feat(deflate): Non working deflate transfer mode

client_handler.go

@@ -2,6 +2,7 @@ package ftpserver
 
 import (
 	"bufio"
+	"compress/flate"
 	"errors"
 	"fmt"
 	"io"
@@ -34,6 +35,14 @@ const (
 	TransferTypeBinary
 )
 
+// TransferMode is the enumerable that represents the transfer mode (stream, block, compressed, deflate)
+type TransferMode int8
+
+const (
+	TransferModeStream  TransferMode = iota // TransferModeStream is the standard mode
+	TransferModeDeflate                     // TransferModeDeflate is the deflate mode
+)
+
 // DataChannel is the enumerable that represents the data channel (active or passive)
 type DataChannel int8
 
@@ -99,6 +108,7 @@ type clientHandler struct {
 	selectedHashAlgo    HASHAlgo        // algorithm used when we receive the HASH command
 	logger              log.Logger      // Client handler logging
 	currentTransferType TransferType    // current transfer type
+	transferMode        TransferMode    // Transfer mode (stream, block, compressed)
 	transferWg          sync.WaitGroup  // wait group for command that open a transfer connection
 	transferMu          sync.Mutex      // this mutex will protect the transfer parameters
 	transfer            transferHandler // Transfer connection (passive or active)s
@@ -663,6 +673,15 @@ func (c *clientHandler) TransferOpen(info string) (net.Conn, error) {
 		return nil, err
 	}
 
+	if c.transferMode == TransferModeDeflate {
+		conn, err = newDeflateConn(conn, c.server.settings.DeflateCompressionLevel)
+		if err != nil {
+			c.writeMessage(StatusActionNotTaken, fmt.Sprintf("Could not switch to deflate mode: %v", err))
+
+			return nil, fmt.Errorf("could not switch to deflate mode: %w", err)
+		}
+	}
+
 	c.isTransferOpen = true
 	c.transfer.SetInfo(info)
 
@@ -788,3 +807,38 @@ func getMessageLines(message string) []string {
 
 	return lines
 }
+
+type deflateConn struct {
+	net.Conn
+	io.Reader
+	*flate.Writer
+}
+
+func (c *deflateConn) Read(p []byte) (int, error) {
+	return c.Reader.Read(p)
+}
+
+func (c *deflateConn) Write(p []byte) (int, error) {
+	return c.Writer.Write(p)
+}
+
+func (c *deflateConn) Close() error {
+	errWriter := c.Writer.Flush()
+
+	if errWriter != nil {
+		return errWriter
+	}
+
+	return c.Conn.Close()
+}
+
+func newDeflateConn(conn net.Conn, compressionLevel int) (net.Conn, error) {
+	reader := flate.NewReader(conn)
+	writer, err := flate.NewWriter(conn, compressionLevel)
+
+	if err != nil {
+		return nil, fmt.Errorf("could not create deflate writer: %w", err)
+	}
+
+	return &deflateConn{Conn: conn, Reader: reader, Writer: writer}, nil
+}

driver.go

@@ -265,6 +265,7 @@ type Settings struct {
 	DisableSTAT              bool             // Disable Server STATUS, STAT on files and directories will still work
 	DisableSYST              bool             // Disable SYST
 	EnableCOMB               bool             // Enable COMB support
+	DeflateCompressionLevel  int              // Deflate compression level (1-9)
 	DefaultTransferType      TransferType     // Transfer type to use if the client don't send the TYPE command
 	// ActiveConnectionsCheck defines the security requirements for active connections
 	ActiveConnectionsCheck DataConnectionRequirement

handle_misc.go

@@ -284,9 +284,14 @@ func (c *clientHandler) handleTYPE(param string) error {
 }
 
 func (c *clientHandler) handleMODE(param string) error {
-	if param == "S" {
+	switch param {
+	case "S":
+		c.transferMode = TransferModeStream
 		c.writeMessage(StatusOK, "Using stream mode")
-	} else {
+	case "Z":
+		c.transferMode = TransferModeDeflate
+		c.writeMessage(StatusOK, "Using deflate mode")
+	default:
 		c.writeMessage(StatusNotImplementedParam, "Unsupported mode")
 	}
 

server.go

@@ -137,6 +137,10 @@ func (server *FtpServer) loadSettings() error {
 		settings.Banner = "ftpserver - golang FTP server"
 	}
 
