Added new download options

downloader.go

@@ -0,0 +1,186 @@
+package crunchyroll
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"fmt"
+	"github.com/grafov/m3u8"
+	"io/ioutil"
+	"math"
+	"net/http"
+	"os"
+	"path/filepath"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+type Downloader struct {
+	// Filename is the filename of the output file
+	Filename string
+	// TempDir is the directory where the temporary files should be stored
+	TempDir string
+	// If IgnoreExisting is true, existing Filename's and TempDir's may be
+	// overwritten or deleted
+	IgnoreExisting bool
+	// If DeleteTempAfter is true, the temp directory gets deleted afterwards
+	DeleteTempAfter bool
+
+	// Goroutines is the number of goroutines to download segments with
+	Goroutines int
+
+	// A method to call when a segment was downloaded
+	OnSegmentDownload func(segment *m3u8.MediaSegment, current, total int, file *os.File) error
+
+	// If FFmpeg is true, ffmpeg will used to merge and convert files
+	FFmpeg bool
+}
+
+func NewDownloader(filename string, goroutines int, onSegmentDownload func(segment *m3u8.MediaSegment, current, total int, file *os.File) error) Downloader {
+	tmp, _ := os.MkdirTemp("", "crunchy_")
+
+	return Downloader{
+		Filename:          filename,
+		TempDir:           tmp,
+		DeleteTempAfter:   true,
+		Goroutines:        goroutines,
+		OnSegmentDownload: onSegmentDownload,
+	}
+}
+
+// download downloads every mpeg transport stream segment to a given directory (more information below).
+// After every segment download onSegmentDownload will be called with:
+//		the downloaded segment, the current position, the total size of segments to download, the file where the segment content was written to an error (if occurred).
+// The filename is always <number of downloaded segment>.ts
+//
+// Short explanation:
+// 		The actual crunchyroll video is split up in multiple segments (or video files) which have to be downloaded and merged after to generate a single video file.
+//		And this function just downloads each of this segment into the given directory.
+// 		See https://en.wikipedia.org/wiki/MPEG_transport_stream for more information
+func download(format *Format, tempDir string, goroutines int, onSegmentDownload func(segment *m3u8.MediaSegment, current, total int, file *os.File) error) error {
+	resp, err := format.crunchy.Client.Get(format.Video.URI)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	// reads the m3u8 file
+	playlist, _, err := m3u8.DecodeFrom(resp.Body, true)
+	if err != nil {
+		return err
+	}
+	// extracts the segments from the playlist
+	var segments []*m3u8.MediaSegment
+	for _, segment := range playlist.(*m3u8.MediaPlaylist).Segments {
+		// some segments are nil, so they have to be filtered out
+		if segment != nil {
+			segments = append(segments, segment)
+		}
+	}
+
+	var wg sync.WaitGroup
+	chunkSize := int(math.Ceil(float64(len(segments)) / float64(goroutines)))
+
+	// when a onSegmentDownload call returns an error, this channel will be set to true and stop all goroutines
+	quit := make(chan bool)
+
+	// receives the decrypt block and iv from the first segment.
+	// in my tests, only the first segment has specified this data, so the decryption data from this first segments will be used in every other segment too
+	block, iv, err := getCrypt(format, segments[0])
+	if err != nil {
+		return err
+	}
+
+	var total int32
+	for i := 0; i < len(segments); i += chunkSize {
+		wg.Add(1)
+		end := i + chunkSize
+		if end > len(segments) {
+			end = len(segments)
+		}
+		i := i
+
+		go func() {
+			for j, segment := range segments[i:end] {
+				select {
+				case <-quit:
+					break
+				default:
+					var file *os.File
+					k := 1
+					for ; k < 4; k++ {
+						file, err = downloadSegment(format, segment, filepath.Join(tempDir, fmt.Sprintf("%d.ts", i+j)), block, iv)
+						if err == nil {
+							break
+						}
+						// sleep if an error occurs. very useful because sometimes the connection times out
+						time.Sleep(5 * time.Duration(k) * time.Second)
+					}
+					if k == 4 {
+						quit <- true
+						return
+					}
+					if onSegmentDownload != nil {
+						if err = onSegmentDownload(segment, int(atomic.AddInt32(&total, 1)), len(segments), file); err != nil {
+							quit <- true
+							file.Close()
+							return
+						}
+					}
+					file.Close()
+				}
+			}
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+
+	select {
+	case <-quit:
+		return err
+	default:
+		return nil
+	}
+}
+
+// getCrypt extracts the key and iv of a m3u8 segment and converts it into a cipher.Block block and a iv byte sequence
+func getCrypt(format *Format, segment *m3u8.MediaSegment) (block cipher.Block, iv []byte, err error) {
+	var resp *http.Response
+
+	resp, err = format.crunchy.Client.Get(segment.Key.URI)
+	if err != nil {
+		return nil, nil, err
+	}
+	defer resp.Body.Close()
+	key, err := ioutil.ReadAll(resp.Body)
+
+	block, err = aes.NewCipher(key)
+	if err != nil {
+		return nil, nil, err
+	}
+	iv = []byte(segment.Key.IV)
+	if len(iv) == 0 {
+		iv = key
+	}
+
+	return block, iv, nil
+}
+
+// downloadSegment downloads a segment, decrypts it and names it after the given index
+func downloadSegment(format *Format, segment *m3u8.MediaSegment, filename string, block cipher.Block, iv []byte) (*os.File, error) {
+	// every segment is aes-128 encrypted and has to be decrypted when downloaded
+	content, err := decryptSegment(format.crunchy.Client, segment, block, iv)
+	if err != nil {
+		return nil, err
+	}
+
+	file, err := os.Create(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+	if _, err = file.Write(content); err != nil {
+		return nil, err
+	}
+
+	return file, nil
+}

