Class: GraphQL::Schema

Inherits:
Object
  • Object
show all
Includes:
Define::InstanceDefinable
Defined in:
lib/graphql/schema.rb,
lib/graphql/schema/loader.rb,
lib/graphql/schema/warden.rb,
lib/graphql/schema/printer.rb,
lib/graphql/schema/type_map.rb,
lib/graphql/schema/validation.rb,
lib/graphql/schema/reduce_types.rb,
lib/graphql/schema/possible_types.rb,
lib/graphql/schema/base_64_encoder.rb,
lib/graphql/schema/type_expression.rb,
lib/graphql/schema/middleware_chain.rb,
lib/graphql/schema/rescue_middleware.rb,
lib/graphql/schema/default_type_error.rb,
lib/graphql/schema/invalid_type_error.rb,
lib/graphql/schema/timeout_middleware.rb,
lib/graphql/schema/unique_within_type.rb,
lib/graphql/schema/catchall_middleware.rb,
lib/graphql/schema/build_from_definition.rb,
lib/graphql/schema/instrumented_field_map.rb

Overview

A GraphQL schema which may be queried with Query.

The Schema contains:

  • types for exposing your application
  • query analyzers for assessing incoming queries (including max depth & max complexity restrictions)
  • execution strategies for running incoming queries
  • middleware for interacting with execution

Schemas start with root types, #query, #mutation and #subscription. The schema will traverse the tree of fields & types, using those as starting points. Any undiscoverable types may be provided with the types configuration.

Schemas can restrict large incoming queries with max_depth and max_complexity configurations. (These configurations can be overridden by specific calls to #execute)

Schemas can specify how queries should be executed against them. query_execution_strategy, mutation_execution_strategy and subscription_execution_strategy each apply to corresponding root types.

A schema accepts a Relay::GlobalNodeIdentification instance for use with Relay IDs.

Examples:

defining a schema

MySchema = GraphQL::Schema.define do
  query QueryType
  middleware PermissionMiddleware
  rescue_from(ActiveRecord::RecordNotFound) { "Not found" }
  # If types are only connected by way of interfaces, they must be added here
  orphan_types ImageType, AudioType
end

Defined Under Namespace

Modules: Base64Encoder, BuildFromDefinition, CatchallMiddleware, DefaultTypeError, Loader, Printer, ReduceTypes, TypeExpression, UniqueWithinType Classes: InstrumentedFieldMap, InvalidDocumentError, InvalidTypeError, MiddlewareChain, PossibleTypes, RescueMiddleware, TimeoutMiddleware, TypeMap, Validation, Warden

Constant Summary collapse

BUILT_IN_TYPES = 


DIRECTIVES =



[GraphQL::Directive::IncludeDirective, GraphQL::Directive::SkipDirective, GraphQL::Directive::DeprecatedDirective]


DYNAMIC_FIELDS =



["__type", "__typename", "__schema"]




Class Attribute Summary collapse



Instance Attribute Summary collapse




Class Method Summary
collapse





Instance Method Summary
collapse




Methods included from Define::InstanceDefinable


#metadata, #redefine




Constructor Details





#initialize ⇒ Schema







Returns a new instance of Schema.















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# File 'lib/graphql/schema.rb', line 87

def initialize
  @orphan_types = []
  @directives = DIRECTIVES.reduce({}) { |m, d| m[d.name] = d; m }
  @static_validator = GraphQL::StaticValidation::Validator.new(schema: self)
  @user_middleware = []
  @query_analyzers = []
  @resolve_type_proc = nil
  @object_from_id_proc = nil
  @id_from_object_proc = nil
  @type_error_proc = DefaultTypeError
  @instrumenters = Hash.new { |h, k| h[k] = [] }
  @lazy_methods = GraphQL::Execution::Lazy::LazyMethodMap.new
  @cursor_encoder = Base64Encoder
  # Default to the built-in execution strategy:
  @query_execution_strategy = self.class.default_execution_strategy
  @mutation_execution_strategy = self.class.default_execution_strategy
  @subscription_execution_strategy = self.class.default_execution_strategy
end













Class Attribute Details






.default_execution_strategy ⇒ Object







Returns the value of attribute default_execution_strategy.















