Add data channel (active/passive) information to the ClientContext in…

…terface (#248)

* GetLastDataChannel returns the last data channel mode (passive or active)

* use the paramsMutex for lastDataChannel updates

* update README.md with GetLastDataChannel update to ClientContext

* convert data channel to enums

README.md

@@ -114,6 +114,9 @@ type ClientContext interface {
 
 	// GetLastCommand returns the last received command
 	GetLastCommand() string
+
+	// GetLastDataChannel returns the last data channel mode
+	GetLastDataChannel() DataChannel
 }
 
 // Settings define all the server settings

client_handler.go

@@ -34,6 +34,15 @@ const (
 	TransferTypeBinary
 )
 
+// DataChannel is the enumerable that represents the data channel (active or passive)
+type DataChannel int
+
+// Supported data channel types
+const (
+	DataChannelPassive DataChannel = iota + 1
+	DataChannelActive
+)
+
 const (
 	maxCommandSize = 4096
 )
@@ -91,6 +100,7 @@ type clientHandler struct {
 	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
+	lastDataChannel     DataChannel     // Last data channel mode (passive or active)
 	isTransferOpen      bool            // indicate if the transfer connection is opened
 	isTransferAborted   bool            // indicate if the transfer was aborted
 	paramsMutex         sync.RWMutex    // mutex to protect the parameters exposed to the library users
@@ -231,13 +241,28 @@ func (c *clientHandler) GetLastCommand() string {
 	return c.command
 }
 
+// GetLastDataChannel returns the last data channel mode
+func (c *clientHandler) GetLastDataChannel() DataChannel {
+	c.paramsMutex.RLock()
+	defer c.paramsMutex.RUnlock()
+
+	return c.lastDataChannel
+}
+
 func (c *clientHandler) setLastCommand(cmd string) {
 	c.paramsMutex.Lock()
 	defer c.paramsMutex.Unlock()
 
 	c.command = cmd
 }
 
+func (c *clientHandler) setLastDataChannel(channel DataChannel) {
+	c.paramsMutex.Lock()
+	defer c.paramsMutex.Unlock()
+
+	c.lastDataChannel = channel
+}
+
 func (c *clientHandler) closeTransfer() error {
 	var err error
 	if c.transfer != nil {

client_handler_test.go

@@ -86,6 +86,11 @@ func TestLastCommand(t *testing.T) {
 	assert.Empty(t, cc.GetLastCommand())
 }
 
+func TestLastDataChannel(t *testing.T) {
+	cc := clientHandler{lastDataChannel: DataChannelPassive}
+	assert.Equal(t, DataChannelPassive, cc.GetLastDataChannel())
+}
+
 func TestTransferOpenError(t *testing.T) {
 	s := NewTestServer(t, true)
 	conf := goftp.Config{

driver.go

@@ -147,6 +147,9 @@ type ClientContext interface {
 
 	// GetLastCommand returns the last received command
 	GetLastCommand() string
+
+	// GetLastDataChannel returns the last data channel mode
+	GetLastDataChannel() DataChannel
 }
 
 // FileTransfer defines the inferface for file transfers.

transfer_active.go

@@ -55,6 +55,7 @@ func (c *clientHandler) handlePORT(param string) error {
 	}
 
 	c.transferMu.Unlock()
+	c.setLastDataChannel(DataChannelActive)
 
 	c.writeMessage(StatusOK, command+" command successful")
 

transfer_pasv.go

@@ -184,6 +184,7 @@ func (c *clientHandler) handlePASV(param string) error {
 	c.transferMu.Lock()
 	c.transfer = p
 	c.transferMu.Unlock()
+	c.setLastDataChannel(DataChannelPassive)
 
 	return nil
 }