download cmd handle playlist & video

Author: itscaro

client.go

@@ -72,7 +72,7 @@ func (c *Client) GetPlaylist(url string) (*Playlist, error) {
 // for these videos. Playlist entries cannot be downloaded, as they lack all the required metadata, but
 // can be used to enumerate all IDs, Authors, Titles, etc.
 func (c *Client) GetPlaylistContext(ctx context.Context, url string) (*Playlist, error) {
-	id, err := extractPlaylistID(url)
+	id, err := ExtractPlaylistID(url)
 	if err != nil {
 		return nil, fmt.Errorf("extractPlaylistID failed: %w", err)
 	}

cmd/youtubedr/download.go

@@ -7,17 +7,57 @@ import (
 	"os/exec"
 	"strings"
 
+	"github.com/kkdai/youtube/v2"
 	"github.com/spf13/cobra"
 )
 
+var (
+	errNotID = fmt.Errorf("cannot detect ID in given input")
+)
+
 // downloadCmd represents the download command
 var downloadCmd = &cobra.Command{
 	Use:     "download",
-	Short:   "Downloads a video from youtube",
+	Short:   "Downloads a video or a playlist from youtube",
 	Example: `youtubedr -o "Campaign Diary".mp4 https://www.youtube.com/watch\?v\=XbNghLqsVwU`,
 	Args:    cobra.ExactArgs(1),
 	Run: func(cmd *cobra.Command, args []string) {
-		exitOnError(download(args[0]))
+		if playlistID, err := youtube.ExtractPlaylistID(args[0]); err != nil {
+			if videoID, err := youtube.ExtractVideoID(args[0]); err != nil {
+				exitOnError(errNotID)
+			} else {
+				log.Printf(
+					"download video %s to directory %s\n",
+					videoID,
+					outputDir,
+				)
+				exitOnError(download(videoID))
+			}
+		} else {
+			if playlist, err := getDownloader().GetPlaylist(playlistID); err != nil {
+				exitOnError(err)
+			} else {
+				log.Printf(
+					"download %d videos from playlist %s to directory %s\n",
+					len(playlist.Videos),
+					playlist.ID,
+					outputDir,
+				)
+				var errors []error
+				outputFileOrigin := outputFile
+				for i, v := range playlist.Videos {
+					if len(outputFileOrigin) != 0 {
+						outputFile = fmt.Sprintf("%s-%d", outputFile, i)
+					}
+					if err := download(v.ID); err != nil {
+						errors = append(errors, err)
+					}
+				}
+				if len(errors) > 0 {
+					exitOnErrors(errors)
+				}
+			}
+		}
 	},
 }
 
@@ -30,7 +70,7 @@ var (
 func init() {
 	rootCmd.AddCommand(downloadCmd)
 
-	downloadCmd.Flags().StringVarP(&outputFile, "filename", "o", "", "The output file, the default is genated by the video title.")
+	downloadCmd.Flags().StringVarP(&outputFile, "filename", "o", "", "The output file, the default is generated from the video title.")
 	downloadCmd.Flags().StringVarP(&outputDir, "directory", "d", ".", "The output directory.")
 	addQualityFlag(downloadCmd.Flags())
 	addMimeTypeFlag(downloadCmd.Flags())
@@ -42,8 +82,6 @@ func download(id string) error {
 		return err
 	}
 
-	log.Println("download to directory", outputDir)
-
 	if strings.HasPrefix(outputQuality, "hd") {
 		if err := checkFFMPEG(); err != nil {
 			return err

cmd/youtubedr/main.go

@@ -15,3 +15,12 @@ func exitOnError(err error) {
 		os.Exit(1)
 	}
 }
+
+func exitOnErrors(errors []error) {
+	if len(errors) != 0 {
+		for _, err := range errors {
+			fmt.Fprintln(os.Stderr, err)
+		}
+		os.Exit(1)
+	}
+}

playlist.go

@@ -39,7 +39,7 @@ type PlaylistEntry struct {
 	Duration time.Duration
 }
 
-func extractPlaylistID(url string) (string, error) {
+func ExtractPlaylistID(url string) (string, error) {
 	if playlistIDRegex.Match([]byte(url)) {
 		return url, nil
 	}