bar) error {
+
+	fmt.Printf("\n%s\n", termenv.String(" 🔍 CHECKING URL ").Bold().Foreground(p.Color("#FDD835")))
+
+	r, err := d.getNewRequest("HEAD")
+	if err != nil {
+		return err
+	}
+
+	resp, err := http.DefaultClient.Do(r)
+
+	if err != nil {
+		return err
+	}
+
+	if resp.StatusCode > 299 {
+		return errors.New(fmt.Sprintf("Can't process, response is %v", resp.StatusCode))
+	}
+
+	fmt.Printf("\n%s\n", termenv.String(" 👍 URL OK ").Bold().Foreground(p.Color("#8BC34A")))
+	size, err := strconv.Atoi(resp.Header.Get("Content-Length"))
+
+	a := metadata.GetFileName(resp)
+	d.TargetPath = a
+
+	if err != nil {
+		return err
+	}
+	var yesOrNo string
+	fmt.Printf("\n%s %f %s\n", termenv.String(" 🗂  SIZE IS ").Bold().Foreground(p.Color("#FFB300")), (float64(size)*float64(0.001))/1000, "MB")
+	fmt.Printf("\n%s\n", termenv.String(" 🚀 PROCEED DOWNLOADING (y/n)").Bold().Foreground(p.Color("#FFB300")))
+	fmt.Scanf("%s", &yesOrNo)
+
+	if yesOrNo == "n" {
+		fmt.Printf("%s\n", termenv.String("EXITING").Bold().Foreground(p.Color("#FF7043")))
+		os.Exit(2)
+		return nil
+	}
+
+	var sections = make([][2]int, d.TotalSections)
+
+	eachSize := size / d.TotalSections
+
+	for i := range sections {
+		if i == 0 {
+			sections[i][0] = 0
+		} else {
+			sections[i][0] = sections[i-1][1] + 1
+		}
+
+		if i < d.TotalSections-1 {
+			sections[i][1] = sections[i][0] + eachSize
+		} else {
+			sections[i][1] = size - 1
+		}
+	}
+
+	var wg sync.WaitGroup
+	sum2 := 0
+
+	for i, s := range sections {
+		wg.Add(1)
+
+		go func(i int, s [2]int, bar *progress.Bar) {
+			defer wg.Done()
+			err = d.downloadSection(i, s, &sum2, p, bar)
+			if err != nil {
+				panic(err)
+			}
+		}(i, s, bar)
+
+	}
+	wg.Wait()
+	return d.mergeFiles(sections)
+}
+func (d Download) downloadSection(i int, c [2]int, sum *int, p termenv.Profile, bar *progress.Bar) error {
+	r, err := d.getNewRequest("GET")
+	if err != nil {
+		return err
+	}
+	r.Header.Set("Range", fmt.Sprintf("bytes=%v-%v", c[0], c[1]))
+	resp, err := http.DefaultClient.Do(r)
+	if err != nil {
+		return err
+	}
+	if resp.StatusCode > 299 {
+		return errors.New(fmt.Sprintf("Can't process, response is %v", resp.StatusCode))
+	}
+
+	b, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return err
+	}
+	err = ioutil.WriteFile(path.Join(d.DirPath, fmt.Sprintf("section-%v.tmp", i)), b, os.ModePerm)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("section-%v.tmp", i)
+	*sum = *sum + 1
+	bar.Play(int64(*sum))
+
+	return nil
+}
+
+// Get a new http request
+func (d Download) getNewRequest(method string) (*http.Request, error) {
+	r, err := http.NewRequest(
+		method,
+		d.URL,
+		nil,
+	)
+	if err != nil {
+		return nil, err
+	}
+	r.Header.Set("User-Agent", "TDM")
+	return r, nil
+}
+
+func (d Download) mergeFiles(sections [][2]int) error {
+	f, err := os.OpenFile(path.Join(d.DirPath, d.TargetPath), os.O_CREATE|os.O_WRONLY|os.O_APPEND, os.ModePerm)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	for i := range sections {
+		tmpFileName := fmt.Sprintf("section-%v.tmp", i)
+		b, err := ioutil.ReadFile(path.Join(d.DirPath, tmpFileName))
+		if err != nil {
+			return err
+		}
+		_, err = f.Write(b)
+		if err != nil {
+			return err
+		}
+		err = os.Remove(tmpFileName)
+		if err != nil {
+			return err
+		}
+
+	}
+
+	return nil
+
+}