Scenario: You want to know if a client completes a large download successfully.
Possible Solution: Create a custom ActionResult (perhaps derived from FileStreamResult) that streams the data and checks to see if the client remains connected.
public class CheckedFileStreamResult : FileStreamResult
{
public CheckedFileStreamResult(FileStream stream, string contentType)
:base(stream, contentType)
{
DownloadCompleted = false;
}
public bool DownloadCompleted { get; set; }
protected override void WriteFile(HttpResponseBase response)
{
var outputStream = response.OutputStream;
using (FileStream)
{
var buffer = new byte[_bufferSize];
var count = FileStream.Read(buffer, 0, _bufferSize);
while(count != 0 && response.IsClientConnected)
{
outputStream.Write(buffer, 0, count);
count = FileStream.Read(buffer, 0, _bufferSize);
}
DownloadCompleted = response.IsClientConnected;
}
}
private const int _bufferSize = 0x1000;
}
You can now log or audit the DownloadCompleted property of the result from an action filter. I'm sure this isn't 100% foolproof, but it seems to work reasonably well. Note: The IsClientConnected property of the response only tells the truth when running under IIS. With the WebDev server the property always returns true.