FtpWebRequest/FtpWebResponse :成功连接后，即使提供了错误的密码，也可以成功连接

Question

我正在使用用户提供的用户名/密码测试FTP连接。

如果我独立运行我的单元测试，一切都可以正常工作。但是如果我尝试一个有序的测试，在FTP_Test_Unsuccessful之前运行FTP_Test_Sucessful，FTP_Test_Unsuccessful测试失败:即使我在成功连接之后提供了错误的密码，FTP连接也是成功的。

Passed          Unit Test   FTP_Test_Unsuccessful       00:00:02.3566157
Passed          Unit Test   FTP_Test_Sucessful          00:00:00.3048244
Failed          Unit Test   FTP_Test_Unsuccessful       00:00:00.2696941
Not Executed    Unit Test   FTP_Test_Sucessful          00:00:00

我怎样才能“重置”FTP连接，这样FTP_Test_Unsuccessful才能正确地测试连接。

以下是我的单元测试：

'''<summary>
'''basic Unsuccessful FTP test
'''</summary>
<TestMethod()>
Public Sub FTP_Test_Unsuccessful()
    _TestSettings.FTPEnabled = True
    _TestSettings.ChangeFTPCredentials("User", "BadPasword")
    Try
        Assert.IsFalse(_TestSettings.TestFtpSettings())

    Catch ex As AssertFailedException
        Throw 

    Catch ex As Net.WebException
        Dim FTPResponse As FtpWebResponse = DirectCast(ex.Response, FtpWebResponse)
        Assert.AreEqual(FtpStatusCode.NotLoggedIn, FTPResponse.StatusCode)

    Catch ex As Exception
        Assert.Fail()
    End Try
End Sub

'''<summary>
'''basic Sucessful FTP test
'''</summary>
<TestMethod()>
Public Sub FTP_Test_Sucessful()
    _TestSettings.FTPEnabled = True
    _TestSettings.ChangeFTPCredentials("User", "GoodPasword")
    Assert.IsTrue(_TestSettings.TestFtpSettings())
End Sub

下面是相关的代码：

Public Function TestFtpSettings() As Boolean
    Dim FTPConnectionTestedSuccessfully As Boolean = False
    Dim response As FtpWebResponse = GetTestFtpResponse()
    Dim StatusCode As System.Net.FtpStatusCode = response.StatusCode
    response.Close()
    FTPConnectionTestedSuccessfully = (StatusCode = Net.FtpStatusCode.OpeningData)

    Return FTPConnectionTestedSuccessfully
End Function

Private Function GetTestFtpResponse() As FtpWebResponse
    Dim request As FtpWebRequest = GetFTPConnection(WebRequestMethods.Ftp.ListDirectory)
    Dim response As FtpWebResponse = GetFTPResponse(request)

    Return (response)
End Function

Private Function GetFTPConnection(Method As String) As FtpWebRequest
    'Get the object used to communicate with the server.

    Dim FTPAdress As Uri = New Uri(String.Format("ftp://{0}:{1}", _
                                                 Me.FTPServerName, _
                                                 Me.FTPPort))

    Dim request As FtpWebRequest = DirectCast(WebRequest.Create(FTPAdress),  _
                                              FtpWebRequest)

    request.Method = Method
    request.Credentials = New NetworkCredential(Me.FTPUserName,
                                                Me.GetDecryptedPassword)
    Return request
End Function

Public Function GetFTPResponse(request As FtpWebRequest) As FtpWebResponse
    Return DirectCast(request.GetResponse(), FtpWebResponse)
End Function

Answer 1

多亏了How to Reuse FtpWebRequest Connection上的这个答案，我才刚刚将request.KeepAlive = False添加到我的GetFTPConnection函数中。所有的测试都通过了。

Private Function GetFTPConnection(Method As String) As FtpWebRequest
    'Get the object used to communicate with the server.

    Dim FTPAdress As Uri = New Uri(String.Format("ftp://{0}:{1}", _
                                                 Me.FTPServerName, _
                                                 Me.FTPPort))

    Dim request As FtpWebRequest = DirectCast(WebRequest.Create(FTPAdress),  _
                                              FtpWebRequest)

    request.Method = Method
    request.KeepAlive = False
    request.Credentials = New NetworkCredential(Me.FTPUserName,
                                                Me.GetDecryptedPassword)
    Return request
End Function