Implement episode downloader

pkg/ytdl/ytdl.go

@@ -0,0 +1,107 @@
+package ytdl
+
+import (
+	"context"
+	"os/exec"
+	"time"
+
+	"github.com/pkg/errors"
+	log "github.com/sirupsen/logrus"
+
+	"github.com/mxpv/podsync/pkg/config"
+	"github.com/mxpv/podsync/pkg/model"
+)
+
+const DownloadTimeout = 10 * time.Minute
+
+type YoutubeDl struct{}
+
+func New(ctx context.Context) (*YoutubeDl, error) {
+	ytdl := &YoutubeDl{}
+
+	// Make sure youtube-dl exists
+	version, err := ytdl.exec(ctx, "--version")
+	if err != nil {
+		return nil, errors.Wrap(err, "could not find youtube-dl")
+	}
+
+	log.Infof("using youtube-dl %s", version)
+
+	// Make sure ffmpeg exists
+	output, err := exec.CommandContext(ctx, "ffmpeg", "-version").CombinedOutput()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not find ffmpeg")
+	}
+
+	log.Infof("using ffmpeg %s", output)
+
+	return ytdl, nil
+}
+
+func (dl YoutubeDl) Download(ctx context.Context, feedConfig *config.Feed, url string, destPath string) (string, error) {
+	if feedConfig.Format == model.FormatAudio {
+		// Audio
+		if feedConfig.Quality == model.QualityHigh {
+			// High quality audio (encoded to mp3)
+			return dl.exec(ctx,
+				"--extract-audio",
+				"--audio-format",
+				"mp3",
+				"--format",
+				"bestaudio",
+				"--output",
+				destPath,
+				url,
+			)
+		} else {
+			// Low quality audio (encoded to mp3)
+			return dl.exec(ctx,
+				"--extract-audio",
+				"--audio-format",
+				"mp3",
+				"--format",
+				"worstaudio",
+				"--output",
+				destPath,
+				url,
+			)
+		}
+	} else {
+		/*
+			Video
+		*/
+		if feedConfig.Quality == model.QualityHigh {
+			// High quality
+			return dl.exec(ctx,
+				"--format",
+				"bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best",
+				"--output",
+				destPath,
+				url,
+			)
+		} else {
+			// Low quality
+			return dl.exec(ctx,
+				"--format",
+				"worstvideo[ext=mp4]+worstaudio[ext=m4a]/worst[ext=mp4]/worst",
+				"--output",
+				destPath,
+				url,
+			)
+		}
+	}
+}
+
+func (YoutubeDl) exec(ctx context.Context, args ...string) (string, error) {
+	ctx, cancel := context.WithTimeout(ctx, DownloadTimeout)
+	defer cancel()
+
+	cmd := exec.CommandContext(ctx, "youtube-dl", args...)
+
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		return string(output), errors.Wrap(err, "failed to execute youtube-dl")
+	}
+
+	return string(output), nil
+}