check the TYPE parameter in a case-insensitive manner (#386)

* check the TYPE parameter in a case-insensitive manner
* add some tests

Author: drakkan

handle_misc.go

@@ -257,6 +257,7 @@ func (c *clientHandler) handleFEAT(param string) error {
 }
 
 func (c *clientHandler) handleTYPE(param string) error {
+	param = strings.ReplaceAll(strings.ToUpper(param), " ", "")
 	switch param {
 	case "I", "L8":
 		c.currentTransferType = TransferTypeBinary

handle_misc_test.go

@@ -297,6 +297,22 @@ func TestTYPE(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, StatusOK, rc)
 
+	rc, _, err = raw.SendCommand("TYPE i")
+	require.NoError(t, err)
+	require.Equal(t, StatusOK, rc)
+
+	rc, _, err = raw.SendCommand("TYPE a")
+	require.NoError(t, err)
+	require.Equal(t, StatusOK, rc)
+
+	rc, _, err = raw.SendCommand("TYPE l 8")
+	require.NoError(t, err)
+	require.Equal(t, StatusOK, rc)
+
+	rc, _, err = raw.SendCommand("TYPE l 7")
+	require.NoError(t, err)
+	require.Equal(t, StatusOK, rc)
+
 	rc, _, err = raw.SendCommand("TYPE wrong")
 	require.NoError(t, err)
 	require.Equal(t, StatusNotImplementedParam, rc)