feat: cache resized images

cmd/root.go

@@ -13,16 +13,17 @@ import (
 	"strings"
 	"syscall"
 
-	"github.com/filebrowser/filebrowser/v2/img"
-
 	homedir "github.com/mitchellh/go-homedir"
+	"github.com/spf13/afero"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	v "github.com/spf13/viper"
 	lumberjack "gopkg.in/natefinch/lumberjack.v2"
 
 	"github.com/filebrowser/filebrowser/v2/auth"
+	"github.com/filebrowser/filebrowser/v2/diskcache"
 	fbhttp "github.com/filebrowser/filebrowser/v2/http"
+	"github.com/filebrowser/filebrowser/v2/img"
 	"github.com/filebrowser/filebrowser/v2/settings"
 	"github.com/filebrowser/filebrowser/v2/storage"
 	"github.com/filebrowser/filebrowser/v2/users"
@@ -58,6 +59,7 @@ func addServerFlags(flags *pflag.FlagSet) {
 	flags.StringP("root", "r", ".", "root to prepend to relative paths")
 	flags.String("socket", "", "socket to listen to (cannot be used with address, port, cert nor key flags)")
 	flags.StringP("baseurl", "b", "", "base url")
+	flags.String("cache-dir", "", "file cache directory (disabled if empty)")
 	flags.Int("img-processors", 4, "image processors count")
 	flags.Bool("disable-thumbnails", false, "disable image thumbnails")
 	flags.Bool("disable-preview-resize", false, "disable resize of image previews")
@@ -116,6 +118,16 @@ user created with the credentials from options "username" and "password".`,
 		}
 		imgSvc := img.New(workersCount)
 
+		var fileCache diskcache.Interface = diskcache.NewNoOp()
+		cacheDir, err := cmd.Flags().GetString("cache-dir")
+		checkErr(err)
+		if cacheDir != "" {
+			if err := os.MkdirAll(cacheDir, 0700); err != nil { //nolint:govet
+				log.Fatalf("can't make directory %s: %s", cacheDir, err)
+			}
+			fileCache = diskcache.New(afero.NewOsFs(), cacheDir)
+		}
+
 		server := getRunParams(cmd.Flags(), d.store)
 		setupLog(server.Log)
 
@@ -145,7 +157,7 @@ user created with the credentials from options "username" and "password".`,
 		signal.Notify(sigc, os.Interrupt, syscall.SIGTERM)
 		go cleanupHandler(listener, sigc)
 
-		handler, err := fbhttp.NewHandler(imgSvc, d.store, server)
+		handler, err := fbhttp.NewHandler(imgSvc, fileCache, d.store, server)
 		checkErr(err)
 
 		defer listener.Close()

diskcache/cache.go

@@ -0,0 +1,11 @@
+package diskcache
+
+import (
+	"context"
+)
+
+type Interface interface {
+	Store(ctx context.Context, key string, value []byte) error
+	Load(ctx context.Context, key string) (value []byte, exist bool, err error)
+	Delete(ctx context.Context, key string) error
+}

