WIP - pre-download audio files for queued tracks

backend/app.go

@@ -44,6 +44,7 @@ type App struct {
 	Config          *Config
 	ServerManager   *ServerManager
 	ImageManager    *ImageManager
+	AudioCache      *AudioCache
 	PlaybackManager *PlaybackManager
 	LocalPlayer     *mpv.Player
 	UpdateChecker   UpdateChecker
@@ -142,8 +143,13 @@ func StartupApp(appName, displayAppName, appVersion, appVersionTag, latestReleas
 	}
 
 	a.ServerManager = NewServerManager(appName, appVersion, a.Config, !portableMode && a.Config.Application.EnablePasswordStorage)
-	a.PlaybackManager = NewPlaybackManager(a.bgrndCtx, a.ServerManager, a.LocalPlayer, &a.Config.Playback, &a.Config.Scrobbling, &a.Config.Transcoding, &a.Config.Application)
 	a.ImageManager = NewImageManager(a.bgrndCtx, a.ServerManager, cacheDir)
+	ac, err := NewAudioCache(a.bgrndCtx, a.ServerManager, filepath.Join(cacheDir, "audio"))
+	if err != nil {
+		log.Printf("failed to create audio cache: %s", err.Error())
+	}
+	a.AudioCache = ac
+	a.PlaybackManager = NewPlaybackManager(a.bgrndCtx, a.ServerManager, a.LocalPlayer, &a.Config.Playback, &a.Config.Scrobbling, &a.Config.Transcoding, &a.Config.Application)
 	a.Config.Application.MaxImageCacheSizeMB = clamp(a.Config.Application.MaxImageCacheSizeMB, 1, 500)
 	a.ImageManager.SetMaxOnDiskCacheSizeBytes(int64(a.Config.Application.MaxImageCacheSizeMB) * 1_048_576)
 	a.ServerManager.SetPrefetchAlbumCoverCallback(func(coverID string) {
@@ -475,6 +481,9 @@ func (a *App) Shutdown() {
 	}
 	a.PlaybackManager.DisableCallbacks()
 	a.PlaybackManager.Shutdown() // will trigger scrobble check
+	if a.AudioCache != nil {
+		a.AudioCache.Shutdown()
+	}
 	a.cancel()
 	a.LocalPlayer.Destroy()
 }

sharedutil/sharedutil.go

@@ -1,6 +1,12 @@
 package sharedutil
 
 import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+
 	"github.com/dweymouth/supersonic/backend/mediaprovider"
 )
 
@@ -133,3 +139,50 @@ func ReorderItems[T any](items []T, idxToMove []int, insertIdx int) []T {
 
 	return newItems
 }
+
+// DownloadFileWithContext downloads a file from the specified URL and saves it to destPath.
+// It respects the provided context and will cancel the request and cleanup if context is done.
+// Returns an error if an error other than cancellation occurs, and returns true IFF the file was completely downloaded.
+func DownloadFileWithContext(ctx context.Context, url string, destPath string) (bool, error) {
+	// Create HTTP request with context
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return false, fmt.Errorf("creating request: %w", err)
+	}
+
+	// Perform the request
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return false, fmt.Errorf("performing request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	// Check for non-200 status codes
+	if resp.StatusCode != http.StatusOK {
+		return false, fmt.Errorf("bad status: %s", resp.Status)
+	}
+
+	// Create the destination file
+	out, err := os.Create(destPath)
+	if err != nil {
+		return false, fmt.Errorf("creating file: %w", err)
+	}
+	defer out.Close()
+
+	_, err = io.Copy(out, resp.Body)
+
+	select {
+	case <-ctx.Done():
+		// Cancelled, delete partial file
+		out.Close()
+		os.Remove(destPath)
+		return false, nil
+	default:
+		if err != nil {
+			os.Remove(destPath)
+			return false, fmt.Errorf("error copying data: %w", err)
+		}
+	}
+
+	return true, nil
+}