Graph Directive

✅ See the section on Directives for a detailed explination on how directive action methods work and how to declare them.

The GraphDirective, from which all of your directives inherit, is a core object used throughout graphql. This page details some lesser known and lesser used object referenced made available to each directive.

ModelState

The completed model state dictionary with an entry for each validated parameter of the directive. The model state for the field being resolved is not accessible by the directive.

public class AllowDirective : GraphDirective
{
    public IGraphActionResult BeforeResolution(FilterModel model)
    {
        if(!this.ModelState.IsValid)
            return this.BadRequest(this.ModelState);

        //...
    }
}

Request

The individual directive request spawned from the field pipeline.

public class AllowDirective : GraphDirective
{
    public IGraphActionResult BeforeResolution(FilterModel model)
    {
        if(this.Request.SourceData is Human human)
        {
            // ...
        }
    }
}

Notable Items on the Request

• Request.Directive: Useful metadata related to the directive type being resolved.
• Request.LifeCycle: The enumeration value indicating which life cycle point is being executed.
• Request.DirectiveLocation: Indicates location in the query text this directive instance is currently being executed.
• Request.DataSource: The source data item being supplied to the field to be resolved.
• Request.Items: A collection of key/value pairs accessible to all fields and directives in this individual request pipeline.

User

The ClaimsPrincipal created by ASP.NET when this request was authorized.

public class MyCustomDirective : GraphDirective
{
    public IGraphActionResult BeforeResolution(FilterModel model)
    {
        if(this.User.Identity.Name == "DebbieEast")
        {
            // ...
        }
    }
}

Schema

The Schema property contains a reference to the singleton instance of the schema the current controller is resolving a field for. This object is considered read-only and should not be modified.

public class AllowDirective : GraphDirective
{
    public IGraphActionResult BeforeResolution(FilterModel model)
    {
        IObjectGraphType droidType = this.Schema.KnownTypes.FindGraphType(typeof(Droid), TypeKind.OBJECT);
        // ...
    }
}

caution

For type system directives, executed as part of schema construction, the schema object available may be incomplete or null. Avoid using and do not rely on the data in this.Schema for type system directives.