feat(local): support thumbnail cache (close #4216)

drivers/local/driver.go

@@ -1,7 +1,6 @@
 package local
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -20,7 +19,6 @@ import (
 	"github.com/alist-org/alist/v3/internal/sign"
 	"github.com/alist-org/alist/v3/pkg/utils"
 	"github.com/alist-org/alist/v3/server/common"
-	"github.com/disintegration/imaging"
 	_ "golang.org/x/image/webp"
 )
 
@@ -54,6 +52,12 @@ func (d *Local) Init(ctx context.Context) error {
 		}
 		d.Addition.RootFolderPath = abs
 	}
+	if d.ThumbCacheFolder != "" && !utils.Exists(d.ThumbCacheFolder) {
+		err := os.MkdirAll(d.ThumbCacheFolder, os.FileMode(d.mkdirPerm))
+		if err != nil {
+			return err
+		}
+	}
 	return nil
 }
 
@@ -135,36 +139,18 @@ func (d *Local) Link(ctx context.Context, file model.Obj, args model.LinkArgs) (
 	fullPath := file.GetPath()
 	var link model.Link
 	if args.Type == "thumb" && utils.Ext(file.GetName()) != "svg" {
-		var srcBuf *bytes.Buffer
-		if utils.GetFileType(file.GetName()) == conf.VIDEO {
-			videoBuf, err := GetSnapshot(fullPath, 10)
-			if err != nil {
-				return nil, err
-			}
-			srcBuf = videoBuf
-		} else {
-			imgData, err := os.ReadFile(fullPath)
-			if err != nil {
-				return nil, err
-			}
-			imgBuf := bytes.NewBuffer(imgData)
-			srcBuf = imgBuf
-		}
-
-		image, err := imaging.Decode(srcBuf)
+		buf, thumbPath, err := d.getThumb(file)
 		if err != nil {
 			return nil, err
 		}
-		thumbImg := imaging.Resize(image, 144, 0, imaging.Lanczos)
-		var buf bytes.Buffer
-		err = imaging.Encode(&buf, thumbImg, imaging.PNG)
-		if err != nil {
-			return nil, err
-		}
-		size := buf.Len()
-		link.Data = io.NopCloser(&buf)
 		link.Header = http.Header{
-			"Content-Length": []string{strconv.Itoa(size)},
+			"Content-Type": []string{"image/png"},
+		}
+		if thumbPath != nil {
+			link.FilePath = thumbPath
+		} else {
+			link.Data = io.NopCloser(buf)
+			link.Header.Set("Content-Length", strconv.Itoa(buf.Len()))
 		}
 	} else {
 		link.FilePath = &fullPath

drivers/local/meta.go

@@ -7,9 +7,10 @@ import (
 
 type Addition struct {
 	driver.RootPath
-	Thumbnail  bool   `json:"thumbnail" required:"true" help:"enable thumbnail"`
-	ShowHidden bool   `json:"show_hidden" default:"true" required:"false" help:"show hidden directories and files"`
-	MkdirPerm  string `json:"mkdir_perm" default:"777"`
+	Thumbnail        bool   `json:"thumbnail" required:"true" help:"enable thumbnail"`
+	ThumbCacheFolder string `json:"thumb_cache_folder"`
+	ShowHidden       bool   `json:"show_hidden" default:"true" required:"false" help:"show hidden directories and files"`
+	MkdirPerm        string `json:"mkdir_perm" default:"777"`
 }
 
 var config = driver.Config{

drivers/local/util.go

@@ -7,7 +7,12 @@ import (
 	"os"
 	"path/filepath"
 	"sort"
+	"strings"
 
+	"github.com/alist-org/alist/v3/internal/conf"
+	"github.com/alist-org/alist/v3/internal/model"
+	"github.com/alist-org/alist/v3/pkg/utils"
+	"github.com/disintegration/imaging"
 	ffmpeg "github.com/u2takey/ffmpeg-go"
 )
 
@@ -55,3 +60,52 @@ func readDir(dirname string) ([]fs.FileInfo, error) {
 	sort.Slice(list, func(i, j int) bool { return list[i].Name() < list[j].Name() })
 	return list, nil
 }
+
+func (d *Local) getThumb(file model.Obj) (*bytes.Buffer, *string, error) {
+	fullPath := file.GetPath()
+	thumbPrefix := "alist_thumb_"
+	thumbName := thumbPrefix + utils.GetMD5Encode(fullPath) + ".png"
+	if d.ThumbCacheFolder != "" {
+		// skip if the file is a thumbnail
+		if strings.HasPrefix(file.GetName(), thumbPrefix) {
+			return nil, &fullPath, nil
+		}
+		thumbPath := filepath.Join(d.ThumbCacheFolder, thumbName)
+		if utils.Exists(thumbPath) {
+			return nil, &thumbPath, nil
+		}
+	}
+	var srcBuf *bytes.Buffer
+	if utils.GetFileType(file.GetName()) == conf.VIDEO {
+		videoBuf, err := GetSnapshot(fullPath, 10)
+		if err != nil {
+			return nil, nil, err
+		}
+		srcBuf = videoBuf
+	} else {
+		imgData, err := os.ReadFile(fullPath)
+		if err != nil {
+			return nil, nil, err
+		}
+		imgBuf := bytes.NewBuffer(imgData)
+		srcBuf = imgBuf
+	}
+
+	image, err := imaging.Decode(srcBuf)
+	if err != nil {
+		return nil, nil, err
+	}
+	thumbImg := imaging.Resize(image, 144, 0, imaging.Lanczos)
+	var buf bytes.Buffer
+	err = imaging.Encode(&buf, thumbImg, imaging.PNG)
+	if err != nil {
+		return nil, nil, err
+	}
+	if d.ThumbCacheFolder != "" {
+		err = os.WriteFile(filepath.Join(d.ThumbCacheFolder, thumbName), buf.Bytes(), 0666)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+	return &buf, nil, nil
+}