Class: GraphQL::Schema::Field

Inherits:
Object
  • Object
show all
Includes:
Member::AcceptsDefinition, Member::CachedGraphQLDefinition, Member::HasArguments
Defined in:
lib/graphql/schema/field.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Member::HasArguments

#argument, #argument_class, #arguments, #own_arguments

Methods included from Member::CachedGraphQLDefinition

#graphql_definition, #initialize_copy

Constructor Details

#initialize(type: nil, name: nil, owner: nil, null: nil, field: nil, function: nil, description: nil, deprecation_reason: nil, method: nil, connection: nil, max_page_size: nil, resolve: nil, introspection: false, hash_key: nil, camelize: true, complexity: 1, extras: [], resolver_class: nil, subscription_scope: nil, arguments: {}, &definition_block) ⇒ Field

Returns a new instance of Field

Parameters:

  • name (Symbol) —

    The underscore-cased version of this field name (will be camelized for the GraphQL API)

  • return_type_expr (Class, GraphQL::BaseType, Array) —

    The return type of this field

  • desc (String) —

    Field description

  • owner (Class) —

    The type that this field belongs to

  • null (Boolean) —

    true if this field may return null, false if it is never null

  • description (String) —

    Field description

  • deprecation_reason (String) —

    If present, the field is marked “deprecated” with this message

  • method (Symbol) —

    The method to call to resolve this field (defaults to name)

  • hash_key (Object) —

    The hash key to lookup to resolve this field (defaults to name or name.to_s)

  • connection (Boolean) —

    true if this field should get automagic connection behavior; default is to infer by *Connection in the return type name

  • max_page_size (Integer) —

    For connections, the maximum number of items to return from this field

  • introspection (Boolean) —

    If true, this field will be marked as #introspection? and the name may begin with __

  • resolve (<#call(obj, args, ctx)>) —

    deprecated for compatibility with <1.8.0

  • field (GraphQL::Field, GraphQL::Schema::Field) —

    deprecated for compatibility with <1.8.0

  • function (GraphQL::Function) —

    deprecated for compatibility with <1.8.0

  • resolver_class (Class) —

    (Private) A Resolver which this field was derived from. Use resolver: to create a field with a resolver.

  • arguments ({String=>GraphQL::Schema::Argument, Hash}) —

    Arguments for this field (may be added in the block, also)

  • camelize (Boolean) —

    If true, the field name will be camelized when building the schema

  • complexity (Numeric) —

    When provided, set the complexity for this field

  • subscription_scope (Symbol, String) —

    A key in context which will be used to scope subscription payloads



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# File 'lib/graphql/schema/field.rb', line 96

def initialize(type: nil, name: nil, owner: nil, null: nil, field: nil, function: nil, description: nil, deprecation_reason: nil, method: nil, connection: nil, max_page_size: nil, resolve: nil, introspection: false, hash_key: nil, camelize: true, complexity: 1, extras: [], resolver_class: nil, subscription_scope: nil, arguments: {}, &definition_block)

  if name.nil?
    raise ArgumentError, "missing first `name` argument or keyword `name:`"
  end
  if !(field || function || mutation || resolver)
    if type.nil?
      raise ArgumentError, "missing second `type` argument or keyword `type:`"
    end
    if null.nil?
      raise ArgumentError, "missing keyword argument null:"
    end
  end
  if (field || function || resolve || mutation) && extras.any?
    raise ArgumentError, "keyword `extras:` may only be used with method-based resolve, please remove `field:`, `function:`, `resolve:`, or `mutation:`"
  end
  @name = camelize ? Member::BuildType.camelize(name.to_s) : name.to_s
  @description = description
  if field.is_a?(GraphQL::Schema::Field)
    @field_instance = field
  else
    @field = field
  end
  @function = function
  @resolve = resolve
  @deprecation_reason = deprecation_reason
  if method && hash_key
    raise ArgumentError, "Provide `method:` _or_ `hash_key:`, not both. (called with: `method: #{method.inspect}, hash_key: #{hash_key.inspect}`)"
  end

  # TODO: I think non-string/symbol hash keys are wrongly normalized (eg `1` will not work)
  method_name = method || hash_key || Member::BuildType.underscore(name.to_s)

  @method_str = method_name.to_s
  @method_sym = method_name.to_sym
  @complexity = complexity
  @return_type_expr = type
  @return_type_null = null
  @connection = connection
  @max_page_size = max_page_size
  @introspection = introspection
  @extras = extras
  @resolver_class = resolver_class

