How to use HttpWebRequest to download file

Question

Trying to download file in code.

Current code:

 Dim uri As New UriBuilder uri.UserName = "xxx" uri.Password = "xxx" uri.Host = "xxx" uri.Path = "xxx.aspx?q=65" Dim request As HttpWebRequest = DirectCast(WebRequest.Create(uri.Uri), HttpWebRequest) request.AllowAutoRedirect = True request = DirectCast(WebRequest.Create(DownloadUrlIn), HttpWebRequest) request.Timeout = 10000 'request.AllowWriteStreamBuffering = True Dim response As HttpWebResponse = Nothing response = DirectCast(request.GetResponse(), HttpWebResponse) Dim s As Stream = response.GetResponseStream() 'Write to disk Dim fs As New FileStream("c:\xxx.pdf", FileMode.Create) Dim read As Byte() = New Byte(255) {} Dim count As Integer = s.Read(read, 0, read.Length) While count > 0 fs.Write(read, 0, count) count = s.Read(read, 0, read.Length) End While 'Close everything fs.Close() s.Close() response.Close()

Running this code and checking the response.ResponseUri indicates im being redirected back to the login page and not to the pdf file.

For some reason its not authorising access what could I be missing as Im sending the user name and password in the uri? Thanks for your help

Does the page actually allow authorization via the url? Or do you need to authorize via a web interface that sets a cookie? Im guessing the later, in which case you will need to perform 2 requests, 1 to login and store the cookie, the second to request the pdf (using the cookie) — Steve
– Steve, Commented Nov 24, 2012 at 8:30
The code gave me a good start to perform my downloading. Thanks mate — MiBol
– MiBol, Commented Feb 23, 2013 at 22:48

Waleed · Accepted Answer · 2011-07-21 14:56:59Z

4

You don't need all of that code to download a file from the net just use the WebClient class and its DownloadFile method

answered Jul 21, 2011 at 14:56

Waleed

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1 Comment

David Over a year ago

Have tried this but with same problem that its redirecting to the login page.

mikro · Accepted Answer · 2013-02-09 06:03:05Z

0

you should check and see if the site requires cookies (most do), i'd use a packet analyzer and run your code and see exactly what the server is returning. use fiddler or http analyzer to log packets

answered Feb 9, 2013 at 6:03

mikro

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1 Comment

scones Over a year ago

Chrome developer tools or firefox with firebug should be enough to determine the existance of cookies and the actual request and response headers. But there are more sophisticated methods of scripting detection on some web applications.

Nepaluz · Accepted Answer · 2017-02-14 19:31:44Z

With UWP, this has become a more pertinent question as UWP does not have a WebClient. The correct answer to this question is if you are being re-directed to the login page, then there must be an issue with your credentials OR the setting (or lack of) header for the HttpWebRequest.

According to Microsoft, the request for downloading is sent with the call to GetResponse() on the HttpWebRequest, therefore the downloaded file SHOULD be in the stream in the response (returned by the GetResponse() call mentioned above).

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