Class: GraphQL::Execution::Lookahead
- Inherits:
-
Object
- Object
- GraphQL::Execution::Lookahead
- Defined in:
- lib/graphql/execution/lookahead.rb
Overview
Lookahead creates a uniform interface to inspect the forthcoming selections.
It assumes that the AST it’s working with is valid. (So, it’s safe to use during execution, but if you’re using it directly, be sure to validate first.)
A field may get access to its lookahead by adding extras: [:lookahead]
to its configuration.
Direct Known Subclasses
Defined Under Namespace
Modules: ArgumentHelpers, FieldHelpers Classes: NullLookahead
Constant Summary collapse
- NULL_LOOKAHEAD =
A singleton, so that misses don’t come with overhead.
NullLookahead.new
Instance Attribute Summary collapse
-
#ast_nodes ⇒ Array<GraphQL::Language::Nodes::Field>
readonly
-
#field ⇒ GraphQL::Schema::Field
readonly
-
#owner_type ⇒ GraphQL::Schema::Object, ...
readonly
Instance Method Summary collapse
-
#arguments ⇒ Hash<Symbol, Object>
-
#initialize(query:, ast_nodes:, field: nil, root_type: nil, owner_type: nil) ⇒ Lookahead
constructor
A new instance of Lookahead.
-
#inspect ⇒ Object
-
#name ⇒ Symbol
The method name of the field.
-
#selected? ⇒ Boolean
True if this lookahead represents a field that was requested.
-
#selection(field_name, selected_type: @selected_type, arguments: nil) ⇒ GraphQL::Execution::Lookahead
Like #selects?, but can be used for chaining.
-
#selections(arguments: nil) ⇒ Array<GraphQL::Execution::Lookahead>
Like #selection, but for all nodes.
-
#selects?(field_name, arguments: nil) ⇒ Boolean
True if this node has a selection on
field_name
.
Constructor Details
#initialize(query:, ast_nodes:, field: nil, root_type: nil, owner_type: nil) ⇒ Lookahead
Returns a new instance of Lookahead
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# File 'lib/graphql/execution/lookahead.rb', line 34 def initialize(query:, ast_nodes:, field: nil, root_type: nil, owner_type: nil) @ast_nodes = ast_nodes.freeze @field = field @root_type = root_type @query = query @selected_type = @field ? @field.type.unwrap : root_type @owner_type = owner_type end |
Instance Attribute Details
#ast_nodes ⇒ Array<GraphQL::Language::Nodes::Field> (readonly)
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# File 'lib/graphql/execution/lookahead.rb', line 44 def ast_nodes @ast_nodes end |
#field ⇒ GraphQL::Schema::Field (readonly)
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# File 'lib/graphql/execution/lookahead.rb', line 47 def field @field end |
#owner_type ⇒ GraphQL::Schema::Object, ... (readonly)
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# File 'lib/graphql/execution/lookahead.rb', line 50 def owner_type @owner_type end |
Instance Method Details
#arguments ⇒ Hash<Symbol, Object>
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# File 'lib/graphql/execution/lookahead.rb', line 53 def arguments @arguments ||= @field && ArgumentHelpers.arguments(@query, nil, @field, ast_nodes.first) end |
#inspect ⇒ Object
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# File 'lib/graphql/execution/lookahead.rb', line 153 def inspect "#<GraphQL::Execution::Lookahead #{@field ? "@field=#{@field.path.inspect}": "@root_type=#{@root_type}"} @ast_nodes.size=#{@ast_nodes.size}>" end |
#name ⇒ Symbol
The method name of the field. It returns the method_sym of the Lookahead’s field.
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# File 'lib/graphql/execution/lookahead.rb', line 149 def name @field && @field.original_name end |
#selected? ⇒ Boolean
Returns True if this lookahead represents a field that was requested
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# File 'lib/graphql/execution/lookahead.rb', line 74 def selected? true end |
#selection(field_name, selected_type: @selected_type, arguments: nil) ⇒ GraphQL::Execution::Lookahead
Like #selects?, but can be used for chaining. It returns a null object (check with #selected?)
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# File 'lib/graphql/execution/lookahead.rb', line 81 def selection(field_name, selected_type: @selected_type, arguments: nil) next_field_name = normalize_name(field_name) next_field_defn = FieldHelpers.get_field(@query.schema, selected_type, next_field_name) if next_field_defn next_nodes = [] @ast_nodes.each do |ast_node| ast_node.selections.each do |selection| find_selected_nodes(selection, next_field_name, next_field_defn, arguments: arguments, matches: next_nodes) end end if next_nodes.any? Lookahead.new(query: @query, ast_nodes: next_nodes, field: next_field_defn, owner_type: selected_type) else NULL_LOOKAHEAD end else NULL_LOOKAHEAD end end |
#selections(arguments: nil) ⇒ Array<GraphQL::Execution::Lookahead>
Like #selection, but for all nodes. It returns a list of Lookaheads for all Selections
If arguments:
is provided, each provided key/value will be matched
against the arguments in each selection. This method will filter the selections
if any of the given arguments:
do not match the given selection.
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# File 'lib/graphql/execution/lookahead.rb', line 118 def selections(arguments: nil) subselections_by_type = {} subselections_on_type = subselections_by_type[@selected_type] = {} @ast_nodes.each do |node| find_selections(subselections_by_type, subselections_on_type, @selected_type, node.selections, arguments) end subselections = [] subselections_by_type.each do |type, ast_nodes_by_response_key| ast_nodes_by_response_key.each do |response_key, ast_nodes| field_defn = FieldHelpers.get_field(@query.schema, type, ast_nodes.first.name) lookahead = Lookahead.new(query: @query, ast_nodes: ast_nodes, field: field_defn, owner_type: type) subselections.push(lookahead) end end subselections end |
#selects?(field_name, arguments: nil) ⇒ Boolean
True if this node has a selection on field_name
.
If field_name
is a String, it is treated as a GraphQL-style (camelized)
field name and used verbatim. If field_name
is a Symbol, it is
treated as a Ruby-style (underscored) name and camelized before comparing.
If arguments:
is provided, each provided key/value will be matched
against the arguments in the next selection. This method will return false
if any of the given arguments:
are not present and matching in the next selection.
(But, the next selection may contain more than the given arguments.)
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# File 'lib/graphql/execution/lookahead.rb', line 69 def selects?(field_name, arguments: nil) selection(field_name, arguments: arguments).selected? end |