Skyeng lessons downloader

skyeng.go

package main

import (
	"bufio"
	"fmt"
	"io"
	"net/http"
	"os"
	"regexp"
	"strings"
	"sync"
)

// change this to your dir
const lessonsDir = "/Users/home/Documents/skyeng_lessons"

var semaphore = make(chan struct{}, 10)

func main() {
  // same
	fd, err := os.Open("/Users/home/Desktop/ws/tools/tmp/lessons.txt")
	if err != nil {
		panic(err)
	}

	sc := bufio.NewScanner(fd)
	var wg sync.WaitGroup
	for sc.Scan() {
		wg.Add(1)

		url := sc.Text()
		go func() {
			defer wg.Done()

			semaphore <- struct{}{}
			downloadFile(url)
			<-semaphore
		}()
	}

	wg.Wait()
	fmt.Println("Finished")

	if err := sc.Err(); err != nil {
		panic(err)
	}
}

var re = regexp.MustCompile("\\d{4}/\\d{2}/\\d{2}")

func downloadFile(url string) {
	defer func() {
		if r := recover(); r != nil {
			panic(fmt.Errorf("%v (url=%s)", r, url))
		}
	}()

	fmt.Println("Downloading", url)

	dateStr := re.FindStringSubmatch(url)[0]
	dateStr = strings.ReplaceAll(dateStr, "/", "-")

	filename := fmt.Sprintf("skyeng-%s.mp3", dateStr)
	path := lessonsDir + "/" + filename
	fd, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE, 0666)
	if err != nil {
		panic(err)
	}

	resp, err := http.Get(url)
	if err != nil {
		panic(err)
	}
	defer resp.Body.Close()

	_, err = io.Copy(fd, resp.Body)
	if err != nil {
		panic(err)
	}
}

This script expects txt file where each line corresponds to some URL