[RESOLVED] VB6: Software freezes while downloading a file from web!

[IHappenToBe']

Hi.
I have a big software already running in many companies.
As a measure of security, I want to add to it a module that checks in a website (ftp with username & password) if I want the program to block it self, or send messages to user, or update it self, etc.

It download the file perfectly! The problem is it takes a little while to do it (like 3-5 seconds, and if it's offline, like a minute) and during it, the whole software freezes until it ends. I tried moving the routine to another form, but it's the same. I also thought of moving it to an independent exe that triggers when the main one runs, but nowadays Windows is so paranoic it would be very caotic (sandbox, firewall...) it has to do it quietly.

Any suggestions? I'm thinking of doing it when the program closes, or when it's inactive for 1 minute, but still, it's awkward and it just can't freeze like that, my clients are going to report it to me. TO SUM UP, I need it to do it quietly, silently, in background, no freezing (or at least that if it's offline, doesn't freeze for 1 minute).


The code I use is:

Option Explicit
Private Declare Function URLDownloadToFile Lib "urlmon" Alias "URLDownloadToFileA" (ByVal pCaller As Long, ByVal szURL As String, ByVal szFileName As String, ByVal dwReserved As Long, ByVal lpfnCB As Long) As Long
Private Declare Function InternetOpen Lib "wininet" Alias "InternetOpenA" (ByVal sAgent As String, ByVal lAccessType As Long, ByVal sProxyName As String, ByVal sProxyBypass As String, ByVal lFlags As Long) As Long
Private Declare Function InternetCloseHandle Lib "wininet" (ByVal hInet As Long) As Integer

Function InternetGetFile(sURLFileName As String, sSaveToFile As String, Optional bOverwriteExisting As Boolean = False) As Boolean
    Dim lRet As Long
    Const S_OK As Long = 0, E_OUTOFMEMORY = &H8007000E
    Const INTERNET_OPEN_TYPE_PRECONFIG = 0, INTERNET_FLAG_EXISTING_CONNECT = &H20000000
    Const INTERNET_OPEN_TYPE_DIRECT = 1, INTERNET_OPEN_TYPE_PROXY = 3
    Const INTERNET_FLAG_RELOAD = &H80000000
    
    On Error Resume Next
    'Create an internet connection
    lRet = InternetOpen("", INTERNET_OPEN_TYPE_DIRECT, vbNullString, vbNullString, 0)   '---> in this line it freezes and I can't do anything
    
    If bOverwriteExisting Then
        If Len(Dir$(sSaveToFile)) Then
            VBA.Kill sSaveToFile
        End If
    End If
    'Check file doesn't already exist
    If Len(Dir$(sSaveToFile)) = 0 Then
        'Download file
        lRet = URLDownloadToFile(0&, sURLFileName, sSaveToFile, 0&, 0)
        If Len(Dir$(sSaveToFile)) Then
            'File successfully downloaded
            InternetGetFile = True
        Else
            'Failed to download file
            If lRet = E_OUTOFMEMORY Then
                EscribeLog "Error serv: The buffer length is invalid or there was insufficient memory to complete the operation."
            Else
                EscribeLog "Error serv: (this is probably a proxy server error)." 'Escribelog is a function on my own, it's "WriteLog" in spanish
            End If
            InternetGetFile = False
        End If
    End If
    On Error GoTo 0
    
End Function

and I call it this way:

Public Sub RevWeb()
    On Error Resume Next
    Dim ppArch As String, pp As String, sn As String, accion As String, param As String, pplocal As String
    ppArch = App.Path + "\" + Format(Date + Time, "ddmmyyhhmmss")
    If InternetGetFile("adress/file.txt", ppArch, True) Then  '---> in this line it freezes!
        'it opens and processes the content of the file, now in hard disk
    End If
End Sub

THANK YOU VERY MUCH.
PS: English is not my native language, please excuse my grammar or spelling errors.

[westconn1]

if you can use a shell object for downloading it runs asyncronoulsy

also there is an example in code bank that uses an activex exe (.ocx) to do this

[IHappenToBe']

if you can use a shell object for downloading it runs asyncronoulsy

also there is an example in code bank that uses an activex exe (.ocx) to do this

First of all, thank you for your answer.
...I looked for it but I can't find that example, sorry.
Also I don't understand what you mean by "shell object".

[Bonnie West]

Are you sure the InternetOpen function is necessary? The URLDownloadToFile function was able to successfully download a small zip attachment from this forum all by itself. However, it did freeze the Form and the IDE while downloading. That's probably due to not passing parameters to pCaller and lpfnCB. If a callback and an IUnknown interface was provided, the UI might not have frozen.

[Bonnie West]

See Download files from the Web (No Winsock) for a UserControl approach to downloading files.

[westconn1]

have a look at http://www.vbforums.com/showthread.p...+file+download

[IHappenToBe']

have a look at http://www.vbforums.com/showthread.p...+file+download

Waw, problem SUPER-solved!
That was exactly what I needed. Thank you so much!