Added support for MutationConventions

[FleloShe]

Added support for MutationConventions. Must use "[Error(typeof(ValidationException))]" on mutations with enabled conventions.

At the current time it is necessary to overwrite the DefaultValidationErrorsHandler to support errors apart from the "ValidationException" from FluentValidation

[Jonatthu]

@benmccallum any feedback on this?

[Jonatthu]

@FleloShe I do not think this is working, I am testing this locally

            if (context.ContextData.ContainsKey(WellKnownContextData.ValidatorDescriptorsParams))
            {
                throw new AggregateException(invalidResults.Select(x => new ValidationException(x.Result.Errors)));
            }

This line is not hitting

[FleloShe]

It absolutely does....

[FleloShe]

Maybe you did not enable MutationConventions for your endpoint?

Checkout https://chillicream.com/docs/hotchocolate/defining-a-schema/mutations/#errors for further reading.

Some hints

Use this on your endpoint:

        [Error(typeof(ValidationException))]
        [UseMutationConvention()]
        public async Task<YourModel?> YourMethod(...)
        {
           ...
        }

And this in your startup:

                .AddMutationConventions(
                    new MutationConventionOptions
                    {
                        //InputArgumentName = "input",
                        //InputTypeNamePattern = "{MutationName}Input",
                        PayloadTypeNamePattern = "{MutationName}Payload",
                        PayloadErrorTypeNamePattern = "{MutationName}Error",
                        PayloadErrorsFieldName = "errors",
                        ApplyToAllMutations = false
                    })

Also make sure you added a validator for your model.

[aradalvand]

If I'm not mistaken using Hot Chocolate's mutation conventions means you'll have your mutation input arguments directly as parameters on the corresponding mutation method, so I'm not sure how we could use FluentValidation in that case? What am I missing?

[TheWillard]

@FleloShe thanks for your work! I tried this branch myself and I couldn't get it to work. I pushed a small example (https://github.com/TheWillard/mutation-convention-fairybread-validation) where only the CreateAuthor3 Mutation Input gets validated. If you got time maybe you could take a look and tell me what I did wrong.