feat(s3): add placeholder toggle and fix empty-folder delete behavior

Author: okatu-loli

drivers/s3/driver.go

@@ -69,6 +69,9 @@ func (d *S3) GetAddition() driver.Additional {
 }
 
 func (d *S3) Init(ctx context.Context) error {
+	if !strings.Contains(d.Storage.Addition, `"use_placeholder"`) {
+		d.UsePlaceholder = true
+	}
 	if d.Region == "" {
 		d.Region = "alist"
 	}
@@ -151,16 +154,20 @@ func (d *S3) Link(ctx context.Context, file model.Obj, args model.LinkArgs) (*mo
 }
 
 func (d *S3) MakeDir(ctx context.Context, parentDir model.Obj, dirName string) error {
-	return d.Put(ctx, &model.Object{
-		Path: stdpath.Join(parentDir.GetPath(), dirName),
-	}, &stream.FileStream{
-		Obj: &model.Object{
-			Name:     getPlaceholderName(d.Placeholder),
-			Modified: time.Now(),
-		},
-		Reader:   io.NopCloser(bytes.NewReader([]byte{})),
-		Mimetype: "application/octet-stream",
-	}, func(float64) {})
+	dirPath := stdpath.Join(parentDir.GetPath(), dirName)
+	if d.UsePlaceholder {
+		return d.Put(ctx, &model.Object{
+			Path: dirPath,
+		}, &stream.FileStream{
+			Obj: &model.Object{
+				Name:     getPlaceholderName(d.Placeholder),
+				Modified: time.Now(),
+			},
+			Reader:   io.NopCloser(bytes.NewReader([]byte{})),
+			Mimetype: "application/octet-stream",
+		}, func(float64) {})
+	}
+	return d.createDirMarker(ctx, dirPath)
 }
 
 func (d *S3) Move(ctx context.Context, srcObj, dstDir model.Obj) error {
@@ -214,6 +221,26 @@ func (d *S3) Put(ctx context.Context, dstDir model.Obj, s model.FileStreamer, up
 	return err
 }
 
+func (d *S3) putEmptyObject(ctx context.Context, key string) error {
+	uploader := s3manager.NewUploader(d.Session)
+	contentType := "application/octet-stream"
+	input := &s3manager.UploadInput{
+		Bucket:      &d.Bucket,
+		Key:         &key,
+		Body:        driver.NewLimitedUploadStream(ctx, bytes.NewReader([]byte{})),
+		ContentType: &contentType,
+	}
+	if storageClass := d.resolveStorageClass(); storageClass != nil {
+		input.StorageClass = storageClass
+	}
+	_, err := uploader.UploadWithContext(ctx, input)
+	return err
+}
+
+func (d *S3) createDirMarker(ctx context.Context, dirPath string) error {
+	return d.putEmptyObject(ctx, getKey(dirPath, true))
+}
+
 var (
 	_ driver.Driver = (*S3)(nil)
 	_ driver.Other  = (*S3)(nil)

drivers/s3/meta.go

@@ -19,6 +19,7 @@ type Addition struct {
 	Placeholder              string `json:"placeholder"`
 	ForcePathStyle           bool   `json:"force_path_style"`
 	ListObjectVersion        string `json:"list_object_version" type:"select" options:"v1,v2" default:"v1"`
+	UsePlaceholder           bool   `json:"use_placeholder" default:"true" help:"Create hidden placeholder file (for example .alist) to keep empty folders."`
 	RemoveBucket             bool   `json:"remove_bucket" help:"Remove bucket name from path when using custom host."`
 	AddFilenameToDisposition bool   `json:"add_filename_to_disposition" help:"Add filename to Content-Disposition header."`
 	StorageClass             string `json:"storage_class" type:"select" options:",standard,standard_ia,onezone_ia,intelligent_tiering,glacier,glacier_ir,deep_archive,archive" help:"Storage class for new objects. AWS and Tencent COS support different subsets (COS uses ARCHIVE/DEEP_ARCHIVE)."`

drivers/s3/util.go

@@ -8,6 +8,7 @@ import (
 	"path"
 	"strings"
 
+	"github.com/alist-org/alist/v3/internal/errs"
 	"github.com/alist-org/alist/v3/internal/model"
 	"github.com/alist-org/alist/v3/internal/op"
 	"github.com/alist-org/alist/v3/pkg/utils"
@@ -105,6 +106,9 @@ func (d *S3) listV1(prefix string, args model.ListArgs) ([]model.Obj, error) {
 			files = append(files, &file)
 		}
 		for _, object := range listObjectsResult.Contents {
+			if strings.HasSuffix(*object.Key, "/") {
+				continue
+			}
 			name := path.Base(*object.Key)
 			if !args.S3ShowPlaceholder && (name == getPlaceholderName(d.Placeholder) || name == d.Placeholder) {
 				continue
@@ -210,10 +214,13 @@ func (d *S3) copyFile(ctx context.Context, src string, dst string) error {
 }
 
 func (d *S3) copyDir(ctx context.Context, src string, dst string) error {
-	objs, err := op.List(ctx, d, src, model.ListArgs{S3ShowPlaceholder: true})
+	objs, err := op.List(ctx, d, src, model.ListArgs{S3ShowPlaceholder: true, Refresh: true})
 	if err != nil {
 		return err
 	}
+	if len(objs) == 0 && !d.UsePlaceholder {
+		return d.createDirMarker(ctx, dst)
+	}
 	for _, obj := range objs {
 		cSrc := path.Join(src, obj.GetName())
 		cDst := path.Join(dst, obj.GetName())
@@ -230,8 +237,13 @@ func (d *S3) copyDir(ctx context.Context, src string, dst string) error {
 }
 
 func (d *S3) removeDir(ctx context.Context, src string) error {
-	objs, err := op.List(ctx, d, src, model.ListArgs{})
+	d.cleanupDirArtifacts(src)
+
+	objs, err := op.List(ctx, d, src, model.ListArgs{Refresh: true})
 	if err != nil {
+		if errs.IsObjectNotFound(err) {
+			return nil
+		}
 		return err
 	}
 	for _, obj := range objs {
@@ -245,9 +257,14 @@ func (d *S3) removeDir(ctx context.Context, src string) error {
 			return err
 		}
 	}
+	d.cleanupDirArtifacts(src)
+	return nil
+}
+
+func (d *S3) cleanupDirArtifacts(src string) {
 	_ = d.removeFile(path.Join(src, getPlaceholderName(d.Placeholder)))
 	_ = d.removeFile(path.Join(src, d.Placeholder))
-	return nil
+	_ = d.removeFile(getKey(src, true))
 }
 
 func (d *S3) removeFile(src string) error {