feat: ftp server support (#7634 close #1898)

* feat: ftp server support

* fix(ftp): incorrect mode for dirs in LIST returns

server/ftp/afero.go

@@ -0,0 +1,91 @@
+package ftp
+
+import (
+	"context"
+	"errors"
+	ftpserver "github.com/KirCute/ftpserverlib-pasvportmap"
+	"github.com/alist-org/alist/v3/internal/errs"
+	"github.com/spf13/afero"
+	"os"
+	"time"
+)
+
+type AferoAdapter struct {
+	ctx context.Context
+}
+
+func NewAferoAdapter(ctx context.Context) *AferoAdapter {
+	return &AferoAdapter{ctx: ctx}
+}
+
+func (a *AferoAdapter) Create(_ string) (afero.File, error) {
+	// See also GetHandle
+	return nil, errs.NotImplement
+}
+
+func (a *AferoAdapter) Mkdir(name string, _ os.FileMode) error {
+	return Mkdir(a.ctx, name)
+}
+
+func (a *AferoAdapter) MkdirAll(path string, perm os.FileMode) error {
+	return a.Mkdir(path, perm)
+}
+
+func (a *AferoAdapter) Open(_ string) (afero.File, error) {
+	// See also GetHandle and ReadDir
+	return nil, errs.NotImplement
+}
+
+func (a *AferoAdapter) OpenFile(_ string, _ int, _ os.FileMode) (afero.File, error) {
+	// See also GetHandle
+	return nil, errs.NotImplement
+}
+
+func (a *AferoAdapter) Remove(name string) error {
+	return Remove(a.ctx, name)
+}
+
+func (a *AferoAdapter) RemoveAll(path string) error {
+	return a.Remove(path)
+}
+
+func (a *AferoAdapter) Rename(oldName, newName string) error {
+	return Rename(a.ctx, oldName, newName)
+}
+
+func (a *AferoAdapter) Stat(name string) (os.FileInfo, error) {
+	return Stat(a.ctx, name)
+}
+
+func (a *AferoAdapter) Name() string {
+	return "AList FTP Endpoint"
+}
+
+func (a *AferoAdapter) Chmod(_ string, _ os.FileMode) error {
+	return errs.NotSupport
+}
+
+func (a *AferoAdapter) Chown(_ string, _, _ int) error {
+	return errs.NotSupport
+}
+
+func (a *AferoAdapter) Chtimes(_ string, _ time.Time, _ time.Time) error {
+	return errs.NotSupport
+}
+
+func (a *AferoAdapter) ReadDir(name string) ([]os.FileInfo, error) {
+	return List(a.ctx, name)
+}
+
+func (a *AferoAdapter) GetHandle(name string, flags int, offset int64) (ftpserver.FileTransfer, error) {
+	if offset != 0 {
+		return nil, errors.New("offset")
+	}
+	if (flags & os.O_APPEND) > 0 {
+		return nil, errors.New("append")
+	}
+	if (flags & os.O_WRONLY) > 0 {
+		return OpenUpload(a.ctx, name)
+	}
+	return OpenDownload(a.ctx, name)
+}