Downloading large files using XML HTTP Request - vbscript

Question

I'm trying to make a simple launcher for a game that can install and uninstall mods, and update them. I don't know a ton about VBScript, so I got most of the downloading/update code off of the internet. I have most of the code done, but I have a problem. I'm trying to download about a 1/2 GB large zip folder off of my google drive. It was working when all I had was a simple text file in the zip folder as a test, but all it did was download a corrupted zip folder. WinRar can't open it, giving the error message "The archive is in either unknown format or damaged". So my question is does the code that I'm using have a limit to the file size? I'm trying to download https://drive.google.com/uc?export=download&id=0BxlXlAM9nwYTZTFUdXpWQlJyN2M which is a direct download link to my google drive file.
Dim http: Set http = createobject("Microsoft.XMLHTTP")
Dim stream: Set stream = createobject("Adodb.Stream")
http.Open "GET", "https://drive.google.com/uc?export=download&id=0BxlXlAM9nwYTZTFUdXpWQlJyN2M", False
http.Send
With stream
.Type = 1
.Open
.Write http.responseBody
.SaveToFile "c:\updates\normaldata\normal.zip", 2
End With

Answer 1

As #Noodles already pointed out your original link is being redirected to a confirmation page, because the file is too large to be scanned for malware. You need to extract the actual download link from that page, e.g. like this:
baseUrl = "https://drive.google.com"
url = baseUrl & "/uc?export=download&id=0BxlXlAM9nwYTZTFUdXpWQlJyN2M"
Set http = CreateObject("Microsoft.XMLHTTP")
http.Open "GET", url, False
http.Send
If http.Status <> 200 Then
WScript.Echo http.Status & " " & http.StatusText
WScript.Quit 1
ElseIf Left(http.getResponseHeader("Content-Type"), 9) = "text/html" Then
Set html = CreateObject("HTMLFile")
html.Write http.ResponseText
Set dl = html.GetElementById("uc-download-link")
http.Open "GET", Replace(dl.href, "about:", baseUrl), False
http.Send
...
End If
However, when I tried to follow the link I got an access denied error, whereas the download worked fine in a browser. To make the VBScript work you may need to inspect the conversation between browser and the webserver (e.g. with Fiddler) and adjust the second HTTP request according to the results.

Answer 2

First that link is not a direct download. It takes you to a page that warns you the zip can't be virus scanned by Google.
What you aren't doing is
Opening the file in notepad and seeing what it says. Zips start with PK, Executables and dlls with MZ, and you'll recognise HTML. You are downloading a web page that is under 1000 bytes.
You have no error checking. Note my code is 80% error checking.
#define HTTP_STATUS_OK 200 // request completed
It gave you the page it wanted to give you.
This downloads a web page and saves it as a zip. Rename it html and open in internet explorer.
Set fso = CreateObject("Scripting.FileSystemObject")
Set Outp = Wscript.Stdout
Set wshShell = CreateObject("Wscript.Shell")
Set ShApp = CreateObject("Shell.Application")
On Error Resume Next
Set File = WScript.CreateObject("Msxml2.XMLHTTP.6.0")
File.Open "GET", "https://drive.google.com/uc?export=download&id=0BxlXlAM9nwYTZTFUdXpWQlJyN2M", False
File.setRequestHeader "User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 1.1.4322; .NET CLR 3.5.30729; .NET CLR 3.0.30618; .NET4.0C; .NET4.0E; BCD2000; BCD2000)"
File.Send
If err.number <> 0 then
wscript.echo ""
wscript.echo "Error getting file"
wscript.echo "=================="
wscript.echo ""
wscript.echo "Error " & err.number & "(0x" & hex(err.number) & ") " & err.description
wscript.echo "Source " & err.source
wscript.echo ""
wscript.echo "HTTP Error " & File.Status & " " & File.StatusText
wscript.echo File.getAllResponseHeaders
wscript.echo File.ResponseBody
else
On Error Goto 0
wscript.echo "Server Response " & File.Status & " " & File.StatusText
wscript.echo File.getAllResponseHeaders
wscript.echo File.ResponseBody
Set BS = CreateObject("ADODB.Stream")
BS.type = 1
BS.open
BS.Write File.ResponseBody
BS.SaveToFile ShApp.Namespace(&h10).self.path & "\file.zip", 2
End If