Support for Default Values on INPUT_OBJECT fields about graphql-aspnet HOT 2 CLOSED

After further thought the extra values in the [GraphFIeld] are not necessary. As of today, since all INPUT_OBJECT types are first created from a parameterless constructor there exists an opportunity for developer code to set any necessary values. We only then need the ability to mark fields as non-nullable when they otherwise would be due to type constraints. This is mostly around value types such as int, double etc.

While it is possible today to mark a field as required or not using the [GraphField] attribute its a bit limiting and not very intuitive.

• [GraphField(TypeExpressions= TypeExpressions.None)]
  • Will Mark an otherwise required property (such as an int) as being not required
• [GraphField(TypeExpressions= TypeExpressions.IsNotNullable)]
  • Will mark a nullable property (such as a reference) as being required.

Since declaring a type expression overrides what the templating engine would glean about the property return type, you run into trouble if the property is a list. You would have to redeclare the entire list structure as part of the TypeExpression field in order to maintain its correctness if you wished to apply "non-nullability" to the list.

This is exceedingly cumbersome and verbose.

Proposal (Breaking Change):

It is in error to force an value type property to be required in a query unless otherwise stated by the user.

Take a page from ASP.NET and the use of [Required] (from System.ComponentModel) for deserializing objects during rest queries. If a field is attributed with [Required]then it must be supplied. Otherwise its value will be set to whatever is the value of default(Type) is or a value supplied during the object's constructor.

This would be a breaking change in that it changes the default behavior for value type fields on INPUT_OBJECT types. However, in the spirit of conforming to ASP.NET standards and general expectations of ASP.NET developers, this change should prove better in the long run.

// assume this class is registered as an INPUT_OBJECT
public class Person
{
   Person()
   {
      this.IsHappy = true; // set a default value during object creation
      this.Child = null;
   }

   // NOT required in a query
   // Expresssion:  'String'
   // Default Value:  <null>  | as defined by default(string)
   public string FirstName { get; set; }

   // REQUIRED in a query
   // Expresssion:  'String!'
   // Default Value:  -Not defined-
   [Required]
   public string LastName { get; set; }

   // REQUIRED in a query
   // Expresssion:  'Address!'
   // Default Value:  -Not defined-
   [Required]
   public Address Address { get; set; }

   // NOT REQUIRED in a query
   // Expresssion:  'Person'
   // Default Value:  null  | as set in the constructor
   public Person Child { get; set; }

   // NOT REQUIRED in a query
   // Expresssion:  'Bool'
   // Default Value:  true  | as set in the constructor
   public bool IsHappy { get; set; }

   // NOT REQUIRED in a query
   // Expresssion:  'Int'
   // Default Value:  0  | as set by default(int)
   public int Age{  get; set; }

   // REQUIRED in a query
   // Expresssion:  'Int!'
   // Default Value:  - Not Defined -
   [Required]
   public int BirthOrder { get; set; }
}

from graphql-aspnet.

released as part of v0.12.0-beta

from graphql-aspnet.