HTTP Protocol Downloading.

[jejacks0n]

Ok, here's the situation..

I want to download multiple files using the http protocol.

I know how to download a webpage and save it to a file using the inet.openURL/byteArray method, I know how to ftp files using the inet.execute "get/put" commands, and I know how to do a dialog free download.

But I'm unsatisfied using any of these methods to download an actual file (something larger then 10k) using http. Perhaps there is an easy answer that I've just overlooked, but...

Anyway, here are the methods that I've tried. This is a nice tutorial even if I don't get an answer. =).

Dialog Free Download method:
This is nice, it's fast and useful for small files, but it disables the form while the file is being transfered. This means if it's downloading a large file it will halt the form altogether until it's completed that download. Not very useful for what I need.

This is the code and usage, if there's any way to fix this please post.

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

For i = 0 to totaldownload
  DownloadFile ("http://foobar.file" & i, "c:\bleah.file")
Next i

Public Function DownloadFile(URL As String, LocalFilename As _
  String) As Boolean
    Dim lngRetVal As Long
    lngRetVal = URLDownloadToFile(0, URL, LocalFilename, 0, 0)
    If lngRetVal = 0 Then DownloadFile = True
End Function

Inet.OpenURL method:
This works nicely, you can add a progress bar and trap any errors, but writing to the file takes almost as long as the download time. If you remove the "DoEvents" from the For/Next statement it's a bit faster but still takes a long time. This is very usefull if you are downloading a web page document or something small, but not for larger files.

Code and usage. Any suggestions?

Dim byte As String
Dim b() As Byte
Dim o As Long

For i = 0 to totaldownload
  b() = Inet.OpenURL("http://foobar.file" & i, icByteArray)

  Open "c:\bleah.file" For Output As #1
    For o = 0 To UBound(b) - 1
      DoEvents
      byte = byte + Chr(b(o))
    Next o
    Print #1, byte
  Close #1
Next i

[FirePoweR]

This is what I use to download off of the internet:
Make sure you have a label on the form called "lblStats" if you want a percentage done.

Option Explicit
Public DlFile As String

Private Sub Inet1_StateChanged(ByVal State As Integer)
    Dim bDone As Boolean: bDone = False
    Dim Dat() As Byte, ff As Long
    Dim FileSize As Double
    
    Select Case State
        Case icResponseCompleted ' 12
            DoEvents
            Dat() = Inet1.GetChunk(1024, icByteArray)
            
            If UBound(Dat) <= 0 Then
                bDone = True
            End If
            
            FileSize = Val(Inet1.GetHeader("Content-Length:"))
            
            fs = FreeFile
            'Make DlFile a public variable and put the file name in it
            Open DlFile For Binary Access Write As #ff
            
            Put #ff, , Dat()
            
            Do While Not bDone
                Dat() = Inet1.GetChunk(1024, icByteArray)
                
                Put #ff, , Dat()
                
                'make a label for the status
                If FileSize > 0 Then lblStats = Int((FileSize / LOF(1)) * 100) & "%"
                
                If UBound(Dat) <= 0 Then
                    'If so, set the flag to indicate that we are done
                    bDone = True
                End If
            Loop
            Close #ff
    End Select
End Sub

Public Function CheckPath(FilePath As String) As Boolean
    FilePath = UCase(Trim(FilePath))
    On Error GoTo ErrH
    If (GetAttr(FilePath) And vbDirectory) <> 0 Then
        CheckPath = True
        Exit Function
    End If
    If Dir(FilePath) <> "" Then
        CheckPath = True
    Else
        CheckPath = False
    End If
    Exit Function
ErrH:
    CheckPath = False
End Function

Public Sub DownloadFile(URL As String, LocalFilename As String)
    Dim Headerz As String
    
    Headerz = "Referer: " & URL & vbCrLf & "User-Agent: PowerWeb (compatible; MSIE 4.01; Windows 98)" & vbCrLf & vbCrLf
    DlFile = LocalFilename
    If CheckPath(DlFile) Then Kill DlFile
    Inet1.Execute URL, "GET", , vbCrLf & vbCrLf & Headerz
    Do Until Inet1.StillExecuting = False
        DoEvents
    Loop
End Sub

If you want to be able to still use the form while its downloading then take out this in the DownloadFile function:

    Do Until Inet1.StillExecuting = False
        DoEvents
    Loop

Hope that helps...