initial support for playlist modifiers

supported modifiers are --playlist-start, --playlist-end, --playlist-reverse, --max-downloads

frontend/src/assets/i18n/en_US.yaml

@@ -31,7 +31,7 @@ keys:
   splashText: No active downloads
   archiveTitle: Archive
   clipboardAction: Copied URL to clipboard
-  playlistCheckbox: Download playlist (it will take time, after submitting you may close this window)
+  playlistCheckbox: Download playlist
   restartAppMessage: Needs a page reload to take effect
   servedFromReverseProxyCheckbox: Is behind a reverse proxy
   urlBase: URL base, for reverse proxy support (subdir), defaults to empty

server/common/types.go

@@ -0,0 +1,18 @@
+package common
+
+import "time"
+
+// Used to deser the yt-dlp -J output
+type DownloadInfo struct {
+	URL         string    `json:"url"`
+	Title       string    `json:"title"`
+	Thumbnail   string    `json:"thumbnail"`
+	Resolution  string    `json:"resolution"`
+	Size        int32     `json:"filesize_approx"`
+	VCodec      string    `json:"vcodec"`
+	ACodec      string    `json:"acodec"`
+	Extension   string    `json:"ext"`
+	OriginalURL string    `json:"original_url"`
+	FileName    string    `json:"filename"`
+	CreatedAt   time.Time `json:"created_at"`
+}

server/internal/common_types.go

@@ -1,6 +1,8 @@
 package internal
 
-import "time"
+import (
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/common"
+)
 
 // Used to unmarshall yt-dlp progress
 type ProgressTemplate struct {
@@ -29,29 +31,14 @@ type DownloadProgress struct {
 	ETA        float64 `json:"eta"`
 }
 
-// Used to deser the yt-dlp -J output
-type DownloadInfo struct {
-	URL         string    `json:"url"`
-	Title       string    `json:"title"`
-	Thumbnail   string    `json:"thumbnail"`
-	Resolution  string    `json:"resolution"`
-	Size        int32     `json:"filesize_approx"`
-	VCodec      string    `json:"vcodec"`
-	ACodec      string    `json:"acodec"`
-	Extension   string    `json:"ext"`
-	OriginalURL string    `json:"original_url"`
-	FileName    string    `json:"filename"`
-	CreatedAt   time.Time `json:"created_at"`
-}
-
 // struct representing the response sent to the client
 // as JSON-RPC result field
 type ProcessResponse struct {
-	Id       string           `json:"id"`
-	Progress DownloadProgress `json:"progress"`
-	Info     DownloadInfo     `json:"info"`
-	Output   DownloadOutput   `json:"output"`
-	Params   []string         `json:"params"`
+	Id       string              `json:"id"`
+	Progress DownloadProgress    `json:"progress"`
+	Info     common.DownloadInfo `json:"info"`
+	Output   DownloadOutput      `json:"output"`
+	Params   []string            `json:"params"`
 }
 
 // struct representing the current status of the memoryDB

server/internal/playlist.go

@@ -9,20 +9,18 @@ import (
 	"strings"
 	"time"
 
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/common"
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/config"
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/playlist"
 )
 
-type metadata struct {
-	Entries       []DownloadInfo `json:"entries"`
-	Count         int            `json:"playlist_count"`
-	PlaylistTitle string         `json:"title"`
-	Type          string         `json:"_type"`
-}
-
 func PlaylistDetect(req DownloadRequest, mq *MessageQueue, db *MemoryDB) error {
+	params := append(req.Params, "--flat-playlist", "-J")
+	urlWithParams := append([]string{req.URL}, params...)
+
 	var (
 		downloader = config.Instance().DownloaderPath
-		cmd        = exec.Command(downloader, req.URL, "--flat-playlist", "-J")
+		cmd        = exec.Command(downloader, urlWithParams...)
 	)
 
 	stdout, err := cmd.StdoutPipe()
@@ -30,7 +28,7 @@ func PlaylistDetect(req DownloadRequest, mq *MessageQueue, db *MemoryDB) error {
 		return err
 	}
 
-	var m metadata
+	var m playlist.Metadata
 
 	if err := cmd.Start(); err != nil {
 		return err
@@ -53,12 +51,20 @@ func PlaylistDetect(req DownloadRequest, mq *MessageQueue, db *MemoryDB) error {
 	}
 
 	if m.Type == "playlist" {
-		entries := slices.CompactFunc(slices.Compact(m.Entries), func(a DownloadInfo, b DownloadInfo) bool {
+		entries := slices.CompactFunc(slices.Compact(m.Entries), func(a common.DownloadInfo, b common.DownloadInfo) bool {
 			return a.URL == b.URL
 		})
 
