B4X

ProgressMonSize Property

Demonstrates the case where the ProgressMonSize property is required to monitor the progress of FTP downloads.

When a file is downloaded, most FTP servers will indicate the file size in the intermediate "150" response. For example:

RETR hamlet.xml
150 Opening BINARY mode data connection for hamlet.xml (279658 Bytes).
226 Transfer complete.

However, some FTP servers do not provide the file size. For example, from a FileZilla server:

RETR files.txt
150 Connection accepted
226 Transfer OK

If the file size is not present, the component does not know how many bytes are forthcoming, and therefore it is not possible to monitor percentage completion progress -- unless the application provides a little help by setting the ProgressMonSize property just prior to calling GetFile.

The application should set the ProgressMonSize to the size indicated by GetSizeByName as demonstrated in this example.

B4X

Sub ftp_PercentDone (percentDone As Int) As Boolean
    Log("Percent Done: " & percentDone)
    Return False   ' Return True to abort
End Sub

Sub ftp_ProgressInfo (name As String, value As String)
    Log(name & ": " & value)
End Sub

Sub ChilkatExample

    Dim success As Boolean = False

    '  This example requires the Chilkat API to have been previously unlocked.
    '  See Global Unlock Sample for sample code.





    Dim ftp As ChilkatFtp2
    ftp.Initialize("ftp")

    ftp.Hostname = "ftp.example.com"
    ftp.Username = "login"
    ftp.Password = "password"

    ftp.KeepSessionLog = True

    '  Connect and login to the FTP server.
    success = ftp.Connect
    If success <> True Then
        Log(ftp.LastErrorText)
        Return
    End If


    '  Change to the remote directory where the file is located.
    '  This step is only necessary if the file is not in the root directory
    '  for the FTP account.
    success = ftp.ChangeRemoteDir("junk")
    If success <> True Then
        Log(ftp.LastErrorText)
        Return
    End If


    '  Download a file.
    Dim localFilename As String = "hamlet.xml"
    Dim remoteFilename As String = "hamlet.xml"

    '  If the FTP server does not supply the file size in the "150"
    '  intermediate response (to the RETR command), then tell
    '  the component how many bytes are forthcoming (if your
    '  application wishes to monitor the progress as a percentage
    '  completion).
    Dim fileSize As Int = ftp.GetSizeByName(remoteFilename)
    ftp.ProgressMonSize = fileSize

    success = ftp.GetFile(remoteFilename, localFilename)
    If success <> True Then
        Log(ftp.LastErrorText)
        Return
    End If

    Log(ftp.SessionLog)

    ftp.Disconnect

End Sub