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# File 'lib/graphql/schema.rb', line 76

def default_execution_strategy
  @default_execution_strategy
end













Instance Attribute Details






#cursor_encoder ⇒ Object







Returns the value of attribute cursor_encoder.















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# File 'lib/graphql/schema.rb', line 67

def cursor_encoder
  @cursor_encoder
end













#directives ⇒ Object







Returns the value of attribute directives.















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# File 'lib/graphql/schema.rb', line 67

def directives
  @directives
end













#id_from_object_proc ⇒ Object (readonly)







Returns the value of attribute id_from_object_proc.















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# File 'lib/graphql/schema.rb', line 85

def id_from_object_proc
  @id_from_object_proc
end













#instrumenters ⇒ Object







Returns the value of attribute instrumenters.















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# File 'lib/graphql/schema.rb', line 67

def instrumenters
  @instrumenters
end













#lazy_methods ⇒ Object







Returns the value of attribute lazy_methods.















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# File 'lib/graphql/schema.rb', line 67

def lazy_methods
  @lazy_methods
end













#max_complexity ⇒ Object







Returns the value of attribute max_complexity.















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# File 'lib/graphql/schema.rb', line 67

def max_complexity
  @max_complexity
end













#max_depth ⇒ Object







Returns the value of attribute max_depth.















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# File 'lib/graphql/schema.rb', line 67

def max_depth
  @max_depth
end













#mutation ⇒ Object







Returns the value of attribute mutation.















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# File 'lib/graphql/schema.rb', line 67

def mutation
  @mutation
end













#mutation_execution_strategy ⇒ Object







Returns the value of attribute mutation_execution_strategy.















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# File 'lib/graphql/schema.rb', line 67

def mutation_execution_strategy
  @mutation_execution_strategy
end













#object_from_id_proc ⇒ Object (readonly)







Returns the value of attribute object_from_id_proc.















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# File 'lib/graphql/schema.rb', line 85

def object_from_id_proc
  @object_from_id_proc
end













#orphan_types ⇒ Object







Returns the value of attribute orphan_types.















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# File 'lib/graphql/schema.rb', line 67

def orphan_types
  @orphan_types
end













#query ⇒ Object







Returns the value of attribute query.















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# File 'lib/graphql/schema.rb', line 67

def query
  @query
end













#query_analyzers ⇒ Object







Returns the value of attribute query_analyzers.















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# File 'lib/graphql/schema.rb', line 67

def query_analyzers
  @query_analyzers
end













#query_execution_strategy ⇒ Object







Returns the value of attribute query_execution_strategy.















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# File 'lib/graphql/schema.rb', line 67

def query_execution_strategy
  @query_execution_strategy
end













#resolve_type_proc ⇒ Object (readonly)







Returns the value of attribute resolve_type_proc.















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# File 'lib/graphql/schema.rb', line 85

def resolve_type_proc
  @resolve_type_proc
end













#static_validator ⇒ Object (readonly)







Returns the value of attribute static_validator.















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# File 'lib/graphql/schema.rb', line 85

def static_validator
  @static_validator
end













#subscription ⇒ Object







Returns the value of attribute subscription.















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# File 'lib/graphql/schema.rb', line 67

def subscription
  @subscription
end













#subscription_execution_strategy ⇒ Object







Returns the value of attribute subscription_execution_strategy.















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# File 'lib/graphql/schema.rb', line 67

def subscription_execution_strategy
  @subscription_execution_strategy
end













#user_middleware ⇒ Object







Returns the value of attribute user_middleware.















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# File 'lib/graphql/schema.rb', line 67

def user_middleware
  @user_middleware
end













Class Method Details





.from_definition(definition_string) ⇒ GraphQL::Schema







Create schema from an IDL schema.








