Composition API - Parameter Validation

At the moment (in version 8.2/9.0/9.1), you have the option to throw ViExceptions instead of returning ValidationErrors from your validation code.

Thanks
Hanno

Hi Hanno,

The interface IRequestValidator is defined as:

  public interface IRequestValidator
  {
    string Name { get; }

    Task<IEnumerable<ValidationError>> ValidateAsync(IRequest request, CancellationToken ct = default (CancellationToken));
  }

 The extension methods on IMethod are defined as:

public static T WithValidator<T>(
      this T method,
      string name,
      Func<IRequest, ValidationError> validator)
      where T : IMethod
//--------------------------
    public static T WithValidator<T>(
      this T method,
      string name,
      Func<IRequest, CancellationToken, Task<ValidationError>> validator)
      where T : IMethod
//--------------------------
public static T WithValidator<T>(this T method, IRequestValidator validator) where T : IMethod
      
      

I tried to throw a ViException but I am getting a compilation error, it seems that nowhere we have an extension method that allows Task<ViException>. Can you help?

Hi Hanno,

The interface IRequestValidator is defined as:

  public interface IRequestValidator
  {
    string Name { get; }

    Task<IEnumerable<ValidationError>> ValidateAsync(IRequest request, CancellationToken ct = default (CancellationToken));
  }

 The extension methods on IMethod are defined as:

public static T WithValidator<T>(
      this T method,
      string name,
      Func<IRequest, ValidationError> validator)
      where T : IMethod
//--------------------------
    public static T WithValidator<T>(
      this T method,
      string name,
      Func<IRequest, CancellationToken, Task<ValidationError>> validator)
      where T : IMethod
//--------------------------
public static T WithValidator<T>(this T method, IRequestValidator validator) where T : IMethod
      
      

I tried to throw a ViException but I am getting a compilation error, it seems that nowhere we have an extension method that allows Task<ViException>. Can you help?

Hi,

Please post the code. It's hard to tell what the problem might be without knowing the code and the error.

            builder.AddMethod(Method.Define("roles/{roleId}/delete")
                            .WithDescription("Creates a request for the removal of the role. After approval the role will be deleted.")
                            .WithParameter(new RequestParameter()
                            {
                                Name = "roleId",
                                Type = typeof(string),
                                IsInQuery = false,
                                Description = "The id of the role"
                            })
                            .WithValidator("Check existence of role id", async (qr, ct) =>
                            {
                                var f = qr.Session.SqlFormatter();
                                var uidRole = qr.Parameters.Get<string>("roleId");
                                if (await qr.Session.Source().ExistsAsync("Org", f.AndRelation(
                                            f.UidComparison("UID_OrgRoot", "CCC-A1CC7114316443DD9CCACCD00C2FC459"),
                                            f.UidComparison("UID_Org", uidRole)), ct).ConfigureAwait(false))
                                {
                                    return null;
                                }
                                return new ValidationError("Role with id '{0}' can't be found", uidRole);
                            })
                            .Handle<Request>("DELETE", async (qr, ct) =>
                            {
                            // Not relevant
                            }));

The above compiles, when replacing the thrown ValidationError with a VIException it will not compile.

That is because you cannot return a ViException there; you need to throw it.

throw new ViException("Error message", ExceptionRelevance.EndUser);

Hi Hanno, 

I know that I can throw any exception here and not only VIException since we are not dealing with checked exceptions like we have in Java. In the end I am looking for maximum support from Intellisense since I am dealing with a for me unknown library. Maybe a feature request to broaden the types of exceptions that can be returned?

Thanks, 

Rodney 

Hi Rodney,

This feature request actually already exists (420303). Agree that this is an inconsistency in the model.

Thanks,

Hanno