Skip to main content

Operation Directives

Operation Directives provide a way to dynamically change the structure and shape of our queries using variables. An example from the GraphQL website:

query Hero($episode: Episode, $withFriends: Boolean!) {
  hero(episode: $episode) {
    name
    friends @include(if: $withFriends) {
      name
    }
  }
}

Now if you set withFriends to true in the variables passed with the query POST you'll get the friends result. If you set it to false you will not. Thus dynamically changing the shape of your query.

Built-In Directives​

The GraphQL spec defines 2 directives that are supported out of the box in EntityGraphQL.

  • @include(if: Boolean) - Only include this field in the result if the argument is true.
  • @skip(if: Boolean) - Skip this field if the argument is true.

Custom Directives​

See the IncludeDirective implementation to see how you could implement a custom directive. You can add your directive to the schema with the following

// Example only, you don't need to actually add Include or Skip directives
schema.AddDirective(new IncludeDirective());

These directives work on the internal representation of a field GraphQLQueryNode. This is working against the query graph not the data result.

There is more functionality planned for custom directives which can work on both the pre-execution query graph or the post-execution data.