class GraphQL::Schema::Directive::Transform

An example directive to show how you might interact with the runtime.

This directive takes the return value of the tagged part of the query, and if the named transform is whitelisted and applies to the return value, it’s applied by calling a method with that name.

Examples

Example: Installing the directive

class MySchema < GraphQL::Schema
  directive(GraphQL::Schema::Directive::Transform)
end

Example: Transforming strings

viewer {
  username @transform(by: "upcase")
}

Constants

TRANSFORMS

Public Class Methods

resolve (object, arguments, context) { || ... }

Source

# File lib/graphql/schema/directive/transform.rb, line 45
def self.resolve(object, arguments, context)
  path = context.namespace(:interpreter)[:current_path]
  return_value = yield
  transform_name = arguments[:by]
  if TRANSFORMS.include?(transform_name) && return_value.respond_to?(transform_name)
    return_value = return_value.public_send(transform_name)
    response = context.namespace(:interpreter_runtime)[:runtime].final_result
    *keys, last = path
    keys.each do |key|
      if response && (response = response[key])
        next
      else
        break
      end
    end
    if response
      response[last] = return_value
    end
    nil
  end
end

Implement the Directive API

resolve_field (ast_nodes, parent_type, field_defn, objects, arguments, context)

Source

# File lib/graphql/schema/directive/transform.rb, line 67
def self.resolve_field(ast_nodes, parent_type, field_defn, objects, arguments, context)
  transform_name = arguments[:by]
  if TRANSFORMS.include?(transform_name)
    Transformer.new(transform_name)
  else
    nil
  end
end