format.go

@@ -2,29 +2,24 @@ package crunchyroll
 
 import (
 	"bufio"
-	"crypto/aes"
-	"crypto/cipher"
 	"fmt"
 	"github.com/grafov/m3u8"
 	"io/ioutil"
-	"math"
-	"net/http"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"sort"
 	"strconv"
 	"strings"
-	"sync"
-	"sync/atomic"
-	"time"
 )
 
+type FormatType string
+
 const (
 	EPISODE FormatType = "episodes"
 	MOVIE              = "movies"
 )
 
-type FormatType string
 type Format struct {
 	crunchy *Crunchyroll
 
@@ -37,166 +32,50 @@ type Format struct {
 	Subtitles   []*Subtitle
 }
 
-// DownloadGoroutines downloads the format to the given output file (as .ts file).
+func (f *Format) Download(downloader Downloader) error {
-// See Format.DownloadSegments for more information
+	if _, err := os.Stat(downloader.Filename); err == nil && !downloader.IgnoreExisting {
-func (f *Format) DownloadGoroutines(output *os.File, goroutines int, onSegmentDownload func(segment *m3u8.MediaSegment, current, total int, file *os.File) error) error {
+		return fmt.Errorf("file %s already exists", downloader.Filename)
-	downloadDir, err := os.MkdirTemp("", "crunchy_")
+	}
+	if _, err := os.Stat(downloader.TempDir); err == nil && !downloader.IgnoreExisting {
+		content, err := os.ReadDir(downloader.TempDir)
 		if err != nil {
 			return err
 		}
-	defer os.RemoveAll(downloadDir)
+		if len(content) > 0 {
-
+			return fmt.Errorf("directory %s is not empty", downloader.Filename)
-	if err := f.DownloadSegments(downloadDir, goroutines, onSegmentDownload); err != nil {
+		}
+	} else if err != nil && os.IsNotExist(err) {
+		if err := os.Mkdir(downloader.TempDir, 0755); err != nil {
+			return err
+		}
+	} else {
 		return err
 	}
 
-	return f.mergeSegments(downloadDir, output)
+	if err := download(f, downloader.TempDir, downloader.Goroutines, downloader.OnSegmentDownload); err != nil {
-}
-
-// DownloadSegments downloads every mpeg transport stream segment to a given directory (more information below).
-// After every segment download onSegmentDownload will be called with:
-//		the downloaded segment, the current position, the total size of segments to download, the file where the segment content was written to an error (if occurred).
-// The filename is always <number of downloaded segment>.ts
-//
-// Short explanation:
-// 		The actual crunchyroll video is split up in multiple segments (or video files) which have to be downloaded and merged after to generate a single video file.
-//		And this function just downloads each of this segment into the given directory.
-// 		See https://en.wikipedia.org/wiki/MPEG_transport_stream for more information
-func (f *Format) DownloadSegments(outputDir string, goroutines int, onSegmentDownload func(segment *m3u8.MediaSegment, current, total int, file *os.File) error) error {
-	resp, err := f.crunchy.Client.Get(f.Video.URI)
-	if err != nil {
-		return err
-	}
-	defer resp.Body.Close()
-	// reads the m3u8 file
-	playlist, _, err := m3u8.DecodeFrom(resp.Body, true)
-	if err != nil {
-		return err
-	}
-	// extracts the segments from the playlist
-	var segments []*m3u8.MediaSegment
-	for _, segment := range playlist.(*m3u8.MediaPlaylist).Segments {
-		// some segments are nil, so they have to be filtered out
-		if segment != nil {
-			segments = append(segments, segment)
-		}
-	}
-
-	var wg sync.WaitGroup
-	chunkSize := int(math.Ceil(float64(len(segments)) / float64(goroutines)))
-
-	// when a onSegmentDownload call returns an error, this channel will be set to true and stop all goroutines
-	quit := make(chan bool)
-
-	// receives the decrypt block and iv from the first segment.
-	// in my tests, only the first segment has specified this data, so the decryption data from this first segments will be used in every other segment too
-	block, iv, err := f.getCrypt(segments[0])
-	if err != nil {
 		return err
 	}
 