Parameters:


    

  • 
definition_string

—

    String A schema definition string
    

    

    • 



Returns:










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# File 'lib/graphql/schema.rb', line 335

def self.from_definition(definition_string)
  GraphQL::Schema::BuildFromDefinition.from_definition(definition_string)
end












.from_introspection(introspection_result) ⇒ GraphQL::Schema







Create schema with the result of an introspection query.








Parameters:



Returns:










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# File 'lib/graphql/schema.rb', line 328

def self.from_introspection(introspection_result)
  GraphQL::Schema::Loader.load(introspection_result)
end













Instance Method Details





#define(**kwargs, &block) ⇒ Object










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# File 'lib/graphql/schema.rb', line 142

def define(**kwargs, &block)
  super
  ensure_defined
  build_types_map
  # Assert that all necessary configs are present:
  validation_error = Validation.validate(self)
  validation_error && raise(NotImplementedError, validation_error)
  build_instrumented_field_map
  nil
end












#execute(*args) ⇒ Hash







Execute a query on itself.
See Query#initialize for arguments.








Returns:


    

  • 
(Hash)
—

    query result, ready to be serialized as JSON
    

    

    • 










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# File 'lib/graphql/schema.rb', line 173

def execute(*args)
  query_obj = GraphQL::Query.new(self, *args)
  query_obj.result
end












#execution_strategy_for_operation(operation) ⇒ Object










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# File 'lib/graphql/schema.rb', line 222

def execution_strategy_for_operation(operation)
  case operation
  when "query"
    query_execution_strategy
  when "mutation"
    mutation_execution_strategy
  when "subscription"
    subscription_execution_strategy
  else
    raise ArgumentError, "unknown operation type: #{operation}"
  end
end












#get_field(parent_type, field_name) ⇒ GraphQL::Field?







Resolve field named field_name for type parent_type.
Handles dynamic fields __typename, __type and __schema, too








Returns:



See Also:


    

  • Restricted access to members of a schema
    • 










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# File 'lib/graphql/schema.rb', line 182

def get_field(parent_type, field_name)
  defined_field = @instrumented_field_map.get(parent_type.name, field_name)
  if defined_field
    defined_field
  elsif field_name == "__typename"
    GraphQL::Introspection::TypenameField.create(parent_type)
  elsif field_name == "__schema" && parent_type == query
    GraphQL::Introspection::SchemaField.create(self)
  elsif field_name == "__type" && parent_type == query
    GraphQL::Introspection::TypeByNameField.create(self)
  else
    nil
  end
end












#id_from_object(object, type, ctx) ⇒ String







Get a unique identifier from this object








Parameters:



Returns:


    

  • 
(String)
—

    a unique identifier for object which clients can use to refetch it
    

    

    • 










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# File 'lib/graphql/schema.rb', line 312

def id_from_object(object, type, ctx)
  if @id_from_object_proc.nil?
    raise(NotImplementedError, "Can't generate an ID for #{object.inspect} of type #{type}, schema's `id_from_object` must be defined")
  else
    @id_from_object_proc.call(object, type, ctx)
  end
end












#id_from_object=(new_proc) ⇒ Object













Parameters:


    

  • 
new_proc
(#call)
—

    A new callable for generating unique IDs
    

    

    • 










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# File 'lib/graphql/schema.rb', line 321

def id_from_object=(new_proc)
  @id_from_object_proc = new_proc
end












#initialize_copy(other) ⇒ Object










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# File 'lib/graphql/schema.rb', line 106

def initialize_copy(other)
  super
  @orphan_types = other.orphan_types.dup
  @directives = other.directives.dup
  @static_validator = GraphQL::StaticValidation::Validator.new(schema: self)
  @user_middleware = other.user_middleware.dup
  @middleware = nil
  @query_analyzers = other.query_analyzers.dup