  # Override the default from HasArguments
  @own_arguments = {}
  arguments.each do |name, arg|
    if arg.is_a?(Hash)
      argument(name: name, **arg)
    else
      @own_arguments[name] = arg
    end
  end

  @owner = owner
  @subscription_scope = subscription_scope

  if definition_block
    instance_eval(&definition_block)
  end
end

Instance Attribute Details

#description(text = nil) ⇒ String

Returns:

  • (String) 


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# File 'lib/graphql/schema/field.rb', line 14

def description
  @description
end

#method_str ⇒ String (readonly)

Returns Method or hash key to look up

Returns:

  • (String) —

    Method or hash key to look up



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# File 'lib/graphql/schema/field.rb', line 20

def method_str
  @method_str
end

#method_sym ⇒ Symbol (readonly)

Returns Method or hash key to look up

Returns:

  • (Symbol) —

    Method or hash key to look up



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# File 'lib/graphql/schema/field.rb', line 17

def method_sym
  @method_sym
end

#name ⇒ String

Returns the GraphQL name for this field, camelized unless camelize: false is provided

Returns:

  • (String) —

    the GraphQL name for this field, camelized unless camelize: false is provided



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# File 'lib/graphql/schema/field.rb', line 11

def name
  @name
end

#owner ⇒ Class (readonly)

Returns The type that this field belongs to

Returns:

  • (Class) —

    The type that this field belongs to



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# File 'lib/graphql/schema/field.rb', line 23

def owner
  @owner
end

Class Method Details

.from_options(name = nil, type = nil, desc = nil, resolver: nil, mutation: nil, **kwargs, &block) ⇒ GraphQL::Schema:Field

Create a field instance from a list of arguments, keyword arguments, and a block.

This method implements prioritization between the resolver or mutation defaults and the local overrides via other keywords.

It also normalizes positional arguments into keywords for #initialize.

Parameters:

  • resolver (Class) —

    A Resolver class to use for field configuration

  • mutation (Class) —

    A Mutation class to use for field configuration

Returns:

  • (GraphQL::Schema:Field) —

    an instance of `self

See Also:

  • for other options


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# File 'lib/graphql/schema/field.rb', line 43

def self.from_options(name = nil, type = nil, desc = nil, resolver: nil, mutation: nil, **kwargs, &block)
  if (parent_config = resolver || mutation)
    # Get the parent config, merge in local overrides
    kwargs = parent_config.field_options.merge(kwargs)
    # Add a reference to that parent class
    kwargs[:resolver_class] = parent_config
  end

  if name
    kwargs[:name] = name
  end

  if !type.nil?
    if type.is_a?(GraphQL::Field)
      raise ArgumentError, "A GraphQL::Field was passed as the second argument, use the `field:` keyword for this instead."
    end
    if desc
      if kwargs[:description]
        raise ArgumentError, "Provide description as a positional argument or `description:` keyword, but not both (#{desc.inspect}, #{kwargs[:description].inspect})"
      end

      kwargs[:description] = desc
      kwargs[:type] = type
    elsif (kwargs[:field] || kwargs[:function] || resolver || mutation) && type.is_a?(String)
      # The return type should be copied from `field` or `function`, and the second positional argument is the description
      kwargs[:description] = type
    else
      kwargs[:type] = type
    end
  end
  new(**kwargs, &block)
end

Instance Method Details

#complexity(new_complexity) ⇒ Object 



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

def complexity(new_complexity)
  case new_complexity
  when Proc
    if new_complexity.parameters.size != 3
      fail(
        "A complexity proc should always accept 3 parameters: ctx, args, child_complexity. "\
        "E.g.: complexity ->(ctx, args, child_complexity) { child_complexity * args[:limit] }"
      )
    else
      @complexity = new_complexity
    end
  when Numeric
    @complexity = new_complexity
  else
    raise("Invalid complexity: #{new_complexity.inspect} on #{@name}")
  end

end

#resolve_field(obj, args, ctx) ⇒ Object

Implement Field’s resolve API.

Eventually, we might hook up field instances to execution in another way. TBD.



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# File 'lib/graphql/schema/field.rb', line 280

def resolve_field(obj, args, ctx)
  if @resolve_proc
    # Might be nil, still want to call the func in that case
    inner_obj = obj && obj.object
    @resolve_proc.call(inner_obj, args, ctx)
  elsif @resolver_class
    inner_obj = obj && obj.object
    singleton_inst = @resolver_class.new(object: inner_obj, context: ctx.query.context)
    public_send_field(singleton_inst, args, ctx)
  else
    public_send_field(obj, args, ctx)
  end
end

#resolve_field_method(obj, ruby_kwargs, ctx) ⇒ Object

Find a way to resolve this field, checking:

  • Hash keys, if the wrapped object is a hash;
  • A method on the wrapped object;
  • Or, raise not implemented.

