Cloud backends: add support for FTP REST command

So partial downloads are now supported as for local fs

ftpd/handler.go

@@ -241,7 +241,7 @@ func (c *Connection) ReadDir(name string) ([]os.FileInfo, error) {
 }
 
 // GetHandle implements ClientDriverExtentionFileTransfer
-func (c *Connection) GetHandle(name string, flags int) (ftpserver.FileTransfer, error) {
+func (c *Connection) GetHandle(name string, flags int, offset int64) (ftpserver.FileTransfer, error) {
 	c.UpdateLastActivity()
 
 	p, err := c.Fs.ResolvePath(name)
@@ -251,10 +251,10 @@ func (c *Connection) GetHandle(name string, flags int) (ftpserver.FileTransfer,
 	if flags&os.O_WRONLY != 0 {
 		return c.uploadFile(p, name, flags)
 	}
-	return c.downloadFile(p, name)
+	return c.downloadFile(p, name, offset)
 }
 
-func (c *Connection) downloadFile(fsPath, ftpPath string) (ftpserver.FileTransfer, error) {
+func (c *Connection) downloadFile(fsPath, ftpPath string, offset int64) (ftpserver.FileTransfer, error) {
 	if !c.User.HasPerm(dataprovider.PermDownload, path.Dir(ftpPath)) {
 		return nil, c.GetPermissionDeniedError()
 	}
@@ -264,7 +264,7 @@ func (c *Connection) downloadFile(fsPath, ftpPath string) (ftpserver.FileTransfe
 		return nil, c.GetPermissionDeniedError()
 	}
 
-	file, r, cancelFn, err := c.Fs.Open(fsPath)
+	file, r, cancelFn, err := c.Fs.Open(fsPath, offset)
 	if err != nil {
 		c.Log(logger.LevelWarn, "could not open file %#v for reading: %+v", fsPath, err)
 		return nil, c.GetFsError(err)
@@ -272,7 +272,7 @@ func (c *Connection) downloadFile(fsPath, ftpPath string) (ftpserver.FileTransfe
 
 	baseTransfer := common.NewBaseTransfer(file, c.BaseConnection, cancelFn, fsPath, ftpPath, common.TransferDownload,
 		0, 0, false)
-	t := newTransfer(baseTransfer, nil, r, 0)
+	t := newTransfer(baseTransfer, nil, r, 0, offset)
 
 	return t, nil
 }
@@ -330,7 +330,7 @@ func (c *Connection) handleFTPUploadToNewFile(resolvedPath, filePath, requestPat
 
 	baseTransfer := common.NewBaseTransfer(file, c.BaseConnection, cancelFn, resolvedPath, requestPath,
 		common.TransferUpload, 0, 0, true)
-	t := newTransfer(baseTransfer, w, nil, quotaResult.GetRemainingSize())
+	t := newTransfer(baseTransfer, w, nil, quotaResult.GetRemainingSize(), 0)
 
 	return t, nil
 }
@@ -395,7 +395,7 @@ func (c *Connection) handleFTPUploadToExistingFile(flags int, resolvedPath, file
 
 	baseTransfer := common.NewBaseTransfer(file, c.BaseConnection, cancelFn, resolvedPath, requestPath,
 		common.TransferUpload, minWriteOffset, initialSize, false)
-	t := newTransfer(baseTransfer, w, nil, maxWriteSize)
+	t := newTransfer(baseTransfer, w, nil, maxWriteSize, 0)
 
 	return t, nil
 }

ftpd/internal_test.go

@@ -292,7 +292,7 @@ func TestResolvePathErrors(t *testing.T) {
 	if assert.Error(t, err) {
 		assert.EqualError(t, err, common.ErrGenericFailure.Error())
 	}
-	_, err = connection.GetHandle("", 0)
+	_, err = connection.GetHandle("", 0, 0)
 	if assert.Error(t, err) {
 		assert.EqualError(t, err, common.ErrGenericFailure.Error())
 	}
@@ -400,9 +400,11 @@ func TestTransferErrors(t *testing.T) {
 	}
 	baseTransfer := common.NewBaseTransfer(file, connection.BaseConnection, nil, file.Name(), testfile, common.TransferDownload,
 		0, 0, false)
-	tr := newTransfer(baseTransfer, nil, nil, 0)
+	tr := newTransfer(baseTransfer, nil, nil, 0, 0)
 	err = tr.Close()
 	assert.NoError(t, err)
+	_, err = tr.Seek(10, 0)
+	assert.Error(t, err)
 	buf := make([]byte, 64)
 	_, err = tr.Read(buf)
 	assert.Error(t, err)
@@ -416,7 +418,10 @@ func TestTransferErrors(t *testing.T) {
 	assert.NoError(t, err)
 	baseTransfer = common.NewBaseTransfer(nil, connection.BaseConnection, nil, testfile, testfile,
 		common.TransferUpload, 0, 0, false)
-	tr = newTransfer(baseTransfer, nil, r, 0)
+	tr = newTransfer(baseTransfer, nil, r, 0, 10)
+	pos, err := tr.Seek(10, 0)
+	assert.NoError(t, err)
+	assert.Equal(t, pos, tr.expectedOffset)
 	err = tr.closeIO()
 	assert.NoError(t, err)
 
