Class: GraphQL::UnionType

Inherits:
BaseType show all
Defined in:
lib/graphql/union_type.rb

Overview

A Union is is a collection of object types which may appear in the same place.

The members of a union are declared with possible_types.

A union itself has no fields; only its members have fields. So, when you query, you must use fragment spreads to access fields.

Examples:

A union of object types

MediaUnion = GraphQL::UnionType.define do
  name "Media"
  description "Media objects which you can enjoy"
  possible_types [AudioType, ImageType, VideoType]
end

Querying for fields on union members

{
  searchMedia(name: "Jens Lekman") {
    ... on Audio { name, duration }
    ... on Image { name, height, width }
    ... on Video { name, length, quality }
  }
}

Instance Attribute Summary collapse

Attributes inherited from BaseType

#ast_node, #default_relay, #default_scalar, #description, #introspection, #name

Instance Method Summary collapse

Methods inherited from BaseType

#==, #coerce_input, #coerce_isolated_input, #coerce_isolated_result, #coerce_result, #default_relay?, #default_scalar?, #get_field, #introspection?, #list?, #non_null?, resolve_related_type, #to_definition, #to_list_type, #to_non_null_type, #to_s, #unwrap, #valid_input?, #valid_isolated_input?, #validate_input, #validate_isolated_input

Methods included from Relay::TypeExtensions

#connection_type, #define_connection, #define_edge, #edge_type

Methods included from Define::InstanceDefinable

#define, #metadata, #redefine

Methods included from Define::NonNullWithBang

#!

Constructor Details

#initialize ⇒ UnionType

Returns a new instance of UnionType



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# File 'lib/graphql/union_type.rb', line 35

def initialize
  super
  @type_membership_class = GraphQL::Schema::TypeMembership
  @type_memberships = []
  @cached_possible_types = nil
  @resolve_type_proc = nil
end

Instance Attribute Details

#resolve_type_proc ⇒ Object

Returns the value of attribute resolve_type_proc



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# File 'lib/graphql/union_type.rb', line 31

def resolve_type_proc
  @resolve_type_proc
end

#type_membership_class ⇒ Object

Returns the value of attribute type_membership_class



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# File 'lib/graphql/union_type.rb', line 33

def type_membership_class
  @type_membership_class
end

#type_memberships ⇒ Object

Returns the value of attribute type_memberships



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# File 'lib/graphql/union_type.rb', line 32

def type_memberships
  @type_memberships
end

Instance Method Details

#add_possible_types(types, options) ⇒ Object 



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# File 'lib/graphql/union_type.rb', line 78

def add_possible_types(types, options)
  @type_memberships ||= []
  Array(types).each { |t|
    @type_memberships << self.type_membership_class.new(self, t, options)
  }
  nil
end

#get_possible_type(type_name, ctx) ⇒ GraphQL::ObjectType?

Get a possible type of this GraphQL::UnionType by type name

Parameters:

Returns:



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# File 'lib/graphql/union_type.rb', line 90

def get_possible_type(type_name, ctx)
  type = ctx.query.get_type(type_name)
  type if type && ctx.query.schema.possible_types(self, ctx).include?(type)
end

#include?(child_type_defn, ctx = GraphQL::Query::NullContext) ⇒ Boolean

Returns True if child_type_defn is a member of this GraphQL::UnionType

Returns:



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# File 'lib/graphql/union_type.rb', line 55

def include?(child_type_defn, ctx = GraphQL::Query::NullContext)
  possible_types(ctx).include?(child_type_defn)
end

#initialize_copy(other) ⇒ Object 



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# File 'lib/graphql/union_type.rb', line 43

def initialize_copy(other)
  super
  @type_membership_class = other.type_membership_class
  @type_memberships = other.type_memberships.dup
  @cached_possible_types = nil
end

#kind ⇒ Object 



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# File 'lib/graphql/union_type.rb', line 50

def kind
  GraphQL::TypeKinds::UNION
end

#possible_type?(type, ctx) ⇒ Boolean

Check if a type is a possible type of this GraphQL::UnionType

Parameters:

Returns:

  • (Boolean) —

    True if the type exists and is a member of this GraphQL::UnionType, (else nil)



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# File 'lib/graphql/union_type.rb', line 99

def possible_type?(type, ctx)
  type_name = type.is_a?(String) ? type : type.graphql_name
  !get_possible_type(type_name, ctx).nil?
end

#possible_types(ctx = GraphQL::Query::NullContext) ⇒ Array<GraphQL::ObjectType>

Returns Types which may be found in this union

Returns:



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# File 'lib/graphql/union_type.rb', line 60

def possible_types(ctx = GraphQL::Query::NullContext)
  if ctx == GraphQL::Query::NullContext
    # Only cache the default case; if we cached for every `ctx`, it would be a memory leak
    # (The warden should cache calls to this method, so it's called only once per query,
    # unless user code calls it directly.)
    @cached_possible_types ||= possible_types_for_context(ctx)
  else
    possible_types_for_context(ctx)
  end
end

#possible_types=(types) ⇒ Object 



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# File 'lib/graphql/union_type.rb', line 71

def possible_types=(types)
  # This is a re-assignment, so clear the previous values
  @type_memberships = []
  @cached_possible_types = nil
  add_possible_types(types, {})
end

#resolve_type(value, ctx) ⇒ Object 



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# File 'lib/graphql/union_type.rb', line 104

def resolve_type(value, ctx)
  ctx.query.resolve_type(self, value)
end

#resolve_type=(new_resolve_type_proc) ⇒ Object 



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# File 'lib/graphql/union_type.rb', line 108

def resolve_type=(new_resolve_type_proc)
  @resolve_type_proc = new_resolve_type_proc
end