Limit WebClient DownloadFile Maximum File Size

Question

In my asp.net project, my main page receives the URL as a parameter, which I need to load inside and then process it. I know that I can use the WebClient DownloadFile method, however I want the attacker to not give out the URL to a huge file, which will lead to unnecessary traffic from my server. To avoid this, I'm looking for a solution to set the maximum file size that DownloadFile will upload.

Thanks in advance,

Jack

Answer 1

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:

<system.web>
    <httpRuntime maxRequestLength="1024"/>

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// This will get the file
WebClient webClient = new WebClient();
webClient.DownloadFileCompleted += new System.ComponentModel.AsyncCompletedEventHandler(DownloadCompleted);
webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(DownloadProgressChanged);
webClient.DownloadFileAsync(new Uri("http://www.somewhere.com/test.txt"), @"c:\test.txt");

private void DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
{
    WebClient webClient = (WebClient)(sender);
    // Cancel download if we are going to download more than we allow
    if (e.TotalBytesToReceive > iMaxNumberOfBytesToAllow)
    {
        webClient.CancelAsync();
    }
}

private void DownloadCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)
{
    // Do something
}

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HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(new Uri("http://www.somewhere.com/test.txt"));
webRequest.Credentials = CredentialCache.DefaultCredentials;
HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse();
Int64 fileSize = webResponse.ContentLength;
if (fileSize < iMaxNumberOfBytesToAllow)
{
    // Download the file
}

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Answer 2

var webClient = new WebClient();
client.OpenRead(url);
Int64 bytesTotal = Convert.ToInt64(client.ResponseHeaders["Content-Length"]);

, bytesTotal