Adding an attribute to prevent type from being added

[anli-xsigns]

Product

Hot Chocolate

Is your feature request related to a problem?

Please see the source code at https://github.com/anli-xsigns/hc-graphql.

• In https://github.com/anli-xsigns/hc-graphql/blob/master/GraphQL/Program.cs I use .AddTypes() to add all types to the graphql server.
• Because Amenity https://github.com/anli-xsigns/hc-graphql/blob/master/Domain/Amenity.cs inherits from Entity https://github.com/anli-xsigns/hc-graphql/blob/master/Domain/Entity.cs and that has an IReadOnlyList<IDomainEvent> GetDomainEvents() HotChocolate tries to add the type IDomainEvent https://github.com/anli-xsigns/hc-graphql/blob/master/Domain/IDomainEvent.cs to the schema.
• That fails because of

HotChocolate.SchemaException: For more details look at the `Errors` property.

1. Interface `IDomainEvent` has no fields declared. (HotChocolate.Types.InterfaceType<Domain.IDomainEvent>)

   at HotChocolate.Configuration.TypeInitializer.EnsureNoErrors()
   at HotChocolate.Configuration.TypeInitializer.CompleteTypes()
   at HotChocolate.Configuration.TypeInitializer.Initialize()
   at HotChocolate.SchemaBuilder.Setup.InitializeTypes(SchemaBuilder builder, IDescriptorContext context, IReadOnlyList`1 types)
   at HotChocolate.SchemaBuilder.Setup.Create(SchemaBuilder builder, LazySchema lazySchema, IDescriptorContext context)
   at HotChocolate.SchemaBuilder.Create(IDescriptorContext context)
   at HotChocolate.SchemaBuilder.HotChocolate.ISchemaBuilder.Create(IDescriptorContext context)
   at HotChocolate.Execution.RequestExecutorResolver.CreateSchemaAsync(ConfigurationContext context, RequestExecutorSetup setup, RequestExecutorOptions executorOptions, IServiceProvider schemaServices, TypeModuleChangeMonitor typeModuleChangeMonitor, CancellationToken cancellationToken)
   at HotChocolate.Execution.RequestExecutorResolver.CreateSchemaServicesAsync(ConfigurationContext context, RequestExecutorSetup setup, CancellationToken cancellationToken)
   at HotChocolate.Execution.RequestExecutorResolver.GetRequestExecutorNoLockAsync(String schemaName, CancellationToken cancellationToken)
   at HotChocolate.Execution.RequestExecutorResolver.GetRequestExecutorAsync(String schemaName, CancellationToken cancellationToken)
   at HotChocolate.Execution.RequestExecutorProxy.GetRequestExecutorAsync(CancellationToken cancellationToken)
   at HotChocolate.AspNetCore.HttpPostMiddlewareBase.HandleRequestAsync(HttpContext context)
   at HotChocolate.AspNetCore.HttpPostMiddlewareBase.InvokeAsync(HttpContext context)
   at Microsoft.AspNetCore.Builder.EndpointRouteBuilderExtensions.<>c__DisplayClass20_0.<<UseCancellation>b__1>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

The solution you'd like

I would like to prevent HotChocolate from adding the IDomainEvent and even GetDomainEvents() to the schema with an attribute, e. g. [GraphQLIgnore]

[michaelstaib]

In general if doing DDD the entity types should not be exposed to the GraphQL type system. What we tend to do is throwing CQRS in and have a dedicated query layer that has access to an optimized read model. Only commands have access to the domain entities itself.

But you can also solve you problem ... if you inherit from the DefaultTypeInspector and override the IsMemberIgnored method you can check if your ignore condition is met and otherwise refer to the base.

public override bool IsMemberIgnored(MemberInfo member)
{
    if (member is null)
    {
        throw new ArgumentNullException(nameof(member));
    }

    if(member.Name == "GetDomainEvents")
    {
        return true;
    }

    return base.IsMemberIgnored(member);
}

Register you custom instance of the convention like this:

services.AddGraphQLServer().TryAddConvention<ITypeInspector, MyTypeInspector>();

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