  @possible_types = GraphQL::Schema::PossibleTypes.new(self)

  @lazy_methods = GraphQL::Execution::Lazy::LazyMethodMap.new
  other.lazy_methods.each { |lazy_class, lazy_method| @lazy_methods.set(lazy_class, lazy_method) }

  @instrumenters = Hash.new { |h, k| h[k] = [] }
  other.instrumenters.each do |key, insts|
    @instrumenters[key].concat(insts)
  end

  if other.rescues?
    @rescue_middleware = other.rescue_middleware
  end

  # This will be rebuilt when it's requested
  # or during a later `define` call
  @types = nil
end












#instrument(instrumentation_type, instrumenter) ⇒ void







This method returns an undefined value.
Attach instrumenter to this schema for instrumenting events of instrumentation_type.








Parameters:


    

  • 
instrumentation_type
(Symbol)

    • 

  • 
instrumenter


    • 










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# File 'lib/graphql/schema.rb', line 157

def instrument(instrumentation_type, instrumenter)
  @instrumenters[instrumentation_type] << instrumenter
  if instrumentation_type == :field
    build_instrumented_field_map
  end
end












#lazy?(obj) ⇒ Boolean







Returns True if this object should be lazily resolved.








Returns:


    

  • 
(Boolean)
—

    True if this object should be lazily resolved
    

    

    • 










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# File 'lib/graphql/schema.rb', line 348

def lazy?(obj)
  !!lazy_method_name(obj)
end












#lazy_method_name(obj) ⇒ Symbol?







Returns The method name to lazily resolve obj, or nil if obj's class wasn't registered wtih #lazy_resolve.








Returns:


    

  • 
(Symbol, nil)
—

    The method name to lazily resolve obj, or nil if obj's class wasn't registered wtih #lazy_resolve.
    

    

    • 










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# File 'lib/graphql/schema.rb', line 343

def lazy_method_name(obj)
  @lazy_methods.get(obj)
end












#middleware ⇒ Array<#call>







Returns Middlewares suitable for MiddlewareChain, applied to fields during execution.








Returns:


    

  • 
(Array<#call>)
—

    Middlewares suitable for MiddlewareChain, applied to fields during execution
    

    

    • 










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# File 'lib/graphql/schema.rb', line 353

def middleware
  @middleware ||= if @rescue_middleware
    [@rescue_middleware].concat(@user_middleware)
  else
    @user_middleware
  end
end












#object_from_id(id, ctx) ⇒ Any







Fetch an application object by its unique id








Parameters:


    

  • 
id
(String)
—

    A unique identifier, provided previously by this GraphQL schema
    

    

    • 

  • 
ctx
(GraphQL::Query::Context)
—

    The context for the current query
    

    

    • 



Returns:


    

  • 
(Any)
—

    The application object identified by id
    

    

    • 










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# File 'lib/graphql/schema.rb', line 265

def object_from_id(id, ctx)
  if @object_from_id_proc.nil?
    raise(NotImplementedError, "Can't fetch an object for id \"#{id}\" because the schema's `object_from_id (id, ctx) -> { ... }` function is not defined")
  else
    @object_from_id_proc.call(id, ctx)
  end
end












#object_from_id=(new_proc) ⇒ Object













Parameters:


    

  • 
new_proc
(#call)
—

    A new callable for fetching objects by ID
    

    

    • 










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# File 'lib/graphql/schema.rb', line 274

def object_from_id=(new_proc)
  @object_from_id_proc = new_proc
end












#possible_types(type_defn) ⇒ Array<GraphQL::ObjectType>







Returns types which belong to type_defn in this schema.








