Module: GraphQL::InternalRepresentation::Rewrite

Includes:
Language
Included in:
StaticValidation::DefaultVisitor, StaticValidation::NoValidateVisitor
Defined in:
lib/graphql/internal_representation/rewrite.rb

Overview

While visiting an AST, build a normalized, flattened tree of Nodes.

No unions or interfaces are present in this tree, only object types.

Selections from the AST are attached to the object types they apply to.

Inline fragments and fragment spreads are preserved in InternalRepresentation::Node#ast_spreads, where they can be used to check for the presence of directives. This might not be sufficient for future directives, since the selections' grouping is lost.

The rewritten query tree serves as the basis for the FieldsWillMerge validation.

Constant Summary collapse

NO_DIRECTIVES =
[].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Language

serialize

Instance Attribute Details

#rewrite_documentObject (readonly)

Returns InternalRepresentation::Document.

Returns:

  • InternalRepresentation::Document


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# File 'lib/graphql/internal_representation/rewrite.rb', line 22

def rewrite_document
  @rewrite_document
end

Instance Method Details

#initializeObject


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# File 'lib/graphql/internal_representation/rewrite.rb', line 24

def initialize(*)
  super
  @query = context.query
  @rewrite_document = InternalRepresentation::Document.new
  # Hash<Nodes::FragmentSpread => Set<InternalRepresentation::Node>>
  # A record of fragment spreads and the irep nodes that used them
  @rewrite_spread_parents = Hash.new { |h, k| h[k] = Set.new }
  # Hash<Nodes::FragmentSpread => Scope>
  @rewrite_spread_scopes = {}
  # Array<Set<InternalRepresentation::Node>>
  # The current point of the irep_tree during visitation
  @rewrite_nodes_stack = []
  # Array<Scope>
  @rewrite_scopes_stack = []
  @rewrite_skip_nodes = Set.new

  # Resolve fragment spreads.
  # Fragment definitions got their own irep trees during visitation.
  # Those nodes are spliced in verbatim (not copied), but this is OK
  # because fragments are resolved from the "bottom up", each fragment
  # can be shared between its usages.
  context.on_dependency_resolve do |defn_ast_node, spread_ast_nodes, frag_ast_node|
    frag_name = frag_ast_node.name
    fragment_node = @rewrite_document.fragment_definitions[frag_name]

    if fragment_node
      spread_ast_nodes.each do |spread_ast_node|
        parent_nodes = @rewrite_spread_parents[spread_ast_node]
        parent_scope = @rewrite_spread_scopes[spread_ast_node]
        parent_nodes.each do |parent_node|
          parent_node.deep_merge_node(fragment_node, scope: parent_scope, merge_self: false)
        end
      end
    end
  end
end

#on_field(ast_node, ast_parent) ⇒ Object


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# File 'lib/graphql/internal_representation/rewrite.rb', line 120

def on_field(ast_node, ast_parent)
  if skip?(ast_node)
    @rewrite_skip_nodes.add(ast_node)
  end

  if @rewrite_skip_nodes.empty?
    node_name = ast_node.alias || ast_node.name
    parent_nodes = @rewrite_nodes_stack.last
    next_nodes = []

    field_defn = context.field_definition
    if field_defn.nil?
      # It's a non-existent field
      new_scope = nil
    else
      field_return_type = field_defn.type
      @rewrite_scopes_stack.last.each do |scope_type|
        parent_nodes.each do |parent_node|
          node = parent_node.scoped_children[scope_type][node_name] ||= Node.new(
            parent: parent_node,
            name: node_name,
            owner_type: scope_type,
            query: @query,
            return_type: field_return_type,
          )
          node.ast_nodes << ast_node
          node.definitions << field_defn
          next_nodes << node
        end
      end
      new_scope = Scope.new(@query, field_return_type.unwrap)
    end

    @rewrite_nodes_stack.push(next_nodes)
    @rewrite_scopes_stack.push(new_scope)
  end

  super

  if @rewrite_skip_nodes.empty?
    @rewrite_nodes_stack.pop
    @rewrite_scopes_stack.pop
  end

  if @rewrite_skip_nodes.include?(ast_node)
    @rewrite_skip_nodes.delete(ast_node)
  end
end

#on_fragment_definition(ast_node, parent) ⇒ Object


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# File 'lib/graphql/internal_representation/rewrite.rb', line 71

def on_fragment_definition(ast_node, parent)
  push_root_node(ast_node, @rewrite_document.fragment_definitions) { super }
end

#on_fragment_spread(ast_node, ast_parent) ⇒ Object


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# File 'lib/graphql/internal_representation/rewrite.rb', line 169

def on_fragment_spread(ast_node, ast_parent)
  if @rewrite_skip_nodes.empty? && !skip?(ast_node)
    # Register the irep nodes that depend on this AST node:
    @rewrite_spread_parents[ast_node].merge(@rewrite_nodes_stack.last)
    @rewrite_spread_scopes[ast_node] = @rewrite_scopes_stack.last
  end
  super
end

#on_inline_fragment(node, parent) ⇒ Object


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# File 'lib/graphql/internal_representation/rewrite.rb', line 97

def on_inline_fragment(node, parent)
  # Inline fragments provide two things to the rewritten tree:
  # - They _may_ narrow the scope by their type condition
  # - They _may_ apply their directives to their children
  if skip?(node)
    @rewrite_skip_nodes.add(node)
  end

  if @rewrite_skip_nodes.empty?
    @rewrite_scopes_stack.push(@rewrite_scopes_stack.last.enter(context.type_definition))
  end

  super

  if @rewrite_skip_nodes.empty?
    @rewrite_scopes_stack.pop
  end

  if @rewrite_skip_nodes.include?(node)
    @rewrite_skip_nodes.delete(node)
  end
end

#on_operation_definition(ast_node, parent) ⇒ Object


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# File 'lib/graphql/internal_representation/rewrite.rb', line 67

def on_operation_definition(ast_node, parent)
  push_root_node(ast_node, @rewrite_document.operation_definitions) { super }
end

#operationsHash<String, Node>

Returns Roots of this query.

Returns:

  • (Hash<String, Node>)

    Roots of this query


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# File 'lib/graphql/internal_representation/rewrite.rb', line 62

def operations
  warn "#{self.class}#operations is deprecated; use `document.operation_definitions` instead"
  @document.operation_definitions
end

#push_root_node(ast_node, definitions) ⇒ Object


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# File 'lib/graphql/internal_representation/rewrite.rb', line 75

def push_root_node(ast_node, definitions)
  # Either QueryType or the fragment type condition
  owner_type = context.type_definition
  defn_name = ast_node.name

  node = Node.new(
    parent: nil,
    name: defn_name,
    owner_type: owner_type,
    query: @query,
    ast_nodes: [ast_node],
    return_type: owner_type,
  )

  definitions[defn_name] = node
  @rewrite_scopes_stack.push(Scope.new(@query, owner_type))
  @rewrite_nodes_stack.push([node])
  yield
  @rewrite_nodes_stack.pop
  @rewrite_scopes_stack.pop
end

#skip?(ast_node) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/graphql/internal_representation/rewrite.rb', line 178

def skip?(ast_node)
  dir = ast_node.directives
  dir.any? && !GraphQL::Execution::DirectiveChecks.include?(dir, @query)
end