Class: RackGraphql::Middleware

Inherits:
Object
  • Object
show all
Defined in:
lib/rack_graphql/middleware.rb

Constant Summary collapse

DEFAULT_STATUS_CODE = 
200
DEFAULT_ERROR_STATUS_CODE = 
500
STATUS_CODE_HEADER_NAME = 
'X-Http-Status-Code'.freeze
SUBSCRIPTION_ID_HEADER_NAME = 
'X-Subscription-ID'.freeze
NULL_BYTE = 
'\u0000'.freeze

Instance Method Summary collapse

Constructor Details

#initialize(schema:, app_name: nil, context_handler: nil, logger: nil, log_exception_backtrace: RackGraphql.log_exception_backtrace, re_raise_exceptions: false, error_status_code_map: {}, request_epilogue: -> {}) ⇒ Middleware

Returns a new instance of Middleware.



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# File 'lib/rack_graphql/middleware.rb', line 9

def initialize(
  schema:,
  app_name: nil,
  context_handler: nil,
  logger: nil,
  log_exception_backtrace: RackGraphql.log_exception_backtrace,
  re_raise_exceptions: false,
  error_status_code_map: {},
  request_epilogue: -> {}
)

  @schema = schema
  @app_name = app_name
  @context_handler = context_handler || ->(_) {}
  @logger = logger
  @log_exception_backtrace = log_exception_backtrace
  @re_raise_exceptions = re_raise_exceptions
  @error_status_code_map = error_status_code_map
  @request_epilogue = request_epilogue || -> {}
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/rack_graphql/middleware.rb', line 30

def call(env)
  return [406, {}, []] unless post_request?(env)

  params = post_data(env)

  return [400, {}, []] unless params.is_a?(Hash)

  variables = ensure_hash(params['variables'])
  operation_name = params['operationName']
  context = context_handler.call(env)

  log("Executing with params: #{params.inspect}, operationName: #{operation_name}, variables: #{variables.inspect}")
  result = execute(params:, operation_name:, variables:, context:)
  status_code = response_status(result)

  [
    status_code,
    response_headers(result, status_code:),
    [response_body(result)]
  ]
rescue AmbiguousParamError => e
  exception_string = dump_exception(e)
  log(exception_string)
  env[Rack::RACK_ERRORS].puts(exception_string)
  env[Rack::RACK_ERRORS].flush
  [
    400,
    { 'Content-Type' => 'application/json', STATUS_CODE_HEADER_NAME => 400 },
    [JSON.dump({})]
  ]
rescue StandardError, LoadError, SyntaxError => e
  # To respect the graphql spec, all errors need to be returned as json.
  # By default exceptions are not re-raised,
  # so they cannot be caught by error tracking rack middlewares.
  # You can change this behavior via `re_raise_exceptions` argument.
  exception_string = dump_exception(e)
  log(exception_string)

  raise e if re_raise_exceptions

  env[Rack::RACK_ERRORS].puts(exception_string)
  env[Rack::RACK_ERRORS].flush

  status_code = error_status_code_map[e.class] || DEFAULT_ERROR_STATUS_CODE
  [
    status_code,
    { 'Content-Type' => 'application/json', STATUS_CODE_HEADER_NAME => status_code },
    [JSON.dump('errors' => [exception_hash(e)])]
  ]
ensure
  request_epilogue.call
end