class GraphQL::Analysis::QueryDepth

A query reducer for measuring the depth of a given query.

@example Logging the depth of a query

Schema.query_analyzers << GraphQL::Analysis::QueryDepth.new { |query, depth|  puts "GraphQL query depth: #{depth}" }
Schema.execute(query_str)
# GraphQL query depth: 8

Public Class Methods

new(&block) click to toggle source
# File lib/graphql/analysis/query_depth.rb, line 11
def initialize(&block)
  @depth_handler = block
end

Public Instance Methods

call(memo, visit_type, irep_node) click to toggle source
# File lib/graphql/analysis/query_depth.rb, line 24
def call(memo, visit_type, irep_node)
  if irep_node.ast_node.is_a?(GraphQL::Language::Nodes::Field)
    # Don't validate introspection fields or skipped nodes
    not_validated_node = GraphQL::Schema::DYNAMIC_FIELDS.include?(irep_node.definition_name)
    if visit_type == :enter
      if not_validated_node
        memo[:skip_depth] += 1
      elsif memo[:skip_depth] > 0
        # we're inside an introspection query or skipped node
      else
        memo[:current_depth] += 1
      end
    else
      if not_validated_node
        memo[:skip_depth] -= 1
      else
        if memo[:max_depth] < memo[:current_depth]
          memo[:max_depth] = memo[:current_depth]
        end
        memo[:current_depth] -= 1
      end
    end
  end
  memo
end
final_value(memo) click to toggle source
# File lib/graphql/analysis/query_depth.rb, line 50
def final_value(memo)
  @depth_handler.call(memo[:query], memo[:max_depth])
end
initial_value(query) click to toggle source
# File lib/graphql/analysis/query_depth.rb, line 15
def initial_value(query)
  {
    max_depth: 0,
    current_depth: 0,
    skip_depth: 0,
    query: query,
  }
end