-	var total int32
+	if downloader.FFmpeg {
-	for i := 0; i < len(segments); i += chunkSize {
+		return mergeSegmentsFFmpeg(downloader.TempDir, downloader.Filename)
-		wg.Add(1)
+	} else {
-		end := i + chunkSize
+		return mergeSegments(downloader.TempDir, downloader.Filename)
-		if end > len(segments) {
-			end = len(segments)
-		}
-		i := i
-
-		go func() {
-			for j, segment := range segments[i:end] {
-				select {
-				case <-quit:
-					break
-				default:
-					var file *os.File
-					k := 1
-					for ; k < 4; k++ {
-						file, err = f.downloadSegment(segment, filepath.Join(outputDir, fmt.Sprintf("%d.ts", i+j)), block, iv)
-						if err == nil {
-							break
-						}
-						// sleep if an error occurs. very useful because sometimes the connection times out
-						time.Sleep(5 * time.Duration(k) * time.Second)
-					}
-					if k == 4 {
-						quit <- true
-						return
-					}
-					if onSegmentDownload != nil {
-						if err = onSegmentDownload(segment, int(atomic.AddInt32(&total, 1)), len(segments), file); err != nil {
-							quit <- true
-							file.Close()
-							return
-						}
-					}
-					file.Close()
-				}
-			}
-			wg.Done()
-		}()
-	}
-	wg.Wait()
-
-	select {
-	case <-quit:
-		return err
-	default:
-		return nil
 	}
 }
 
-// getCrypt extracts the key and iv of a m3u8 segment and converts it into a cipher.Block block and a iv byte sequence
+// mergeSegments reads every file in tempDir and writes their content to the outputFile.
-func (f *Format) getCrypt(segment *m3u8.MediaSegment) (block cipher.Block, iv []byte, err error) {
+// The given output file gets created or overwritten if already existing
-	var resp *http.Response
+func mergeSegments(tempDir string, outputFile string) error {
-
+	dir, err := os.ReadDir(tempDir)
-	resp, err = f.crunchy.Client.Get(segment.Key.URI)
 	if err != nil {
-		return nil, nil, err
+		return err
 	}
-	defer resp.Body.Close()
+	file, err := os.OpenFile(outputFile, os.O_CREATE|os.O_WRONLY, 0755)
-	key, err := ioutil.ReadAll(resp.Body)
-
-	block, err = aes.NewCipher(key)
 	if err != nil {
-		return nil, nil, err
+		return err
-	}
-	iv = []byte(segment.Key.IV)
-	if len(iv) == 0 {
-		iv = key
-	}
-
-	return block, iv, nil
-}
-
-// downloadSegment downloads a segment, decrypts it and names it after the given index
-func (f *Format) downloadSegment(segment *m3u8.MediaSegment, filename string, block cipher.Block, iv []byte) (*os.File, error) {
-	// every segment is aes-128 encrypted and has to be decrypted when downloaded
-	content, err := decryptSegment(f.crunchy.Client, segment, block, iv)
-	if err != nil {
-		return nil, err
-	}
-
-	file, err := os.Create(filename)
-	if err != nil {
-		return nil, err
 	}
 	defer file.Close()
-	if _, err = file.Write(content); err != nil {
+	writer := bufio.NewWriter(file)
-		return nil, err
-	}
-
-	return file, nil
-}
-
-// mergeSegments reads every file in tempPath and writes their content to output
-func (f *Format) mergeSegments(tempPath string, output *os.File) error {
-	dir, err := os.ReadDir(tempPath)
-	if err != nil {
-		return err
-	}
-	writer := bufio.NewWriter(output)
 	defer writer.Flush()
 
 	// sort the directory files after their numeric names
@@ -213,7 +92,7 @@ func (f *Format) mergeSegments(tempPath string, output *os.File) error {
 	})
 
 	for _, file := range dir {
-		bodyAsBytes, err := ioutil.ReadFile(filepath.Join(tempPath, file.Name()))
+		bodyAsBytes, err := ioutil.ReadFile(filepath.Join(tempDir, file.Name()))
 		if err != nil {
 			return err
 		}
@@ -223,3 +102,28 @@ func (f *Format) mergeSegments(tempPath string, output *os.File) error {
 	}
 	return nil
 }
+
+// mergeSegmentsFFmpeg reads every file in tempDir and merges their content to the outputFile
+// with ffmpeg (https://ffmpeg.org/).
+// The given output file gets created or overwritten if already existing
+func mergeSegmentsFFmpeg(tempDir string, outputFile string) error {
+	dir, err := os.ReadDir(tempDir)
+	if err != nil {
+		return err
+	}
+	f, err := os.CreateTemp("", "*.txt")
+	if err != nil {
+		return err
+	}
+	defer os.Remove(f.Name())
+	for i := 0; i < len(dir); i++ {
+		fmt.Fprintf(f, "file '%s.ts'\n", filepath.Join(tempDir, strconv.Itoa(i)))
+	}
+	cmd := exec.Command("ffmpeg",
+		"-f", "concat",
+		"-safe", "0",
+		"-i", f.Name(),
+		"-c", "copy",
+		outputFile)
+	return cmd.Run()
+}