Directive Middleware

I need to validate fields before process query/mutation. For example, I need to check is email have correct format, and is password strong enough. Seems that is not possible for now, I can’t find any examples in documentation and source code.

I suggest to create generic method Validate in ArgumentDescriptor that accepts validation function. This function must return validation result. Validation result contains flag, that indicates validation success, and optionally contains error message, if validation was failed.

Here is an example of Validate function usage:

descriptor
    .Field(t => t.RegisterUser(default, default))
    .Type<NonNullType<UserType>>()
    .Argument("email", a => a
        .Type<NonNullType<StringType>>())
        .Validate<string>(x => ValidationUtility.IsValidEmail(x))
    .Argument("password", a => a
        .Type<NonNullType<StringType>>())
        .Validate<string>(x => ValidationUtility.IsPasswordStrong(x));

Also, I think this method can have more wide application, we can create it in FieldDescriptor and use for check user permissions on mutation or query.

[michaelstaib]

I will close this issue and create follow up issues for interface support and so on…

[michaelstaib]

Once we have implemented these for custom use you could use the descriptors in code-first and annotate these:

public static class Extensions
    {
        public static IObjectFieldDescriptor AllowUnauthorized(
            this IObjectFieldDescriptor descriptor)
        {
            descriptor.Directive(new AuthDirective());
            return descriptor;
        }
    }