How to add CancellationToken on Unity Web request?

Question

I wrote the following code that successfully downloads a photo from the link. But I want to set a cancellationToken for the request that can be activated by pressing the x key. please guide me.

private async void GetImage()
{
    var request = UnityWebRequest.Get(requestURI);

    await RequestEnd(request);
    
    // add cancellation when I press any key..

    var date = request.downloadHandler.data;
    
    texture2D = new Texture2D(1, 1);
    
    texture2D.LoadImage(date);
}

private static async Task RequestEnd(UnityWebRequest request)
{
    request.SendWebRequest();
    Debug.Log("Request Send");

    while (!request.isDone) await Task.Yield();
}

Answer 1

You need a variable of type CancellationTokenSource.

//inside the class
private CancellationTokenSource downloadCancellationTokenSource;
// inside GetImage.cs
this.downloadCancellationTokenSource = new CancellationTokenSource();
var token = this.downloadCancellationTokenSource.Token;
await RequestEnd(request, token);

And you add the token as a parameter to method RequestEnd():

private static async Task RequestEnd(UnityWebRequest request, CancellationToken token)
{
    request.SendWebRequest();
    Debug.Log("Request Send");

    while (!request.isDone) 
    {
       if (token.IsCancellationRequested)
       {
            Debug.Log("Task {0} cancelled");
            token.ThrowIfCancellationRequested();
       }
       await Task.Yield();
    }
}

Now, in an Update() method you can check for input "X" and cancel the async task:

private void Update()
{
  if(Input.GetKeyDown("X")
  {
        if (this.downloadCancellationTokenSource != null)
        {
            this.downloadCancellationTokenSource.Cancel();
            this.downloadCancellationTokenSource.Dispose();
            this.downloadCancellationTokenSource = null;
        }
  }
}