@@ -425,11 +430,7 @@ func TestTransferErrors(t *testing.T) {
 	pipeWriter := vfs.NewPipeWriter(w)
 	baseTransfer = common.NewBaseTransfer(nil, connection.BaseConnection, nil, testfile, testfile,
 		common.TransferUpload, 0, 0, false)
-	tr = newTransfer(baseTransfer, pipeWriter, nil, 0)
-	_, err = tr.Seek(1, 0)
-	if assert.Error(t, err) {
-		assert.EqualError(t, err, common.ErrOpUnsupported.Error())
-	}
+	tr = newTransfer(baseTransfer, pipeWriter, nil, 0, 0)
 
 	err = r.Close()
 	assert.NoError(t, err)
@@ -440,6 +441,10 @@ func TestTransferErrors(t *testing.T) {
 	}()
 	err = tr.closeIO()
 	assert.EqualError(t, err, errFake.Error())
+	_, err = tr.Seek(1, 0)
+	if assert.Error(t, err) {
+		assert.EqualError(t, err, common.ErrOpUnsupported.Error())
+	}
 	err = os.Remove(testfile)
 	assert.NoError(t, err)
 }

ftpd/server.go

@@ -15,22 +15,25 @@ import (
 	"github.com/drakkan/sftpgo/logger"
 	"github.com/drakkan/sftpgo/metrics"
 	"github.com/drakkan/sftpgo/utils"
+	"github.com/drakkan/sftpgo/version"
 )
 
 // Server implements the ftpserverlib MainDriver interface
 type Server struct {
-	config     *Configuration
-	certMgr    *common.CertManager
-	initialMsg string
+	config       *Configuration
+	certMgr      *common.CertManager
+	initialMsg   string
+	statusBanner string
 }
 
 // NewServer returns a new FTP server driver
 func NewServer(config *Configuration, configDir string) (*Server, error) {
 	var err error
 	server := &Server{
-		config:     config,
-		certMgr:    nil,
-		initialMsg: config.Banner,
+		config:       config,
+		certMgr:      nil,
+		initialMsg:   config.Banner,
+		statusBanner: fmt.Sprintf("SFTPGo %v FTP Server", version.Get().Version),
 	}
 	certificateFile := getConfigPath(config.CertificateFile, configDir)
 	certificateKeyFile := getConfigPath(config.CertificateKeyFile, configDir)
@@ -86,7 +89,8 @@ func (s *Server) GetSettings() (*ftpserver.Settings, error) {
 		PassiveTransferPortRange: portRange,
 		ActiveTransferPortNon20:  s.config.ActiveTransfersPortNon20,
 		IdleTimeout:              -1,
-		ConnectionTimeout:        30,
+		ConnectionTimeout:        20,
+		Banner:                   s.statusBanner,
 	}, nil
 }
 

ftpd/transfer.go

@@ -1,6 +1,7 @@
 package ftpd
 
 import (
+	"errors"
 	"io"
 	"sync/atomic"
 
@@ -14,14 +15,15 @@ import (
 // It implements the ftpserver.FileTransfer interface to handle files downloads and uploads
 type transfer struct {
 	*common.BaseTransfer
-	writer       io.WriteCloser
-	reader       io.ReadCloser
-	isFinished   bool
-	maxWriteSize int64
+	writer         io.WriteCloser
+	reader         io.ReadCloser
+	isFinished     bool
+	maxWriteSize   int64
+	expectedOffset int64
 }
 
 func newTransfer(baseTransfer *common.BaseTransfer, pipeWriter *vfs.PipeWriter, pipeReader *pipeat.PipeReaderAt,
-	maxWriteSize int64) *transfer {
+	maxWriteSize, expectedOffset int64) *transfer {
 	var writer io.WriteCloser
 	var reader io.ReadCloser
 	if baseTransfer.File != nil {
@@ -33,11 +35,12 @@ func newTransfer(baseTransfer *common.BaseTransfer, pipeWriter *vfs.PipeWriter,
 		reader = pipeReader
 	}
 	return &transfer{
-		BaseTransfer: baseTransfer,
-		writer:       writer,
-		reader:       reader,
-		isFinished:   false,
-		maxWriteSize: maxWriteSize,
+		BaseTransfer:   baseTransfer,
+		writer:         writer,
+		reader:         reader,
+		isFinished:     false,
+		maxWriteSize:   maxWriteSize,
+		expectedOffset: expectedOffset,
 	}
 }
 
