Swashbuckle.webapi: Ignore CancellationToken parameters by default

[brettveenstra]

I can't find a way to flag a parameter on my method to exclude the CancellationToken parameter from generating in the documentation.

I propose a convention of ignoring this type of parameter during generation.

[rwwilden]

I agree that CancellationToken parameters should be ignored by default. In the meantime, here's a simple IOperationFilter that does just that:

public class SwaggerRemoveCancellationTokenParameterFilter : IOperationFilter
{
  public void Apply(Operation operation, SchemaRegistry schemaRegistry, ApiDescription apiDescription)
  {
    apiDescription.ParameterDescriptions
      .Where(pd => pd.ParameterDescriptor.ParameterType == typeof(CancellationToken))
      .ToList()
      .ForEach(pd =>
      {
        if (operation.parameters != null)
        {
          var cancellationTokenParameter = operation.parameters.Single(p => p.name == pd.Name);
          operation.parameters.Remove(cancellationTokenParameter);
        }
      });
  }
}

[dementeddevil]

Finally found out why my controller wasn't working and this was it - just spent all weekend trying to get this going.

If you are using swashbuckle v6 and ASP.NET 5 then the code you need differs slightly from the above sample.

The code below was what I had to use to get things going...

    public class SwaggerRemoveCancellationTokenParameterFilter : IOperationFilter
    {
        public void Apply(Operation operation, OperationFilterContext context)
        {
            context.ApiDescription.ParameterDescriptions
                .Where(pd =>
                    pd.ModelMetadata.ContainerType == typeof(CancellationToken) ||
                    pd.ModelMetadata.ContainerType == typeof(WaitHandle) ||
                    pd.ModelMetadata.ContainerType == typeof(SafeWaitHandle))
                .ToList()
                .ForEach(
                    pd =>
                    {
                        if (operation.Parameters != null)
                        {
                            var cancellationTokenParameter = operation.Parameters.Single(p => p.Name == pd.Name);
                            operation.Parameters.Remove(cancellationTokenParameter);
                        }
                    });
        }
    }

[TsengSR]

Definitely needs a fix for next version. @dementeddevil filter works perfectly though, but it took me hours to get it working

[Danielku15]

Even with removing the parameters, the models will end up in the schema. By generating a client via swagger-codegen you will end up with class definitions for CancellationToken , WaitHandle, SafeWaitHandle etc. Has anybody found out so far how to remove those schema entries again? ISchemaFilter only allows modifying of schemas, not excluding them.

[bhugot]

These implementation is not working you should use the document filter interface and remove those definitions from the schema registry

[domaindrivendev]

Fixed by 7ab9b842c5ad068dd7115a102bed45559133e0a6. Will automatically ignore parameters of type CancellationToken without the need for custom filters.