+	if settings.DeflateCompressionLevel == 0 {
+		settings.DeflateCompressionLevel = 5
+	}
+
 	server.settings = settings
 
 	return nil

transfer_active.go

@@ -72,6 +72,9 @@ func (c *clientHandler) handlePORT(param string) error {
 	return nil
 }
 
+// activeTransferHandler implements the transferHandler interface
+var _ transferHandler = (*activeTransferHandler)(nil)
+
 // Active connection
 type activeTransferHandler struct {
 	raddr     *net.TCPAddr // Remote address of the client

transfer_pasv.go

@@ -26,6 +26,9 @@ type transferHandler interface {
 	GetInfo() string
 }
 
+// activeTransferHandler implements the transferHandler interface
+var _ transferHandler = (*passiveTransferHandler)(nil)
+
 // Passive connection
 type passiveTransferHandler struct {
 	listener    net.Listener     // TCP or SSL Listener

transfer_test.go

@@ -114,12 +114,20 @@ func ftpDownloadAndHash(t *testing.T, ftp *goftp.Client, filename string) string
 	return hex.EncodeToString(hasher.Sum(nil))
 }
 
-func ftpDownloadAndHashWithRawConnection(t *testing.T, raw goftp.RawConn, fileName string) string {
+type ftpDownloadOptions struct {
+	deflateMode bool
+}
+
+func ftpDownloadAndHashWithRawConnection(t *testing.T, raw goftp.RawConn, fileName string, options *ftpDownloadOptions) string {
 	t.Helper()
 
 	req := require.New(t)
 	hasher := sha256.New()
 
+	if options == nil {
+		options = &ftpDownloadOptions{}
+	}
+
 	dcGetter, err := raw.PrepareDataConn()
 	req.NoError(err)
 
@@ -130,6 +138,11 @@ func ftpDownloadAndHashWithRawConnection(t *testing.T, raw goftp.RawConn, fileNa
 	dataConn, err := dcGetter()
 	req.NoError(err)
 
+	if options.deflateMode {
+		dataConn, err = newDeflateConn(dataConn, 5)
+		req.NoError(err)
+	}
+
 	_, err = io.Copy(hasher, dataConn)
 	req.NoError(err)
 
@@ -143,15 +156,24 @@ func ftpDownloadAndHashWithRawConnection(t *testing.T, raw goftp.RawConn, fileNa
 	return hex.EncodeToString(hasher.Sum(nil))
 }
 
-func ftpUploadWithRawConnection(t *testing.T, raw goftp.RawConn, file io.Reader, fileName string, appendFile bool) {
+type ftpUploadOptions struct {
+	appendFile  bool
+	deflateMode bool
+}
+
+func ftpUploadWithRawConnection(t *testing.T, raw goftp.RawConn, file io.Reader, fileName string, options *ftpUploadOptions) {
 	t.Helper()
 
 	req := require.New(t)
 	dcGetter, err := raw.PrepareDataConn()
 	req.NoError(err)
 
+	if options == nil {
+		options = &ftpUploadOptions{}
+	}
+
 	cmd := "STOR"
-	if appendFile {
+	if options.appendFile {
 		cmd = "APPE"
 	}
 
@@ -162,6 +184,11 @@ func ftpUploadWithRawConnection(t *testing.T, raw goftp.RawConn, file io.Reader,
 	dataConn, err := dcGetter()
 	req.NoError(err)
 
+	if options.deflateMode {
+		dataConn, err = newDeflateConn(dataConn, 5)
+		req.NoError(err)
+	}
+
 	_, err = io.Copy(dataConn, file)
 	req.NoError(err)
 
@@ -536,7 +563,7 @@ func TestAPPEExistingFile(t *testing.T) {
 	_, err = file.Seek(1024, io.SeekStart)
 	require.NoError(t, err)
 
