C# HttpClient Abruptly stops download-CodePudding

I have this C# Script that is supposed to download a zip archive from GitHub, unpack it and put it in a specific folder:

using (var client = new HttpClient())
{
    var filePath = Path.GetFullPath("runtime");@"https://github.com/BlackBirdTV/tank/releases/latest/download/runtime.zip?raw=true";
    ConsoleUtilities.UpdateProgress("Downloading Runtime...", 0);
    var request = await client.GetStreamAsync(url);
    var buffer = new byte[(int)bufferSize];
    var totalBytesRead = 0;
    int bytes = 0;
    while ((bytes = await request.ReadAsync(buffer, 0, buffer.Length)) != 0)
    {
        totalBytesRead  = bytes;
        ConsoleUtilities.UpdateProgress($"Downloading Runtime... ({totalBytesRead} of {bufferSize} bytes read) ", (int)(totalBytesRead / bufferSize * 100));
    }
}
Decompress(buffer, filePath);

When I now run this, the download starts and it seems like it finishes, yet at a sporadic place it just stops. Somehow, It downloads the bytes as my Console shows, but they are zeroed out. It seems like either my computer receives zeros (which I doubt) or the bytes don't get written to the buffer.

Weirdly enough, downloading the file over the browser works just fine.

Any help is greatly appreciated

CodePudding user response：

As I state in the comments, your problem is that each iteration of your while loop is overwriting your buffer, and you are not accumulating the data anywhere. So your last iteration doesn't completely fill the buffer and all you're left with is whatever data you got in the last iteration.

You could fix that bug by storing the accumulated buffer somewhere, but a far better solution is to not fuss with buffers and such and just use the built-in CopyToAsync method of Stream:

using var client = new HttpClient();
using var stream = await client.GetStreamAsync("https://github.com/BlackBirdTV/tank/releases/latest/download/runtime.zip?raw=true");
using var file = new FileStream(@"c:\temp\runtime.zip", FileMode.Create);
await stream.CopyToAsync(file);

Here I'm saving it to a local file at c:\temp\runtime.zip, but obviously change that to suit your needs. I suppose you're avoiding this method so you can track progress, which is fair enough. So if that's really important to you, read on for a fix to your original solution.

For completeness, here's your original code fixed up to work by writing the buffer to a FileStream:

var bufferSize = 1024 * 10;
var url = @"https://github.com/BlackBirdTV/tank/releases/latest/download/runtime.zip?raw=true";

using var client = new HttpClient();
using var stream = await client.GetStreamAsync(url);
using var file = new FileStream(@"c:\temp\runtime.zip", FileMode.Create);

var filePath = Path.GetFullPath("runtime"); 
var request = await client.GetStreamAsync(url);
var buffer = new byte[(int)bufferSize];
var totalBytesRead = 0;
int bytes = 0;
while ((bytes = await request.ReadAsync(buffer, 0, buffer.Length)) != 0)
{
    await file.WriteAsync(buffer, 0, bytes);
    totalBytesRead  = bytes;
    ConsoleUtilities.UpdateProgress($"Downloading Runtime... ({totalBytesRead} of {bufferSize} bytes read) ", (int)(totalBytesRead / bufferSize * 100));
}