@@ -81,8 +84,16 @@ func (t *transfer) Write(p []byte) (n int, err error) {
 // Seek sets the offset to resume an upload or a download
 func (t *transfer) Seek(offset int64, whence int) (int64, error) {
 	if t.File != nil {
-		return t.File.Seek(offset, whence)
+		ret, err := t.File.Seek(offset, whence)
+		if err != nil {
+			t.TransferError(err)
+		}
+		return ret, err
+	}
+	if t.reader != nil && t.expectedOffset == offset && whence == io.SeekStart {
+		return offset, nil
 	}
+	t.TransferError(errors.New("seek is unsupported for this transfer"))
 	return 0, common.ErrOpUnsupported
 }
 

go.mod

@@ -48,6 +48,6 @@ require (
 
 replace (
 	github.com/jlaffaye/ftp => github.com/drakkan/ftp v0.0.0-20200730125632-b21eac28818c
-	github.com/fclairamb/ftpserverlib => github.com/drakkan/ftpserverlib v0.0.0-20200731174440-5032a4cc72f5
+	github.com/fclairamb/ftpserverlib => github.com/drakkan/ftpserverlib v0.0.0-20200731183125-82c4b2b9bb35
 	golang.org/x/crypto => github.com/drakkan/crypto v0.0.0-20200731130417-7674a892f9b1
 )

go.sum

@@ -105,8 +105,8 @@ github.com/drakkan/crypto v0.0.0-20200731130417-7674a892f9b1 h1:EjZwDKOSCvUUXilY
 github.com/drakkan/crypto v0.0.0-20200731130417-7674a892f9b1/go.mod h1:v3bhWOXGYda7H5d2s5t9XA6th3fxW3s0MQxU1R96G/w=
 github.com/drakkan/ftp v0.0.0-20200730125632-b21eac28818c h1:QSXIWohSNn0negBVSKEjKTpdpGEsW7weVW8QNzviLHY=
 github.com/drakkan/ftp v0.0.0-20200730125632-b21eac28818c/go.mod h1:2lmrmq866uF2tnje75wQHzmPXhmSWUt7Gyx2vgK1RCU=
-github.com/drakkan/ftpserverlib v0.0.0-20200731174440-5032a4cc72f5 h1:BdTp34B+hh3MXvaf50ALb3Hx6QXHiprx01IC+u/VUnU=
-github.com/drakkan/ftpserverlib v0.0.0-20200731174440-5032a4cc72f5/go.mod h1:Jwd+zOP3T0kwiCQcgjpu3VWtc7AI6Nu4UPN2HYqaniM=
+github.com/drakkan/ftpserverlib v0.0.0-20200731183125-82c4b2b9bb35 h1:fS1f/T5ruUySzUD5m4VFhnEXjgPAUm/KwLZG+s/W83E=
+github.com/drakkan/ftpserverlib v0.0.0-20200731183125-82c4b2b9bb35/go.mod h1:Jwd+zOP3T0kwiCQcgjpu3VWtc7AI6Nu4UPN2HYqaniM=
 github.com/dustin/go-humanize v0.0.0-20171111073723-bb3d318650d4/go.mod h1:HtrtbFcZ19U5GC7JDqmcUSB87Iq5E25KnS6fMYU6eOk=
 github.com/eapache/go-resiliency v1.1.0/go.mod h1:kFI+JgMyC7bLPUVY133qvEBtVayf5mFgVsvEsIPBvNs=
 github.com/eapache/go-xerial-snappy v0.0.0-20180814174437-776d5712da21/go.mod h1:+020luEh2TKB4/GOp8oxxtq0Daoen/Cii55CzbTV6DU=

sftpd/handler.go

@@ -66,7 +66,7 @@ func (c *Connection) Fileread(request *sftp.Request) (io.ReaderAt, error) {
 		return nil, c.GetFsError(err)
 	}
 