+		entries = slices.DeleteFunc(entries, func(e common.DownloadInfo) bool {
+			return strings.Contains(e.URL, "list=")
+		})
+
 		slog.Info("playlist detected", slog.String("url", req.URL), slog.Int("count", len(entries)))
 
+		if err := playlist.ApplyModifiers(&entries, req.Params); err != nil {
+			return err
+		}
+
 		for i, meta := range entries {
 			// detect playlist title from metadata since each playlist entry will be
 			// treated as an individual download
@@ -87,6 +93,8 @@ func PlaylistDetect(req DownloadRequest, mq *MessageQueue, db *MemoryDB) error {
 			db.Set(proc)
 			mq.Publish(proc)
 		}
+
+		return nil
 	}
 
 	proc := &Process{

server/internal/process.go

@@ -19,6 +19,7 @@ import (
 	"time"
 
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/archiver"
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/common"
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/config"
 )
 
@@ -50,7 +51,7 @@ type Process struct {
 	Livestream bool
 	AutoRemove bool
 	Params     []string
-	Info       DownloadInfo
+	Info       common.DownloadInfo
 	Progress   DownloadProgress
 	Output     DownloadOutput
 	proc       *os.Process
@@ -302,7 +303,7 @@ func (p *Process) GetFileName(o *DownloadOutput) error {
 
 func (p *Process) SetPending() {
 	// Since video's title isn't available yet, fill in with the URL.
-	p.Info = DownloadInfo{
+	p.Info = common.DownloadInfo{
 		URL:       p.Url,
 		Title:     p.Url,
 		CreatedAt: time.Now(),
@@ -334,7 +335,7 @@ func (p *Process) SetMetadata() error {
 		return err
 	}
 
-	info := DownloadInfo{
+	info := common.DownloadInfo{
 		URL:       p.Url,
 		CreatedAt: time.Now(),
 	}

server/playlist/modifiers.go

@@ -0,0 +1,86 @@
+package playlist
+
+import (
+	"slices"
+	"strconv"
+
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/common"
+)
+
+/*
+	Applicable modifiers
+
+				full									|		   short		  |					description
+	---------------------------------------------------------------------------------
+	--playlist-start NUMBER     |    -I NUMBER:	  |	  discard first N entries
+	--playlist-end NUMBER       |    -I :NUMBER   |   discard last N entries
+	--playlist-reverse          |    -I ::-1			|   self explanatory
+	--max-downloads NUMBER      |                 |   stops after N completed downloads
+*/
+
+func ApplyModifiers(entries *[]common.DownloadInfo, args []string) error {
+	for i, modifier := range args {
+		switch modifier {
+		case "--playlist-start":
+			return playlistStart(i, modifier, args, entries)
+
+		case "--playlist-end":
+			return playlistEnd(i, modifier, args, entries)
+
+		case "--max-downloads":
+			return maxDownloads(i, modifier, args, entries)
+
+		case "--playlist-reverse":
+			slices.Reverse(*entries)
+			return nil
+		}
+	}
+	return nil
+}
+
+func playlistStart(i int, modifier string, args []string, entries *[]common.DownloadInfo) error {
+	if !guard(i, len(modifier)) {
+		return nil
+	}
+
+	n, err := strconv.Atoi(args[i+1])
+	if err != nil {
+		return err
+	}
+
+	*entries = (*entries)[n:]
+
+	return nil
+}
+
+func playlistEnd(i int, modifier string, args []string, entries *[]common.DownloadInfo) error {
+	if !guard(i, len(modifier)) {
+		return nil
+	}
+
+	n, err := strconv.Atoi(args[i+1])
+	if err != nil {
+		return err
+	}
+
+	*entries = (*entries)[:n]
+
+	return nil
+}
+
+func maxDownloads(i int, modifier string, args []string, entries *[]common.DownloadInfo) error {
+	if !guard(i, len(modifier)) {
+		return nil
+	}
+
+	n, err := strconv.Atoi(args[i+1])
+	if err != nil {
+		return err
+	}
+
+	*entries = (*entries)[0:n]
+
+	return nil
+}
+
+func guard(i, len int) bool { return i+1 < len-1 }

server/playlist/types.go

@@ -0,0 +1,10 @@
+package playlist
+
+import "github.com/marcopiovanello/yt-dlp-web-ui/v3/server/common"
+
+type Metadata struct {
+	Entries       []common.DownloadInfo `json:"entries"`
+	Count         int                   `json:"playlist_count"`
+	PlaylistTitle string                `json:"title"`
+	Type          string                `json:"_type"`
+}