62 lines
1.8 KiB
Ruby
62 lines
1.8 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
# Recursive queries, with relatively low effort, can quickly spiral out of control exponentially
|
|
# and may not be picked up by depth and complexity alone.
|
|
module Gitlab
|
|
module Graphql
|
|
module QueryAnalyzers
|
|
class RecursionAnalyzer
|
|
IGNORED_FIELDS = %w(node edges nodes ofType).freeze
|
|
RECURSION_THRESHOLD = 2
|
|
|
|
def initial_value(query)
|
|
{
|
|
recurring_fields: {}
|
|
}
|
|
end
|
|
|
|
def call(memo, visit_type, irep_node)
|
|
return memo if skip_node?(irep_node)
|
|
|
|
node_name = irep_node.ast_node.name
|
|
times_encountered = memo[node_name] || 0
|
|
|
|
if visit_type == :enter
|
|
times_encountered += 1
|
|
memo[:recurring_fields][node_name] = times_encountered if recursion_too_deep?(node_name, times_encountered)
|
|
else
|
|
times_encountered -= 1
|
|
end
|
|
|
|
memo[node_name] = times_encountered
|
|
memo
|
|
end
|
|
|
|
def final_value(memo)
|
|
recurring_fields = memo[:recurring_fields]
|
|
recurring_fields = recurring_fields.select { |k, v| recursion_too_deep?(k, v) }
|
|
if recurring_fields.any?
|
|
GraphQL::AnalysisError.new("Recursive query - too many of fields '#{recurring_fields}' detected in single branch of the query")
|
|
end
|
|
end
|
|
|
|
private
|
|
|
|
def recursion_too_deep?(node_name, times_encountered)
|
|
return if IGNORED_FIELDS.include?(node_name)
|
|
|
|
times_encountered > recursion_threshold
|
|
end
|
|
|
|
def skip_node?(irep_node)
|
|
ast_node = irep_node.ast_node
|
|
!ast_node.is_a?(GraphQL::Language::Nodes::Field) || ast_node.selections.empty?
|
|
end
|
|
|
|
def recursion_threshold
|
|
RECURSION_THRESHOLD
|
|
end
|
|
end
|
|
end
|
|
end
|
|
end
|