-	file, r, cancelFn, err := c.Fs.Open(p)
+	file, r, cancelFn, err := c.Fs.Open(p, 0)
 	if err != nil {
 		c.Log(logger.LevelWarn, "could not open file %#v for reading: %+v", p, err)
 		return nil, c.GetFsError(err)

sftpd/scp.go

@@ -475,7 +475,7 @@ func (c *scpCommand) handleDownload(filePath string) error {
 		c.sendErrorMessage(common.ErrPermissionDenied)
 	}
 
-	file, r, cancelFn, err := c.connection.Fs.Open(p)
+	file, r, cancelFn, err := c.connection.Fs.Open(p, 0)
 	if err != nil {
 		c.connection.Log(logger.LevelError, "could not open file %#v for reading: %v", p, err)
 		c.sendErrorMessage(c.connection.GetFsError(err))

vfs/gcsfs.go

@@ -133,7 +133,7 @@ func (fs GCSFs) Lstat(name string) (os.FileInfo, error) {
 }
 
 // Open opens the named file for reading
-func (fs GCSFs) Open(name string) (*os.File, *pipeat.PipeReaderAt, func(), error) {
+func (fs GCSFs) Open(name string, offset int64) (*os.File, *pipeat.PipeReaderAt, func(), error) {
 	r, w, err := pipeat.AsyncWriterPipeInDir(fs.localTempDir)
 	if err != nil {
 		return nil, nil, nil, err
@@ -141,7 +141,11 @@ func (fs GCSFs) Open(name string) (*os.File, *pipeat.PipeReaderAt, func(), error
 	bkt := fs.svc.Bucket(fs.config.Bucket)
 	obj := bkt.Object(name)
 	ctx, cancelFn := context.WithCancel(context.Background())
-	objectReader, err := obj.NewReader(ctx)
+	objectReader, err := obj.NewRangeReader(ctx, offset, -1)
+	if err == nil && offset > 0 && objectReader.Attrs.ContentEncoding == "gzip" {
+		err = fmt.Errorf("Range request is not possible for gzip content encoding, requested offset %v", offset)
+		objectReader.Close()
+	}
 	if err != nil {
 		r.Close()
 		w.Close()

vfs/osfs.go

@@ -59,7 +59,7 @@ func (OsFs) Lstat(name string) (os.FileInfo, error) {
 }
 
 // Open opens the named file for reading
-func (OsFs) Open(name string) (*os.File, *pipeat.PipeReaderAt, func(), error) {
+func (OsFs) Open(name string, offset int64) (*os.File, *pipeat.PipeReaderAt, func(), error) {
 	f, err := os.Open(name)
 	return f, nil, nil, err
 }

vfs/s3fs.go

@@ -163,19 +163,24 @@ func (fs S3Fs) Lstat(name string) (os.FileInfo, error) {
 }
 
 // Open opens the named file for reading
-func (fs S3Fs) Open(name string) (*os.File, *pipeat.PipeReaderAt, func(), error) {
+func (fs S3Fs) Open(name string, offset int64) (*os.File, *pipeat.PipeReaderAt, func(), error) {
 	r, w, err := pipeat.AsyncWriterPipeInDir(fs.localTempDir)
 	if err != nil {
 		return nil, nil, nil, err
 	}
 	ctx, cancelFn := context.WithCancel(context.Background())
 	downloader := s3manager.NewDownloaderWithClient(fs.svc)
+	var streamRange *string
+	if offset > 0 {
+		streamRange = aws.String(fmt.Sprintf("bytes=%v-", offset))
+	}
+
 	go func() {
 		defer cancelFn()
-		key := name
 		n, err := downloader.DownloadWithContext(ctx, w, &s3.GetObjectInput{
 			Bucket: aws.String(fs.config.Bucket),
-			Key:    aws.String(key),
+			Key:    aws.String(name),
+			Range:  streamRange,
 		})
 		w.CloseWithError(err) //nolint:errcheck // the returned error is always null
 		fsLog(fs, logger.LevelDebug, "download completed, path: %#v size: %v, err: %v", name, n, err)

vfs/vfs.go

@@ -22,7 +22,7 @@ type Fs interface {
 	ConnectionID() string
 	Stat(name string) (os.FileInfo, error)
 	Lstat(name string) (os.FileInfo, error)
-	Open(name string) (*os.File, *pipeat.PipeReaderAt, func(), error)
+	Open(name string, offset int64) (*os.File, *pipeat.PipeReaderAt, func(), error)
 	Create(name string, flag int) (*os.File, *PipeWriter, func(), error)
 	Rename(source, target string) error
 	Remove(name string, isDir bool) error