diskcache/file_cache.go

@@ -0,0 +1,110 @@
+package diskcache
+
+import (
+	"context"
+	"crypto/sha1" //nolint:gosec
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sync"
+
+	"github.com/spf13/afero"
+)
+
+type FileCache struct {
+	fs afero.Fs
+
+	// granular locks
+	scopedLocks struct {
+		sync.Mutex
+		sync.Once
+		locks map[string]sync.Locker
+	}
+}
+
+func New(fs afero.Fs, root string) *FileCache {
+	return &FileCache{
+		fs: afero.NewBasePathFs(fs, root),
+	}
+}
+
+func (f *FileCache) Store(ctx context.Context, key string, value []byte) error {
+	mu := f.getScopedLocks(key)
+	mu.Lock()
+	defer mu.Unlock()
+
+	fileName := f.getFileName(key)
+	if err := f.fs.MkdirAll(filepath.Dir(fileName), 0700); err != nil {
+		return err
+	}
+
+	if err := afero.WriteFile(f.fs, fileName, value, 0700); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (f *FileCache) Load(ctx context.Context, key string) (value []byte, exist bool, err error) {
+	r, ok, err := f.open(key)
+	if err != nil || !ok {
+		return nil, ok, err
+	}
+	defer r.Close()
+
+	value, err = ioutil.ReadAll(r)
+	if err != nil {
+		return nil, false, err
+	}
+	return value, true, nil
+}
+
+func (f *FileCache) Delete(ctx context.Context, key string) error {
+	mu := f.getScopedLocks(key)
+	mu.Lock()
+	defer mu.Unlock()
+
+	fileName := f.getFileName(key)
+	if err := f.fs.Remove(fileName); err != nil && err != os.ErrNotExist {
+		return err
+	}
+	return nil
+}
+
+func (f *FileCache) open(key string) (afero.File, bool, error) {
+	fileName := f.getFileName(key)
+	file, err := f.fs.Open(fileName)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return nil, false, nil
+		}
+		return nil, false, err
+	}
+
+	return file, true, nil
+}
+
+// getScopedLocks pull lock from the map if found or create a new one
+func (f *FileCache) getScopedLocks(key string) (lock sync.Locker) {
+	f.scopedLocks.Do(func() { f.scopedLocks.locks = map[string]sync.Locker{} })
+
+	f.scopedLocks.Lock()
+	lock, ok := f.scopedLocks.locks[key]
+	if !ok {
+		lock = &sync.Mutex{}
+		f.scopedLocks.locks[key] = lock
+	}
+	f.scopedLocks.Unlock()
+
+	return lock
+}
+
+func (f *FileCache) getFileName(key string) string {
+	hasher := sha1.New() //nolint:gosec
+	_, _ = hasher.Write([]byte(key))
+	hash := hex.EncodeToString(hasher.Sum(nil))
+	return fmt.Sprintf("%s/%s/%s", hash[:1], hash[1:3], hash)
+}

diskcache/file_cache_test.go

@@ -0,0 +1,55 @@
+package diskcache
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFileCache(t *testing.T) {
+	ctx := context.Background()
+	const (
+		key            = "key"
+		value          = "some text"
+		newValue       = "new text"
+		cacheRoot      = "/cache"
+		cachedFilePath = "a/62/a62f2225bf70bfaccbc7f1ef2a397836717377de"
+	)
+
+	fs := afero.NewMemMapFs()
+	cache := New(fs, "/cache")
+
+	// store new key
+	err := cache.Store(ctx, key, []byte(value))
+	require.NoError(t, err)
+	checkValue(t, ctx, fs, filepath.Join(cacheRoot, cachedFilePath), cache, key, value)
+
+	// update existing key
+	err = cache.Store(ctx, key, []byte(newValue))
+	require.NoError(t, err)
+	checkValue(t, ctx, fs, filepath.Join(cacheRoot, cachedFilePath), cache, key, newValue)
+
+	// delete key
+	err = cache.Delete(ctx, key)
+	require.NoError(t, err)
+	exists, err := afero.Exists(fs, filepath.Join(cacheRoot, cachedFilePath))
+	require.NoError(t, err)
+	require.False(t, exists)
+}
+
+func checkValue(t *testing.T, ctx context.Context, fs afero.Fs, fileFullPath string, cache *FileCache, key, wantValue string) { //nolint:golint
+	t.Helper()
+	// check actual file content
+	b, err := afero.ReadFile(fs, fileFullPath)
+	require.NoError(t, err)
+	require.Equal(t, wantValue, string(b))
+
+	// check cache content
+	b, ok, err := cache.Load(ctx, key)
+	require.NoError(t, err)
+	require.True(t, ok)
+	require.Equal(t, wantValue, string(b))
+}

diskcache/noop_cache.go

@@ -0,0 +1,24 @@
+package diskcache
+
+import (
+	"context"
+)
+
+type NoOp struct {
+}
+
+func NewNoOp() *NoOp {
+	return &NoOp{}
+}
+
+func (n *NoOp) Store(ctx context.Context, key string, value []byte) error {
+	return nil
+}
+
+func (n *NoOp) Load(ctx context.Context, key string) (value []byte, exist bool, err error) {
+	return nil, false, nil
+}
+
+func (n *NoOp) Delete(ctx context.Context, key string) error {
+	return nil
+}

http/http.go

@@ -14,7 +14,7 @@ type modifyRequest struct {
 	Which []string `json:"which"` // Answer to: which fields?
 }
 