This can be overridden by defining a method on the object type.

Parameters:



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# File 'lib/graphql/schema/field.rb', line 304

def resolve_field_method(obj, ruby_kwargs, ctx)
  if obj.object.is_a?(Hash)
    inner_object = obj.object
    if inner_object.key?(@method_sym)
      inner_object[@method_sym]
    else
      inner_object[@method_str]
    end
  elsif obj.object.respond_to?(@method_sym)
    if ruby_kwargs.any?
      obj.object.public_send(@method_sym, **ruby_kwargs)
    else
      obj.object.public_send(@method_sym)
    end
  else
    raise <<-ERR
  Failed to implement #{@owner.graphql_name}.#{@name}, tried:

  - `#{obj.class}##{@method_sym}`, which did not exist
  - `#{obj.object.class}##{@method_sym}`, which did not exist
  - Looking up hash key `#{@method_sym.inspect}` or `#{@method_str.inspect}` on `#{obj.object}`, but it wasn't a Hash

  To implement this field, define one of the methods above (and check for typos)
  ERR
  end
end

#resolver ⇒ Class? Also known as: mutation

Returns The Resolver this field was derived from, if there is one

Returns:

  • (Class, nil) —

    The Resolver this field was derived from, if there is one



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# File 'lib/graphql/schema/field.rb', line 27

def resolver
  @resolver_class
end

#to_graphql ⇒ GraphQL::Field

Returns:



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# File 'lib/graphql/schema/field.rb', line 186

def to_graphql
  # this field was previously defined and passed here, so delegate to it
  if @field_instance
    return @field_instance.to_graphql
  end


  field_defn = if @field
    @field.dup
  elsif @function
    GraphQL::Function.build_field(@function)
  else
    GraphQL::Field.new
  end

  field_defn.name = @name
  if @return_type_expr
    field_defn.type = -> { type }
  end

  if @connection.nil?
    # Provide default based on type name
    return_type_name = if @field || @function
      Member::BuildType.to_type_name(field_defn.type)
    elsif @return_type_expr
      Member::BuildType.to_type_name(@return_type_expr)
    else
      raise "No connection info possible"
    end
    @connection = return_type_name.end_with?("Connection")
  end

  if @description
    field_defn.description = @description
  end

  if @deprecation_reason
    field_defn.deprecation_reason = @deprecation_reason
  end

  if @resolver_class
    if @resolver_class < GraphQL::Schema::Mutation
      field_defn.mutation = @resolver_class
    end
    field_defn.metadata[:resolver] = @resolver_class
  end

  field_defn.resolve = self.method(:resolve_field)
  field_defn.connection = @connection
  field_defn.connection_max_page_size = @max_page_size
  field_defn.introspection = @introspection
  field_defn.complexity = @complexity
  field_defn.subscription_scope = @subscription_scope

  # apply this first, so it can be overriden below
  if @connection
    # TODO: this could be a bit weird, because these fields won't be present
    # after initialization, only in the `to_graphql` response.
    # This calculation _could_ be moved up if need be.
    argument :after, "String", "Returns the elements in the list that come after the specified global ID.", required: false
    argument :before, "String", "Returns the elements in the list that come before the specified global ID.", required: false
    argument :first, "Int", "Returns the first _n_ elements from the list.", required: false
    argument :last, "Int", "Returns the last _n_ elements from the list.", required: false
  end

  arguments.each do |name, defn|
    arg_graphql = defn.to_graphql
    field_defn.arguments[arg_graphql.name] = arg_graphql
  end

  # Support a passed-in proc, one way or another
  @resolve_proc = if @resolve
    @resolve
  elsif @function
    @function
  elsif @field
    @field.resolve_proc
  end

  # Ok, `self` isn't a class, but this is for consistency with the classes
  field_defn.metadata[:type_class] = self

  field_defn
end

#type ⇒ Object 



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# File 'lib/graphql/schema/field.rb', line 271

def type
  @type ||= Member::BuildType.parse_type(@return_type_expr, null: @return_type_null)
rescue
  raise ArgumentError, "Failed to build return type for #{@owner.graphql_name}.#{name} from #{@return_type_expr.inspect}: #{$!.message}", $!.backtrace
end