CancellationToken not workin on AppService with blazor project. #1632 | Support

drenton created 3 years ago

ABP Framework version: v4.3.3
UI type: Blazor
DB provider: EF Core
Tiered (MVC) or Identity Server Separated (Angular): no
Exception message and stack trace:
Steps to reproduce the issue:"

Hi there,

I'm trying to use CancellationToken for long running task, I cannot make it work in AppService. but it works well on my local api calls.

protected override async Task OnInitializedAsync()
{
    cts.CancelAfter(2000);//To test CancellationToken
    //Below cancellation work well. 
    //forecasts = await Http.GetFromJsonAsync<WeatherForecast[]>("https://localhost:44320/WeatherForecast/", cts.Token);
    
    //This does not work.
    var pageResult = await CallsAppService.GetListAsync(new GetCallsInput { }, cts.Token);
    Calls = pageResult.Items;
}

This is my GetListAsync from CallsAppService

public virtual async Task<PagedResultDto<CallDto>> GetListAsync(GetCallsInput input, CancellationToken ct = default)
{
    Thread.Sleep(3000);//On purpose to test CancellationToken
    var totalCount = await _callRepository.GetCountAsync(input.FilterText, input.Number, ct);
    var items = await _callRepository.GetListAsync(input.FilterText, input.Number, input.Sorting, input.MaxResultCount, input.SkipCount, ct);

    return new PagedResultDto<CallDto>
    {
        TotalCount = totalCount,
        Items = ObjectMapper.Map<List<Call>, List<CallDto>>(items)
    };
}

This is my CallController

[HttpGet]
public virtual Task<PagedResultDto<CallDto>> GetListAsync(GetCallsInput input, CancellationToken ct = default)
{
    return _callsAppService.GetListAsync(input, ct);
}

5 Answer(s)

0

liangshiwei created 3 years ago
Support Team Fullstack Developer

Hi,

Currently ABP does not support custom cancellationToken.

We have create an issue to enhance: https://github.com/abpframework/abp/issues/9668
0

drenton created 3 years ago

Hi @liangshiwei

I tried to use the provier too, but it does not work either. [It seems it just catches the same token, so I don't have to provide it in all the method]

Can you give me an example that show how to cancel a task from blazor razor view?

Thanks.
0

liangshiwei created 3 years ago
Support Team Fullstack Developer

Hi,

As I said, currently ABP does not support custom cancellationToken. because the request proxy interceptor always uses the ICancellationTokenProvider.

This PR will solve the issue, but 5.0.0 version, for now, you can implement it locally.

liangshiwei created 3 years ago

Support Team Fullstack Developer

HI,

This is a temporary solution:

public class CancellationTokenOverride
{
    public CancellationToken CancellationToken { get; }

    public CancellationTokenOverride(CancellationToken cancellationToken)
    {
        CancellationToken = cancellationToken;
    }
}


[Dependency(ReplaceServices = true)]
public class MyCancellationTokenProvider : ICancellationTokenProvider, ITransientDependency
{

    public const string CancellationTokenOverrideContextKey = "Volo.Abp.Threading.CancellationToken.Override";

    public CancellationToken Token { get
    {
        if (OverrideValue != null)
        {
            return OverrideValue.CancellationToken;
        }
        return _httpContextAccessor.HttpContext?.RequestAborted ?? CancellationToken.None;
    }}

    private readonly IAmbientScopeProvider<CancellationTokenOverride> _cancellationTokenOverrideScopeProvider;
    private readonly IHttpContextAccessor _httpContextAccessor;
    protected CancellationTokenOverride OverrideValue => _cancellationTokenOverrideScopeProvider.GetValue(CancellationTokenOverrideContextKey);

    public MyCancellationTokenProvider(
        IAmbientScopeProvider<CancellationTokenOverride> cancellationTokenOverrideScopeProvider,
        IHttpContextAccessor httpContextAccessor)
    {
        _cancellationTokenOverrideScopeProvider = cancellationTokenOverrideScopeProvider;
        _httpContextAccessor = httpContextAccessor;
    }

    public IDisposable Use(CancellationToken cancellationToken)
    {
        return _cancellationTokenOverrideScopeProvider.BeginScope(CancellationTokenOverrideContextKey, new CancellationTokenOverride(cancellationToken));
    }
}

protected override async Task OnInitializedAsync()
{
    cts.CancelAfter(2000);//To test CancellationToken
    
    using (((MyCancellationTokenProvider) _cancellationTokenProvider).Use(cts.Token))
    {
       var pageResult = await CallsAppService.GetListAsync(new GetCallsInput { });
       Calls = pageResult.Items;
    }
}

0

drenton created 3 years ago

Thanks @liangshiwei

That works wel ;)

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