Merge pull request #155 from Galiley/master

add options to handle downloading one entry from a playlist

goutubedl.go

@@ -270,8 +270,8 @@ func infoFromURL(ctx context.Context, rawURL string, options Options) (info Info
 	if options.Downloader != "" {
 		cmd.Args = append(cmd.Args, "--downloader", options.Downloader)
 	}
-
-	if options.Type == TypePlaylist {
+	switch options.Type {
+	case TypePlaylist:
 		cmd.Args = append(cmd.Args, "--yes-playlist")
 
 		if options.PlaylistStart > 0 {
@@ -284,7 +284,7 @@ func infoFromURL(ctx context.Context, rawURL string, options Options) (info Info
 				"--playlist-end", strconv.Itoa(int(options.PlaylistEnd)),
 			)
 		}
-	} else {
+	case TypeSingle:
 		if options.DownloadSubtitles {
 			cmd.Args = append(cmd.Args,
 				"--all-subs",
@@ -293,6 +293,10 @@ func infoFromURL(ctx context.Context, rawURL string, options Options) (info Info
 		cmd.Args = append(cmd.Args,
 			"--no-playlist",
 		)
+	case TypeAny:
+		break
+	default:
+		return Info{}, nil, fmt.Errorf("Unhandle options type value: %d", options.Type)
 	}
 
 	tempPath, _ := ioutil.TempDir("", "ydls")
@@ -429,11 +433,27 @@ type DownloadResult struct {
 
 // Download format matched by filter (usually a format id or quality designator).
 // If filter is empty, then youtube-dl will use its default format selector.
+// It's a shortcut of DownloadWithOptions where the options use the default value
 func (result Result) Download(ctx context.Context, filter string) (*DownloadResult, error) {
+	return result.DownloadWithOptions(ctx, DownloadOptions{
+		Filter: filter,
+	})
+}
+
+type DownloadOptions struct {
+	// Download format matched by filter (usually a format id or quality designator).
+	// If filter is empty, then youtube-dl will use its default format selector.
+	Filter string
+	// The index of the entry to download from the playlist that would be
+	// passed to youtube-dl via --playlist-items. The index value starts at 1
+	PlaylistIndex int
+}
+
+func (result Result) DownloadWithOptions(ctx context.Context, options DownloadOptions) (*DownloadResult, error) {
 	debugLog := result.Options.DebugLog
 
-	if result.Info.Type == "playlist" || result.Info.Type == "multi_video" {
-		return nil, fmt.Errorf("can't download a playlist")
+	if (result.Info.Type == "playlist" || result.Info.Type == "multi_video") && options.PlaylistIndex == 0 {
+		return nil, fmt.Errorf("can't download a playlist when the playlist index options is not set")
 	}
 
 	tempPath, tempErr := ioutil.TempDir("", "ydls")
@@ -463,8 +483,12 @@ func (result Result) Download(ctx context.Context, filter string) (*DownloadResu
 	)
 	// don't need to specify if direct as there is only one
 	// also seems to be issues when using filter with generic extractor
-	if !result.Info.Direct && filter != "" {
-		cmd.Args = append(cmd.Args, "-f", filter)
+	if !result.Info.Direct && options.Filter != "" {
+		cmd.Args = append(cmd.Args, "-f", options.Filter)
+	}
+
+	if options.PlaylistIndex > 0 {
+		cmd.Args = append(cmd.Args, "--playlist-items", fmt.Sprint(options.PlaylistIndex))
 	}
 
