Add a cache for gallery thumbnails (#496)

pkg/api/cache_thumbs.go

@@ -0,0 +1,72 @@
+package api
+
+import (
+	"github.com/stashapp/stash/pkg/logger"
+	"github.com/stashapp/stash/pkg/manager/paths"
+	"github.com/stashapp/stash/pkg/models"
+	"github.com/stashapp/stash/pkg/utils"
+	"io/ioutil"
+)
+
+type thumbBuffer struct {
+	path string
+	dir  string
+	data []byte
+}
+
+func newCacheThumb(dir string, path string, data []byte) *thumbBuffer {
+	t := thumbBuffer{dir: dir, path: path, data: data}
+	return &t
+}
+
+var writeChan chan *thumbBuffer
+var touchChan chan *string
+
+func startThumbCache() { // TODO add extra wait, close chan code if/when stash gets a stop mode
+
+	writeChan = make(chan *thumbBuffer, 20)
+	go thumbnailCacheWriter()
+}
+
+//serialize file writes to avoid race conditions
+func thumbnailCacheWriter() {
+
+	for thumb := range writeChan {
+		exists, _ := utils.FileExists(thumb.path)
+		if !exists {
+			err := utils.WriteFile(thumb.path, thumb.data)
+			if err != nil {
+				logger.Errorf("Write error for thumbnail %s: %s ", thumb.path, err)
+			}
+		}
+	}
+
+}
+
+// get thumbnail from cache, otherwise create it and store to cache
+func cacheGthumb(gallery *models.Gallery, index int, width int) []byte {
+	thumbPath := paths.GetGthumbPath(gallery.Checksum, index, width)
+	exists, _ := utils.FileExists(thumbPath)
+	if exists { // if thumbnail exists in cache return that
+		content, err := ioutil.ReadFile(thumbPath)
+		if err == nil {
+			return content
+		} else {
+			logger.Errorf("Read Error for file %s : %s", thumbPath, err)
+		}
+
+	}
+	data := gallery.GetThumbnail(index, width)
+	thumbDir := paths.GetGthumbDir(gallery.Checksum)
+	t := newCacheThumb(thumbDir, thumbPath, data)
+	writeChan <- t // write the file to cache
+	return data
+}
+
+// create all thumbs for a given gallery
+func CreateGthumbs(gallery *models.Gallery) {
+	count := gallery.ImageCount()
+	for i := 0; i < count; i++ {
+		cacheGthumb(gallery, i, models.DefaultGthumbWidth)
+	}
+}

pkg/api/resolver_mutation_configure.go

@@ -38,6 +38,13 @@ func (r *mutationResolver) ConfigureGeneral(ctx context.Context, input models.Co
 		config.Set(config.Generated, input.GeneratedPath)
 	}
 
+	if input.CachePath != nil {
+		if err := utils.EnsureDir(*input.CachePath); err != nil {
+			return makeConfigGeneralResult(), err
+		}
+		config.Set(config.Cache, input.CachePath)
+	}
+
 	if input.MaxTranscodeSize != nil {
 		config.Set(config.MaxTranscodeSize, input.MaxTranscodeSize.String())
 	}

pkg/api/resolver_mutation_metadata.go

@@ -23,7 +23,7 @@ func (r *mutationResolver) MetadataExport(ctx context.Context) (string, error) {
 }
 
 func (r *mutationResolver) MetadataGenerate(ctx context.Context, input models.GenerateMetadataInput) (string, error) {
-	manager.GetInstance().Generate(input.Sprites, input.Previews, input.Markers, input.Transcodes)
+	manager.GetInstance().Generate(input.Sprites, input.Previews, input.Markers, input.Transcodes, input.Thumbnails)
 	return "todo", nil
 }
 

pkg/api/resolver_query_configuration.go

@@ -45,6 +45,7 @@ func makeConfigGeneralResult() *models.ConfigGeneralResult {
 		Stashes:                   config.GetStashPaths(),
 		DatabasePath:              config.GetDatabasePath(),
 		GeneratedPath:             config.GetGeneratedPath(),
+		CachePath:                 config.GetCachePath(),
 		MaxTranscodeSize:          &maxTranscodeSize,
 		MaxStreamingTranscodeSize: &maxStreamingTranscodeSize,
 		ForceMkv:                  config.GetForceMKV(),

pkg/api/routes_gallery.go

@@ -23,11 +23,15 @@ func (rs galleryRoutes) Routes() chi.Router {
 
 func (rs galleryRoutes) File(w http.ResponseWriter, r *http.Request) {
 	gallery := r.Context().Value(galleryKey).(*models.Gallery)
+	if gallery == nil {
+		http.Error(w, http.StatusText(404), 404)
+		return
+	}
 	fileIndex, _ := strconv.Atoi(chi.URLParam(r, "fileIndex"))
 	thumb := r.URL.Query().Get("thumb")
 	w.Header().Add("Cache-Control", "max-age=604800000") // 1 Week
 	if thumb == "true" {
-		_, _ = w.Write(gallery.GetThumbnail(fileIndex, 200))
+		_, _ = w.Write(cacheGthumb(gallery, fileIndex, models.DefaultGthumbWidth))
 	} else if thumb == "" {
 		_, _ = w.Write(gallery.GetImage(fileIndex))
 	} else {
@@ -36,7 +40,7 @@ func (rs galleryRoutes) File(w http.ResponseWriter, r *http.Request) {
 			http.Error(w, http.StatusText(400), 400)
 			return
 		}
-		_, _ = w.Write(gallery.GetThumbnail(fileIndex, int(width)))
+		_, _ = w.Write(cacheGthumb(gallery, fileIndex, int(width)))
 	}
 }
 

pkg/api/server.go

@@ -245,6 +245,7 @@ func Start() {
 		http.Redirect(w, r, "/", 301)
 	})
 
+	startThumbCache()
 	// Serve the web app
 	r.HandleFunc("/*", func(w http.ResponseWriter, r *http.Request) {
 		ext := path.Ext(r.URL.Path)