Class: GraphQL::Stitching::Composer

Inherits:
Object
  • Object
show all
Defined in:
lib/graphql/stitching/composer.rb

Defined Under Namespace

Classes: BaseValidator, ComposerError, ValidateBoundaries, ValidateInterfaces, ValidationError

Constant Summary collapse

NO_DEFAULT_VALUE =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

begin
  class T < GraphQL::Schema::Object
    field(:f, String) do
      argument(:a, String)
    end
  end

  T.get_field("f").get_argument("a").default_value
end
BASIC_VALUE_MERGER =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

->(values_by_location, _info) { values_by_location.values.find { !_1.nil? } }
BASIC_ROOT_FIELD_LOCATION_SELECTOR =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

->(locations, _info) { locations.last }
VALIDATORS =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

[
  "ValidateInterfaces",
  "ValidateBoundaries",
].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(query_name: "Query", mutation_name: "Mutation", description_merger: nil, deprecation_merger: nil, default_value_merger: nil, directive_kwarg_merger: nil, root_field_location_selector: nil) ⇒ Composer

Returns a new instance of Composer.



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# File 'lib/graphql/stitching/composer.rb', line 44

def initialize(
  query_name: "Query",
  mutation_name: "Mutation",
  description_merger: nil,
  deprecation_merger: nil,
  default_value_merger: nil,
  directive_kwarg_merger: nil,
  root_field_location_selector: nil
)
  @query_name = query_name
  @mutation_name = mutation_name
  @description_merger = description_merger || BASIC_VALUE_MERGER
  @deprecation_merger = deprecation_merger || BASIC_VALUE_MERGER
  @default_value_merger = default_value_merger || BASIC_VALUE_MERGER
  @directive_kwarg_merger = directive_kwarg_merger || BASIC_VALUE_MERGER
  @root_field_location_selector = root_field_location_selector || BASIC_ROOT_FIELD_LOCATION_SELECTOR
  @stitch_directives = {}

  @field_map = nil
  @boundary_map = nil
  @mapped_type_names = nil
  @candidate_directives_by_name_and_location = nil
  @schema_directives = nil
end

Instance Attribute Details

#candidate_types_by_name_and_location ⇒ Object (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/graphql/stitching/composer.rb', line 39

def candidate_types_by_name_and_location
  @candidate_types_by_name_and_location
end

#mutation_name ⇒ String (readonly)

Returns name of the Mutation type in the composed schema.

Returns:

  • (String) —

    name of the Mutation type in the composed schema.



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# File 'lib/graphql/stitching/composer.rb', line 36

def mutation_name
  @mutation_name
end

#query_name ⇒ String (readonly)

Returns name of the Query type in the composed schema.

Returns:

  • (String) —

    name of the Query type in the composed schema.



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# File 'lib/graphql/stitching/composer.rb', line 33

def query_name
  @query_name
end

#schema_directives ⇒ Object (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/graphql/stitching/composer.rb', line 42

def schema_directives
  @schema_directives
end

Instance Method Details

#perform(locations_input) ⇒ Object 



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# File 'lib/graphql/stitching/composer.rb', line 69

def perform(locations_input)
  reset!
  schemas, executables = prepare_locations_input(locations_input)

  # "directive_name" => "location" => candidate_directive
  @candidate_directives_by_name_and_location = schemas.each_with_object({}) do |(location, schema), memo|
    (schema.directives.keys - schema.default_directives.keys - GraphQL::Stitching.stitching_directive_names).each do |directive_name|
      memo[directive_name] ||= {}
      memo[directive_name][location] = schema.directives[directive_name]
    end
  end

  # "directive_name" => merged_directive
  @schema_directives = @candidate_directives_by_name_and_location.each_with_object({}) do |(directive_name, directives_by_location), memo|
    memo[directive_name] = build_directive(directive_name, directives_by_location)
  end

  @schema_directives.merge!(GraphQL::Schema.default_directives)

  # "Typename" => "location" => candidate_type
  @candidate_types_by_name_and_location = schemas.each_with_object({}) do |(location, schema), memo|
    raise ComposerError, "Location keys must be strings" unless location.is_a?(String)
    raise ComposerError, "The subscription operation is not supported." if schema.subscription

    introspection_types = schema.introspection_system.types.keys
    schema.types.each do |type_name, type_candidate|
      next if introspection_types.include?(type_name)

      if type_name == @query_name && type_candidate != schema.query
        raise ComposerError, "Query name \"#{@query_name}\" is used by non-query type in #{location} schema."
      elsif type_name == @mutation_name && type_candidate != schema.mutation
        raise ComposerError, "Mutation name \"#{@mutation_name}\" is used by non-mutation type in #{location} schema."
      end

      type_name = @query_name if type_candidate == schema.query
      type_name = @mutation_name if type_candidate == schema.mutation
      @mapped_type_names[type_candidate.graphql_name] = type_name if type_candidate.graphql_name != type_name

      memo[type_name] ||= {}
      memo[type_name][location] = type_candidate
    end
  end

  enum_usage = build_enum_usage_map(schemas.values)

  # "Typename" => merged_type
  schema_types = @candidate_types_by_name_and_location.each_with_object({}) do |(type_name, types_by_location), memo|
    kinds = types_by_location.values.map { _1.kind.name }.tap(&:uniq!)

    if kinds.length > 1
      raise ComposerError, "Cannot merge different kinds for `#{type_name}`. Found: #{kinds.join(", ")}."
    end

    extract_boundaries(type_name, types_by_location) if type_name == @query_name

    memo[type_name] = case kinds.first
    when "SCALAR"
      build_scalar_type(type_name, types_by_location)
    when "ENUM"
      build_enum_type(type_name, types_by_location, enum_usage)
    when "OBJECT"
      build_object_type(type_name, types_by_location)
    when "INTERFACE"
      build_interface_type(type_name, types_by_location)
    when "UNION"
      build_union_type(type_name, types_by_location)
    when "INPUT_OBJECT"
      build_input_object_type(type_name, types_by_location)
    else
      raise ComposerError, "Unexpected kind encountered for `#{type_name}`. Found: #{kinds.first}."
    end
  end

  builder = self
  schema = Class.new(GraphQL::Schema) do
    orphan_types schema_types.values
    query schema_types[builder.query_name]
    mutation schema_types[builder.mutation_name]
    directives builder.schema_directives.values

    own_orphan_types.clear
  end

  select_root_field_locations(schema)
  expand_abstract_boundaries(schema)

  supergraph = Supergraph.new(
    schema: schema,
    fields: @field_map,
    boundaries: @boundary_map,
    executables: executables,
  )

  VALIDATORS.each do |validator|
    klass = Object.const_get("GraphQL::Stitching::Composer::#{validator}")
    klass.new.perform(supergraph, self)
  end

  supergraph
end