Class: GraphQL::Stitching::Executor::TypeResolverSource

Inherits:
Dataloader::Source
  • Object
show all
Defined in:
lib/graphql/stitching/executor/type_resolver_source.rb

Instance Method Summary collapse

Constructor Details

#initialize(executor, location) ⇒ TypeResolverSource

Returns a new instance of TypeResolverSource.



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# File 'lib/graphql/stitching/executor/type_resolver_source.rb', line 6

def initialize(executor, location)
  @executor = executor
  @location = location
  @variables = {}
end

Instance Method Details

#build_document(origin_sets_by_operation, operation_name = nil, operation_directives = nil) ⇒ Object

Builds batched resolver queries "query MyOperation_2_3($var:VarType, $_0_key:[ID!]!, $_1_0_key:ID!, $_1_1_key:ID!, $_1_2_key:ID!) { _0_result: list(keys: $_0_key) { resolverSelections... } _1_0_result: item(key: $_1_0_key) { resolverSelections... } _1_1_result: item(key: $_1_1_key) { resolverSelections... } _1_2_result: item(key: $_1_2_key) { resolverSelections... } }"



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# File 'lib/graphql/stitching/executor/type_resolver_source.rb', line 52

def build_document(origin_sets_by_operation, operation_name = nil, operation_directives = nil)
  variable_defs = {}
  fields_buffer = String.new

  origin_sets_by_operation.each_with_index do |(op, origin_set), batch_index|
    variable_defs.merge!(op.variables)
    resolver = @executor.request.supergraph.resolvers_by_version[op.resolver]
    fields_buffer << " " unless batch_index.zero?

    if resolver.list?
      fields_buffer << "_" << batch_index.to_s << "_result: " << resolver.field << "("

      resolver.arguments.each_with_index do |arg, i|
        fields_buffer << "," unless i.zero?
        if arg.key?
          variable_name = "_#{batch_index}_key_#{i}".freeze
          @variables[variable_name] = origin_set.map { arg.build(_1) }
          variable_defs[variable_name] = arg.to_type_signature
          fields_buffer << arg.name << ":$" << variable_name
        else
          fields_buffer << arg.name << ":" << arg.value.print
        end
      end

      fields_buffer << ") " << op.selections
    else
      origin_set.each_with_index do |origin_obj, index|
        fields_buffer << " " unless index.zero?
        fields_buffer << "_" << batch_index.to_s << "_" << index.to_s << "_result: " << resolver.field << "("

        resolver.arguments.each_with_index do |arg, i|
          fields_buffer << "," unless i.zero?
          if arg.key?
            variable_name = "_#{batch_index}_#{index}_key_#{i}".freeze
            @variables[variable_name] = arg.build(origin_obj)
            variable_defs[variable_name] = arg.to_type_signature
            fields_buffer << arg.name << ":$" << variable_name
          else
            fields_buffer << arg.name << ":" << arg.value.print
          end
        end

        fields_buffer << ") " << op.selections
      end
    end
  end

  doc_buffer = String.new(QUERY_OP) # << resolver fulfillment always uses query

  if operation_name
    doc_buffer << " " << operation_name
    origin_sets_by_operation.each_key do |op|
      doc_buffer << "_" << op.step.to_s
    end
  end

  unless variable_defs.empty?
    doc_buffer << "("
    variable_defs.each_with_index do |(k, v), i|
      doc_buffer << "," unless i.zero?
      doc_buffer << "$" << k << ":" << v
    end
    doc_buffer << ")"
  end

  if operation_directives
    doc_buffer << " " << operation_directives << " "
  end

  doc_buffer << "{ " << fields_buffer << " }"

  return doc_buffer, variable_defs.keys.tap do |names|
    names.reject! { @variables.key?(_1) }
  end
end

#extract_errors!(origin_sets_by_operation, errors) ⇒ Object

https://spec.graphql.org/June2018/#sec-Errors



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# File 'lib/graphql/stitching/executor/type_resolver_source.rb', line 148

def extract_errors!(origin_sets_by_operation, errors)
  ops = origin_sets_by_operation.keys
  origin_sets = origin_sets_by_operation.values
  pathed_errors_by_op_index_and_object_id = Hash.new { |h, k| h[k] = {} }

  errors_result = errors.each_with_object([]) do |err, memo|
    err.delete("locations")
    path = err["path"]

    if path && path.length > 0
      result_alias = /^_(\d+)(?:_(\d+))?_result$/.match(path.first.to_s)

      if result_alias
        path = err["path"] = path[1..-1]

        origin_obj = if result_alias[2]
          origin_sets.dig(result_alias[1].to_i, result_alias[2].to_i)
        elsif path[0].is_a?(Integer) || /\d+/.match?(path[0].to_s)
          origin_sets.dig(result_alias[1].to_i, path.shift.to_i)
        end

        if origin_obj
          pathed_errors_by_op_index = pathed_errors_by_op_index_and_object_id[result_alias[1].to_i]
          by_object_id = pathed_errors_by_op_index[origin_obj.object_id] ||= []
          by_object_id << err
          next
        end
      end
    end

    memo << err
  end

  unless pathed_errors_by_op_index_and_object_id.empty?
    pathed_errors_by_op_index_and_object_id.each do |op_index, pathed_errors_by_object_id|
      repath_errors!(pathed_errors_by_object_id, ops[op_index].path)
      errors_result.push(*pathed_errors_by_object_id.each_value)
    end
  end

  errors_result.tap(&:flatten!)
end

#fetch(ops) ⇒ Object 



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# File 'lib/graphql/stitching/executor/type_resolver_source.rb', line 12

def fetch(ops)
  origin_sets_by_operation = ops.each_with_object({}.compare_by_identity) do |op, memo|
    origin_set = op.path.reduce([@executor.data]) do |set, path_segment|
      set.flat_map { |obj| obj && obj[path_segment] }.tap(&:compact!)
    end

    if op.if_type
      # operations planned around unused fragment conditions should not trigger requests
      origin_set.select! { _1[TypeResolver::TYPENAME_EXPORT_NODE.alias] == op.if_type }
    end

    memo[op] = origin_set unless origin_set.empty?
  end

  unless origin_sets_by_operation.empty?
    query_document, variable_names = build_document(
      origin_sets_by_operation,
      @executor.request.operation_name,
      @executor.request.operation_directives,
    )
    variables = @variables.merge!(@executor.request.variables.slice(*variable_names))
    raw_result = @executor.request.supergraph.execute_at_location(@location, query_document, variables, @executor.request)
    @executor.query_count += 1

    merge_results!(origin_sets_by_operation, raw_result.dig("data"))

    errors = raw_result.dig("errors")
    @executor.errors.concat(extract_errors!(origin_sets_by_operation, errors)) if errors&.any?
  end

  ops.map { origin_sets_by_operation[_1] ? _1.step : nil }
end

#merge_results!(origin_sets_by_operation, raw_result) ⇒ Object 



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# File 'lib/graphql/stitching/executor/type_resolver_source.rb', line 128

def merge_results!(origin_sets_by_operation, raw_result)
  return unless raw_result

  origin_sets_by_operation.each_with_index do |(op, origin_set), batch_index|
    results = if @executor.request.supergraph.resolvers_by_version[op.resolver].list?
      raw_result["_#{batch_index}_result"]
    else
      origin_set.map.with_index { |_, index| raw_result["_#{batch_index}_#{index}_result"] }
    end

    next if results.nil? || results.empty?

    origin_set.each_with_index do |origin_obj, index|
      result = results[index]
      origin_obj.merge!(result) if result
    end
  end
end