class GraphQL::Schema::FieldExtension

Extend this class to make field-level customizations to resolve behavior.

When a extension is added to a field with extension(MyExtension), a MyExtension instance is created, and its hooks are applied whenever that field is called.

The instance is frozen so that instance variables aren’t modified during query execution, which could cause all kinds of issues due to race conditions.

Attributes

added_default_arguments [R]

Returns

Array<Symbol>, nil — default_arguments added, if any were added (otherwise, nil)

field [R]

Returns

GraphQL::Schema::Field

options [R]

Returns

Object

Public Class Methods

default_argument (*argument_args, **argument_kwargs)

Source

# File lib/graphql/schema/field_extension.rb, line 66
def default_argument(*argument_args, **argument_kwargs)
  configs = @own_default_argument_configurations ||= []
  configs << [argument_args, argument_kwargs]
end

See the GraphQL::Schema::Argument API. See HasArguments#argument for argument configuration.

default_argument_configurations() → Array(Array, Hash) | nil

Source

# File lib/graphql/schema/field_extension.rb, line 52
def default_argument_configurations
  args = superclass.respond_to?(:default_argument_configurations) ? superclass.default_argument_configurations : nil
  if @own_default_argument_configurations
    if args
      args.concat(@own_default_argument_configurations)
    else
      args = @own_default_argument_configurations.dup
    end
  end
  args
end

Returns

Array(Array, Hash), nil — A list of default argument configs, or nil if there aren’t any

extras(Array[Symbol] new_extras) → Array[Symbol]

Source

# File lib/graphql/schema/field_extension.rb, line 85
def extras(new_extras = nil)
  if new_extras
    @own_extras = new_extras
  end

  inherited_extras = self.superclass.respond_to?(:extras) ? superclass.extras : nil
  if @own_extras
    if inherited_extras
      inherited_extras + @own_extras
    else
      @own_extras
    end
  elsif inherited_extras
    inherited_extras
  else
    GraphQL::EmptyObjects::EMPTY_ARRAY
  end
end

If configured, these extras will be added to the field if they aren’t already present, but removed by from arguments before the field’s resolve is called. (The extras will be present for other extensions, though.)

Parameters

new_extras (Array<Symbol>) — If provided, assign extras used by this extension

Returns

Array<Symbol> — any extras assigned to this extension

initialize(GraphQL::Schema::Field field:, Object options:)

Source

# File lib/graphql/schema/field_extension.rb, line 38
def initialize(field:, options:)
  @field = field
  @options = options || {}
  @added_default_arguments = nil
  apply
end

Called when the extension is mounted with extension(name, options). The instance will be frozen to avoid improper use of state during execution.

Parameters

field (GraphQL::Schema::Field) — The field where this extension was mounted
options (Object) — The second argument to extension, or {} if nothing was passed.

Public Instance Methods

after_define() → void

Source

# File lib/graphql/schema/field_extension.rb, line 126
def after_define
end

Called after the field’s definition block has been executed. (Any arguments from the block are present on field)

Returns

void

after_resolve(Object object:, Array[Object] objects:, Hash arguments:, Query::Context context:, Array[Object] values:, Object value:, Object memo:) → Object

Source

# File lib/graphql/schema/field_extension.rb, line 206
def after_resolve(object: nil, objects: nil, arguments:, context:, values: nil, value: nil, memo:)
  value.nil? ? values : value
end

Called after field was resolved, and after any lazy values (like Promises) were synced, but before the value was added to the GraphQL response.

Whatever this hook returns will be used as the return value.

Parameters

object (Object) — The object the field is being resolved on (not passed by new execution)
objects (Array<Object>) — The object the field is being resolved on (passed by new execution)
arguments (Hash) — Ruby keyword arguments for resolving this field
context (Query::Context) — the context for this query
value (Object) — Whatever the field previously returned (not passed by new execution)
values (Array<Object>) — Whatever the field previously returned (passed by new execution)
memo (Object) — The third value yielded by resolve, or nil if there wasn’t one

Returns

Object — The return value for this field.

apply() → void

Source

# File lib/graphql/schema/field_extension.rb, line 114
def apply
end

Called when this extension is attached to a field. The field definition may be extended during this method.

Returns

void

resolve(Object object:, Array[Object] objects:, Hash arguments:, Query::Context context:) → Object

Source

# File lib/graphql/schema/field_extension.rb, line 181
def resolve(object: nil, objects: nil, arguments:, context:)
  yield(object.nil? ? objects : object, arguments, nil)
end

Called before resolving field. It should either:

yield values to continue execution; OR
return something else to shortcut field execution.

Whatever this method returns will be used for execution.

Parameters

object (Object) — The object the field is being resolved on (not passed by new execution)
objects (Array<Object>) — The objects the field is being resolved on (passed by new execution)
arguments (Hash) — Ruby keyword arguments for resolving this field
context (Query::Context) — the context for this query

Yields

object_or_objects (Object, Array<Object>) — The object or objects (new execution) to continue resolving the field on
arguments (Hash) — The keyword arguments to continue resolving with
memo (Object) — Any extension-specific value which will be passed to after resolve later

Returns

Object — The return value for this field.