-	ftpUploadWithRawConnection(t, raw, file, fileName, true)
+	ftpUploadWithRawConnection(t, raw, file, fileName, &ftpUploadOptions{appendFile: true})
 
 	info, err := client.Stat(fileName)
 	require.NoError(t, err)
@@ -572,7 +599,7 @@ func TestAPPENewFile(t *testing.T) {
 
 	fileName := filepath.Base(file.Name())
 
-	ftpUploadWithRawConnection(t, raw, file, fileName, true)
+	ftpUploadWithRawConnection(t, raw, file, fileName, &ftpUploadOptions{appendFile: true})
 
 	localHash := hashFile(t, file)
 	remoteHash := ftpDownloadAndHash(t, client, fileName)
@@ -927,7 +954,7 @@ func TestASCIITransfers(t *testing.T) {
 	_, err = file.Seek(0, io.SeekStart)
 	require.NoError(t, err)
 
-	ftpUploadWithRawConnection(t, raw, file, "file.txt", false)
+	ftpUploadWithRawConnection(t, raw, file, "file.txt", nil)
 
 	files, err := client.ReadDir("/")
 	require.NoError(t, err)
@@ -939,7 +966,7 @@ func TestASCIITransfers(t *testing.T) {
 		require.Equal(t, int64(len(contents)), files[0].Size())
 	}
 
-	remoteHash := ftpDownloadAndHashWithRawConnection(t, raw, "file.txt")
+	remoteHash := ftpDownloadAndHashWithRawConnection(t, raw, "file.txt", nil)
 	localHash := hashFile(t, file)
 	require.Equal(t, localHash, remoteHash)
 }
@@ -979,9 +1006,9 @@ func TestASCIITransfersInvalidFiles(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, StatusOK, rc, response)
 
-	ftpUploadWithRawConnection(t, raw, file, "file.bin", false)
+	ftpUploadWithRawConnection(t, raw, file, "file.bin", nil)
 
-	remoteHash := ftpDownloadAndHashWithRawConnection(t, raw, "file.bin")
+	remoteHash := ftpDownloadAndHashWithRawConnection(t, raw, "file.bin", nil)
 	require.Equal(t, localHash, remoteHash)
 }
 
@@ -1231,3 +1258,46 @@ func getPortFromPASVResponse(t *testing.T, resp string) int {
 
 	return port
 }
+
+func TestTransferModeDeflate(t *testing.T) {
+	s := NewTestServer(t, false)
+	conf := goftp.Config{
+		User:     authUser,
+		Password: authPass,
+	}
+	client, err := goftp.DialConfig(conf, s.Addr())
+	require.NoError(t, err, "Couldn't connect")
+
+	defer func() { require.NoError(t, client.Close()) }()
+
+	raw, err := client.OpenRawConn()
+	require.NoError(t, err)
+
+	defer func() { require.NoError(t, raw.Close()) }()
+
+	file, err := os.CreateTemp("", "ftpserver")
+	require.NoError(t, err)
+
+	contents := []byte("line1\r\n\r\nline3\r\n,line4")
+	_, err = file.Write(contents)
+	require.NoError(t, err)
+
+	defer func() { require.NoError(t, file.Close()) }()
+
+	rc, response, err := raw.SendCommand("MODE Z")
+	require.NoError(t, err)
+	require.Equal(t, StatusOK, rc, response)
+
+	_, err = file.Seek(0, io.SeekStart)
+	require.NoError(t, err)
+
+	ftpUploadWithRawConnection(t, raw, file, "file.txt", &ftpUploadOptions{deflateMode: true})
+
+	files, err := client.ReadDir("/")
+	require.NoError(t, err)
+	require.Len(t, files, 1)
+
+	remoteHash := ftpDownloadAndHashWithRawConnection(t, raw, "file.txt", &ftpDownloadOptions{deflateMode: true})
+	localHash := hashFile(t, file)
+	require.Equal(t, localHash, remoteHash)
+}