Class: Tina4::GraphQLExecutor

Inherits:
Object
  • Object
show all
Defined in:
lib/tina4/graphql.rb

Overview

─── Executor ─────────────────────────────────────────────────────────

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(schema, max_depth: 50) ⇒ GraphQLExecutor

Returns a new instance of GraphQLExecutor.



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# File 'lib/tina4/graphql.rb', line 603

def initialize(schema, max_depth: 50)
  @schema = schema
  @max_depth = max_depth
end

Instance Attribute Details

#max_depth ⇒ Object

max_depth bounds selection-set nesting (DoS / stack-overflow guard). Threaded down from the owning GraphQL instance; <= 0 disables the guard.



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# File 'lib/tina4/graphql.rb', line 601

def max_depth
  @max_depth
end

Instance Method Details

#execute(document, variables: {}, context: {}, operation_name: nil) ⇒ Object

Raises:



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# File 'lib/tina4/graphql.rb', line 608

def execute(document, variables: {}, context: {}, operation_name: nil)
  # Collect fragments
  fragments = {}
  operations = []

  document[:definitions].each do |defn|
    case defn[:kind]
    when :fragment
      fragments[defn[:name]] = defn
    when :operation
      operations << defn
    end
  end

  # Pick the operation
  operation = if operation_name
                operations.find { |op| op[:name] == operation_name }
              elsif operations.length == 1
                operations.first
              else
                raise GraphQLError, "Must provide operation name when multiple operations exist"
              end

  raise GraphQLError, "Unknown operation: #{operation_name}" unless operation

  # Resolve variables
  resolved_vars = resolve_variables(operation[:variables], variables)

  # Choose root fields
  root_fields = case operation[:operation]
                when :query    then @schema.queries
                when :mutation then @schema.mutations
                else raise GraphQLError, "Unsupported operation: #{operation[:operation]}"
                end

  # Execute selection set
  data = {}
  errors = []

  # Top-level selections start at depth 1. Depth is incremented on every
  # recursive entry (sub-selections, fragment spreads, inline fragments) so
  # an over-deep query OR a circular fragment is caught before the
  # interpreter stack overflows.
  operation[:selection_set].each do |selection|
    resolve_selection(selection, root_fields, nil, resolved_vars, context, fragments, data, errors, 1)
  end

  result = { "data" => data }
  result["errors"] = errors unless errors.empty?
  result
end