Parameters:



Returns:



See Also:


    

  • Restricted access to members of a schema
    • 










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# File 'lib/graphql/schema.rb', line 204

def possible_types(type_defn)
  @possible_types ||= GraphQL::Schema::PossibleTypes.new(self)
  @possible_types.possible_types(type_defn)
end












#remove_handler(*args, &block) ⇒ Object










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# File 'lib/graphql/schema.rb', line 138

def remove_handler(*args, &block)
  rescue_middleware.remove_handler(*args, &block)
end












#rescue_from(*args, &block) ⇒ Object










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# File 'lib/graphql/schema.rb', line 134

def rescue_from(*args, &block)
  rescue_middleware.rescue_from(*args, &block)
end












#resolve_type(object, ctx) ⇒ GraphQL::ObjectType







Determine the GraphQL type for a given object.
This is required for unions and interfaces (including Relay's Node interface)








Parameters:


    

  • 
object
(Any)
—

    An application object which GraphQL is currently resolving on
    

    

    • 

  • 
ctx
(GraphQL::Query::Context)
—

    The context for the current query
    

    

    • 



Returns:



See Also:


    

  • Restricted access to members of a schema
    • 










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# File 'lib/graphql/schema.rb', line 241

def resolve_type(object, ctx)
  if @resolve_type_proc.nil?
    raise(NotImplementedError, "Can't determine GraphQL type for: #{object.inspect}, define `resolve_type (obj, ctx) -> { ... }` inside `Schema.define`.")
  end

  type_result = @resolve_type_proc.call(object, ctx)
  if type_result.nil?
    nil
  elsif !type_result.is_a?(GraphQL::BaseType)
    type_str = "#{type_result} (#{type_result.class.name})"
    raise "resolve_type(#{object}) returned #{type_str}, but it should return a GraphQL type"
  else
    type_result
  end
end












#resolve_type=(new_resolve_type_proc) ⇒ Object










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# File 'lib/graphql/schema.rb', line 257

def resolve_type=(new_resolve_type_proc)
  @resolve_type_proc = new_resolve_type_proc
end












#root_type_for_operation(operation) ⇒ Object










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# File 'lib/graphql/schema.rb', line 209

def root_type_for_operation(operation)
  case operation
  when "query"
    query
  when "mutation"
    mutation
  when "subscription"
    subscription
  else
    raise ArgumentError, "unknown operation type: #{operation}"
  end
end












#type_error(err, ctx) ⇒ Object







When we encounter a type error during query execution, we call this hook.


You can use this hook to write a log entry,
add a ExecutionError to the response (with ctx.add_error)
or raise an exception and halt query execution.










Examples:


A nil is encountered by a non-null field




type_error ->(err, query_ctx) {
  err.is_a?(GraphQL::InvalidNullError) # => true
}


An object doesn't resolve to one of a UnionType's members




type_error ->(err, query_ctx) {
  err.is_a?(GraphQL::UnresolvedTypeError) # => true
}




Parameters:


    

  • 
err
(GraphQL::TypeError)
—

    The error encountered during execution
    

    

    • 

  • 
ctx
(GraphQL::Query::Context)
—

    The context for the field where the error occurred
    

    

    • 



Returns:


    

  • 


    void
    

    

    • 



See Also:


    

  • is the default behavior.
    • 










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# File 'lib/graphql/schema.rb', line 298

def type_error(err, ctx)
  @type_error_proc.call(err, ctx)
end












#type_error=(new_proc) ⇒ Object













Parameters:


    

  • 
new_proc
(#call)
—

    A new callable for handling type errors during execution
    

    

    • 










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# File 'lib/graphql/schema.rb', line 303

def type_error=(new_proc)
  @type_error_proc = new_proc
end












#type_from_ast(ast_node) ⇒ Object










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# File 'lib/graphql/schema.rb', line 197

def type_from_ast(ast_node)
  GraphQL::Schema::TypeExpression.build_type(self.types, ast_node)
end












#types ⇒ GraphQL::Schema::TypeMap







Returns { name => type } pairs of types in this schema.








Returns:



See Also:


    

  • Restricted access to members of a schema
    • 










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# File 'lib/graphql/schema.rb', line 166

def types
  @types ||= build_types_map
end