feat: filebrowser with encfs

http/preview.go

@@ -0,0 +1,157 @@
+//go:generate go-enum --sql --marshal --names --file $GOFILE
+package http
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/gorilla/mux"
+
+	"github.com/filebrowser/filebrowser/v2/files"
+	"github.com/filebrowser/filebrowser/v2/img"
+)
+
+/*
+ENUM(
+thumb
+big
+)
+*/
+type PreviewSize int
+
+type ImgService interface {
+	FormatFromExtension(ext string) (img.Format, error)
+	Resize(ctx context.Context, in io.Reader, width, height int, out io.Writer, options ...img.Option) error
+}
+
+type FileCache interface {
+	Store(ctx context.Context, key string, value []byte) error
+	Load(ctx context.Context, key string) ([]byte, bool, error)
+	Delete(ctx context.Context, key string) error
+}
+
+func previewHandler(imgSvc ImgService, fileCache FileCache, enableThumbnails, resizePreview bool) handleFunc {
+	return withUser(func(w http.ResponseWriter, r *http.Request, d *data) (int, error) {
+		if !d.user.Perm.Download {
+			return http.StatusAccepted, nil
+		}
+		vars := mux.Vars(r)
+
+		previewSize, err := ParsePreviewSize(vars["size"])
+		if err != nil {
+			return http.StatusBadRequest, err
+		}
+
+		file, err := files.NewFileInfo(&files.FileOptions{
+			Fs:         d.user.Fs,
+			Path:       "/" + vars["path"],
+			Modify:     d.user.Perm.Modify,
+			Expand:     true,
+			ReadHeader: d.server.TypeDetectionByHeader,
+			Checker:    d,
+		})
+		if err != nil {
+			return errToStatus(err), err
+		}
+
+		setContentDisposition(w, r, file)
+
+		switch file.Type {
+		case "image":
+			return handleImagePreview(w, r, imgSvc, fileCache, file, previewSize, enableThumbnails, resizePreview)
+		default:
+			return http.StatusNotImplemented, fmt.Errorf("can't create preview for %s type", file.Type)
+		}
+	})
+}
+
+func handleImagePreview(
+	w http.ResponseWriter,
+	r *http.Request,
+	imgSvc ImgService,
+	fileCache FileCache,
+	file *files.FileInfo,
+	previewSize PreviewSize,
+	enableThumbnails, resizePreview bool,
+) (int, error) {
+	if (previewSize == PreviewSizeBig && !resizePreview) ||
+		(previewSize == PreviewSizeThumb && !enableThumbnails) {
+		return rawFileHandler(w, r, file)
+	}
+
+	format, err := imgSvc.FormatFromExtension(file.Extension)
+	// Unsupported extensions directly return the raw data
+	if errors.Is(err, img.ErrUnsupportedFormat) || format == img.FormatGif {
+		return rawFileHandler(w, r, file)
+	}
+	if err != nil {
+		return errToStatus(err), err
+	}
+
+	cacheKey := previewCacheKey(file, previewSize)
+	resizedImage, ok, err := fileCache.Load(r.Context(), cacheKey)
+	if err != nil {
+		return errToStatus(err), err
+	}
+	if !ok {
+		resizedImage, err = createPreview(imgSvc, fileCache, file, previewSize)
+		if err != nil {
+			return errToStatus(err), err
+		}
+	}
+
+	w.Header().Set("Cache-Control", "private")
+	http.ServeContent(w, r, file.Name, file.ModTime, bytes.NewReader(resizedImage))
+
+	return 0, nil
+}
+
+func createPreview(imgSvc ImgService, fileCache FileCache,
+	file *files.FileInfo, previewSize PreviewSize) ([]byte, error) {
+	fd, err := file.Fs.Open(file.Path)
+	if err != nil {
+		return nil, err
+	}
+	defer fd.Close()
+
+	var (
+		width   int
+		height  int
+		options []img.Option
+	)
+
+	switch {
+	case previewSize == PreviewSizeBig:
+		width = 1080
+		height = 1080
+		options = append(options, img.WithMode(img.ResizeModeFit), img.WithQuality(img.QualityMedium))
+	case previewSize == PreviewSizeThumb:
+		width = 256
+		height = 256
+		options = append(options, img.WithMode(img.ResizeModeFill), img.WithQuality(img.QualityLow), img.WithFormat(img.FormatJpeg))
+	default:
+		return nil, img.ErrUnsupportedFormat
+	}
+
+	buf := &bytes.Buffer{}
+	if err := imgSvc.Resize(context.Background(), fd, width, height, buf, options...); err != nil {
+		return nil, err
+	}
+
+	go func() {
+		cacheKey := previewCacheKey(file, previewSize)
+		if err := fileCache.Store(context.Background(), cacheKey, buf.Bytes()); err != nil {
+			fmt.Printf("failed to cache resized image: %v", err)
+		}
+	}()
+
+	return buf.Bytes(), nil
+}
+
+func previewCacheKey(f *files.FileInfo, previewSize PreviewSize) string {
+	return fmt.Sprintf("%x%x%x", f.RealPath(), f.ModTime.Unix(), previewSize)
+}