Directives

See Schema Directives for a detailed explanation about directives including examples on how to define them in the SDL and to create the required classes.

To add your custom SchemaDirectiveWiring to graphql-spring-boot create a bean of type SchemaDirective to have it automatically passed along to the SchemaParser

SchemaDirective.create("uppercase", new UppercaseDirective())

Basic usage

Let’s say you defined a custom directive to make text uppercase in a resource schema.graphqls:

directive @uppercase on FIELD_DEFINITION

type Query {
  hello: String @uppercase
}

And the actual implementation is the following:

public class UppercaseDirective implements SchemaDirectiveWiring {
  @Override
  public GraphQLFieldDefinition onField(SchemaDirectiveWiringEnvironment<GraphQLFieldDefinition> env) {
    GraphQLFieldDefinition field = env.getElement();
    DataFetcher dataFetcher = DataFetcherFactories.wrapDataFetcher(field.getDataFetcher(), {
      dataFetchingEnvironment, value ->
        if (value == null) {
            return null
        }
        return  ((String) value).toUpperCase()
    })
    return field.transform({ builder -> builder.dataFetcher(dataFetcher) });
  }
}

Add our custom directive as a bean:

@Bean
public SchemaDirective myCustomDirective() {
    return new SchemaDirective("uppercase", new UppercaseDirective());
}

It will then be automatically picked up and added to the SchemaParser.

Supported locations

Support for directives is currently limited to the following locations:

• OBJECT
• FIELD_DEFINITION
• ARGUMENT_DEFINITION
• INTERFACE
• UNION
• ENUM
• INPUT_OBJECT
• INPUT_FIELD_DEFINITION

Meaning directives for the following locations are currently not yet supported:

• SCALAR
• ENUM_VALUE