-func NewHandler(imgSvc ImgService, store *storage.Storage, server *settings.Server) (http.Handler, error) {
+func NewHandler(imgSvc ImgService, fileCache FileCache, store *storage.Storage, server *settings.Server) (http.Handler, error) {
 	server.Clean()
 
 	r := mux.NewRouter()
@@ -60,7 +60,7 @@ func NewHandler(imgSvc ImgService, store *storage.Storage, server *settings.Serv
 
 	api.PathPrefix("/raw").Handler(monkey(rawHandler, "/api/raw")).Methods("GET")
 	api.PathPrefix("/preview/{size}/{path:.*}").
-		Handler(monkey(previewHandler(imgSvc, server.EnableThumbnails, server.ResizePreview), "/api/preview")).Methods("GET")
+		Handler(monkey(previewHandler(imgSvc, fileCache, server.EnableThumbnails, server.ResizePreview), "/api/preview")).Methods("GET")
 	api.PathPrefix("/command").Handler(monkey(commandsHandler, "/api/command")).Methods("GET")
 	api.PathPrefix("/search").Handler(monkey(searchHandler, "/api/search")).Methods("GET")
 

http/preview.go

@@ -1,8 +1,8 @@
 package http
 
 import (
+	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -23,7 +23,12 @@ type ImgService interface {
 	Resize(ctx context.Context, in io.Reader, width, height int, out io.Writer, options ...img.Option) error
 }
 
-func previewHandler(imgSvc ImgService, enableThumbnails, resizePreview bool) handleFunc {
+type FileCache interface {
+	Store(ctx context.Context, key string, value []byte) error
+	Load(ctx context.Context, key string) ([]byte, bool, 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
@@ -49,14 +54,14 @@ func previewHandler(imgSvc ImgService, enableThumbnails, resizePreview bool) han
 
 		switch file.Type {
 		case "image":
-			return handleImagePreview(imgSvc, w, r, file, size, enableThumbnails, resizePreview)
+			return handleImagePreview(w, r, imgSvc, fileCache, file, size, enableThumbnails, resizePreview)
 		default:
 			return http.StatusNotImplemented, fmt.Errorf("can't create preview for %s type", file.Type)
 		}
 	})
 }
 
-func handleImagePreview(imgSvc ImgService, w http.ResponseWriter, r *http.Request,
+func handleImagePreview(w http.ResponseWriter, r *http.Request, imgSvc ImgService, fileCache FileCache,
 	file *files.FileInfo, size string, enableThumbnails, resizePreview bool) (int, error) {
 	format, err := imgSvc.FormatFromExtension(file.Extension)
 	if err != nil {
@@ -67,6 +72,16 @@ func handleImagePreview(imgSvc ImgService, w http.ResponseWriter, r *http.Reques
 		return errToStatus(err), err
 	}
 
+	cacheKey := file.Path + size
+	cachedFile, ok, err := fileCache.Load(r.Context(), cacheKey)
+	if err != nil {
+		return errToStatus(err), err
+	}
+	if ok {
+		_, _ = w.Write(cachedFile)
+		return 0, nil
+	}
+
 	fd, err := file.Fs.Open(file.Path)
 	if err != nil {
 		return errToStatus(err), err
@@ -95,12 +110,18 @@ func handleImagePreview(imgSvc ImgService, w http.ResponseWriter, r *http.Reques
 		return 0, nil
 	}
 
-	if err := imgSvc.Resize(r.Context(), fd, width, height, w, options...); err != nil {
+	buf := &bytes.Buffer{}
-		switch {
+	if err := imgSvc.Resize(context.Background(), fd, width, height, buf, options...); err != nil {
-		case errors.Is(err, context.DeadlineExceeded), errors.Is(err, context.Canceled):
-		default:
 		return 0, err
 	}
+
+	go func() {
+		if err := fileCache.Store(context.Background(), cacheKey, buf.Bytes()); err != nil {
+			fmt.Printf("failed to cache resized image: %v", err)
 		}
+	}()
+
+	_, _ = w.Write(buf.Bytes())
+
 	return 0, nil
 }