CODEWITHSUNDEEP
c#httpstreamhttprequestvisual-studio-2019
user7335295
user7335295

Reputation: 441

C# : Check wether HttpClient.GetStreamAsync(myURL) was successful?

I am using the GetStreamAsync-Method in order to read in a file through a stream. But I am wondering: What happens if the URL provided is currently not available? How would I know if GetStreamAsync failed?

Here is the code I am working with:

var tmpMyDataFile = Path.GetTempFileName();       
using (var myDataStream = await _httpClient.GetStreamAsync(MyURL))
{
    using (var tmpMyDataStream = File.OpenWrite(tmpMyDataFile))
    {
        await myDataStream.CopyToAsync(tmpMyDataStream);
    }
}

Do I have to do this through catching the HttpRequestException exception or is there some sort of StatusCode I could retrieve somehow? If I have to do this via exception catching, what exactly is the meaning of the TaskCanceledException described in the doc here: https://learn.microsoft.com/en-us/dotnet/api/system.net.http.httpclient.getstreamasync?view=net-5.0

TaskCanceledException: The request failed due to timeout. <- Which timeout?

Upvotes: 1

Views: 1050

Answers (1)

Stephen Cleary
Stephen Cleary

Reputation: 456417

What happens if the URL provided is currently not available? How would I know if GetStreamAsync failed?

As documented, you'll get an HttpRequestException. You can check the status code (if any) using its StatusCode property.

Do I have to do this through catching the HttpRequestException exception or is there some sort of StatusCode I could retrieve somehow?

If you want to avoid the exception, then you should use SendAsync, which returns an HttpResponseMessage with a StatusCode. Note that SendAsync will still throw an exception if it is unable to get any response at all.

If I have to do this via exception catching, what exactly is the meaning of the TaskCanceledException

Only on .NET Core and .NET 5+ only, TaskCanceledException indicates a timeout. By default, HttpClient.Timeout is set to 100 seconds. If you need to handle timeout exceptions, I recommend catching OperationCanceledException rather than TaskCanceledException.

Upvotes: 2

Related Questions