 	if result.Options.ProxyUrl != "" {

goutubedl_test.go

@@ -301,3 +301,122 @@ func TestOptionDownloader(t *testing.T) {
 	}
 	dr.Close()
 }
+
+func TestInvalidOptionTypeField(t *testing.T) {
+	defer leakChecks(t)()
+
+	_, err := goutubedl.New(context.Background(), playlistRawURL, goutubedl.Options{
+		Type: 42,
+	})
+	if err == nil {
+		t.Error("should have failed")
+	}
+}
+
+func TestDownloadPlaylistEntry(t *testing.T) {
+	defer leakChecks(t)()
+	// Download file by specifying the playlist index
+	stderrBuf := &bytes.Buffer{}
+	r, err := goutubedl.New(context.Background(), playlistRawURL, goutubedl.Options{
+		StderrFn: func(cmd *exec.Cmd) io.Writer {
+			return stderrBuf
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expectedTitle := "Kindred Phenomena"
+	if r.Info.Title != expectedTitle {
+		t.Errorf("expected title %q got %q", expectedTitle, r.Info.Title)
+	}
+
+	expectedEntries := 8
+	if len(r.Info.Entries) != expectedEntries {
+		t.Errorf("expected %d entries got %d", expectedEntries, len(r.Info.Entries))
+	}
+
+	expectedTitleOne := "B1 Mattheis - Ben M"
+	playlistIndex := 2
+	if r.Info.Entries[playlistIndex].Title != expectedTitleOne {
+		t.Errorf("expected title %q got %q", expectedTitleOne, r.Info.Entries[playlistIndex].Title)
+	}
+
+	dr, err := r.DownloadWithOptions(context.Background(), goutubedl.DownloadOptions{
+		PlaylistIndex: int(r.Info.Entries[playlistIndex].PlaylistIndex),
+		Filter:        r.Info.Entries[playlistIndex].Formats[0].FormatID,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	playlistBuf := &bytes.Buffer{}
+	n, err := io.Copy(playlistBuf, dr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dr.Close()
+
+	if n != int64(playlistBuf.Len()) {
+		t.Errorf("copy n not equal to download buffer: %d!=%d", n, playlistBuf.Len())
+	}
+
+	if n < 10000 {
+		t.Errorf("should have copied at least 10000 bytes: %d", n)
+	}
+
+	if !strings.Contains(stderrBuf.String(), "Destination") {
+		t.Errorf("did not find expected log message on stderr: %q", stderrBuf.String())
+	}
+
+	// Download the same file but with the direct link
+	url := "https://soundcloud.com/mattheis/b1-mattheis-ben-m"
+	stderrBuf = &bytes.Buffer{}
+	r, err = goutubedl.New(context.Background(), url, goutubedl.Options{
+		StderrFn: func(cmd *exec.Cmd) io.Writer {
+			return stderrBuf
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if r.Info.Title != expectedTitleOne {
+		t.Errorf("expected title %q got %q", expectedTitleOne, r.Info.Title)
+	}
+
+	expectedEntries = 0
+	if len(r.Info.Entries) != expectedEntries {
+		t.Errorf("expected %d entries got %d", expectedEntries, len(r.Info.Entries))
+	}
+
+	dr, err = r.Download(context.Background(), r.Info.Formats[0].FormatID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	directLinkBuf := &bytes.Buffer{}
+	n, err = io.Copy(directLinkBuf, dr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dr.Close()
+
+	if n != int64(directLinkBuf.Len()) {
+		t.Errorf("copy n not equal to download buffer: %d!=%d", n, directLinkBuf.Len())
+	}
+
+	if n < 10000 {
+		t.Errorf("should have copied at least 10000 bytes: %d", n)
+	}
+
+	if !strings.Contains(stderrBuf.String(), "Destination") {
+		t.Errorf("did not find expected log message on stderr: %q", stderrBuf.String())
+	}
+
+	if directLinkBuf.Len() != playlistBuf.Len() {
+		t.Errorf("not the same content size between the playlist index entry and the direct link entry: %d != %d", playlistBuf.Len(), directLinkBuf.Len())
+	}
+
+	if !bytes.Equal(directLinkBuf.Bytes(), playlistBuf.Bytes()) {
+		t.Error("not the same content between the playlist index entry and the direct link entry")
+	}
+}