lib/grape/middleware/error.rb
# frozen_string_literal: true
module Grape
module Middleware
class Error < Base
def default_options
{
default_status: 500, # default status returned on error
default_message: '',
format: :txt,
helpers: nil,
formatters: {},
error_formatters: {},
rescue_all: false, # true to rescue all exceptions
rescue_grape_exceptions: false,
rescue_subclasses: true, # rescue subclasses of exceptions listed
rescue_options: {
backtrace: false, # true to display backtrace, true to let Grape handle Grape::Exceptions
original_exception: false # true to display exception
},
rescue_handlers: {}, # rescue handler blocks
base_only_rescue_handlers: {}, # rescue handler blocks rescuing only the base class
all_rescue_handler: nil # rescue handler block to rescue from all exceptions
}
end
def initialize(app, *options)
super
self.class.send(:include, @options[:helpers]) if @options[:helpers]
end
def call!(env)
@env = env
error_response(catch(:error) { return @app.call(@env) })
rescue Exception => e # rubocop:disable Lint/RescueException
run_rescue_handler(find_handler(e.class), e, @env[Grape::Env::API_ENDPOINT])
end
private
def rack_response(status, headers, message)
message = Rack::Utils.escape_html(message) if headers[Rack::CONTENT_TYPE] == TEXT_HTML
Rack::Response.new(Array.wrap(message), Rack::Utils.status_code(status), Grape::Util::Header.new.merge(headers))
end
def format_message(message, backtrace, original_exception = nil)
format = env[Grape::Env::API_FORMAT] || options[:format]
formatter = Grape::ErrorFormatter.formatter_for(format, **options)
return formatter.call(message, backtrace, options, env, original_exception) if formatter
throw :error,
status: 406,
message: "The requested format '#{format}' is not supported.",
backtrace: backtrace,
original_exception: original_exception
end
def find_handler(klass)
rescue_handler_for_base_only_class(klass) ||
rescue_handler_for_class_or_its_ancestor(klass) ||
rescue_handler_for_grape_exception(klass) ||
rescue_handler_for_any_class(klass) ||
raise
end
def error_response(error = {})
status = error[:status] || options[:default_status]
message = error[:message] || options[:default_message]
headers = { Rack::CONTENT_TYPE => content_type }.tap do |h|
h.merge!(error[:headers]) if error[:headers].is_a?(Hash)
end
backtrace = error[:backtrace] || error[:original_exception]&.backtrace || []
original_exception = error.is_a?(Exception) ? error : error[:original_exception] || nil
rack_response(status, headers, format_message(message, backtrace, original_exception))
end
def default_rescue_handler(e)
error_response(message: e.message, backtrace: e.backtrace, original_exception: e)
end
def rescue_handler_for_base_only_class(klass)
error, handler = options[:base_only_rescue_handlers].find { |err, _handler| klass == err }
return unless error
handler || method(:default_rescue_handler)
end
def rescue_handler_for_class_or_its_ancestor(klass)
error, handler = options[:rescue_handlers].find { |err, _handler| klass <= err }
return unless error
handler || method(:default_rescue_handler)
end
def rescue_handler_for_grape_exception(klass)
return unless klass <= Grape::Exceptions::Base
return method(:error_response) if klass == Grape::Exceptions::InvalidVersionHeader
return unless options[:rescue_grape_exceptions] || !options[:rescue_all]
options[:grape_exceptions_rescue_handler] || method(:error_response)
end
def rescue_handler_for_any_class(klass)
return unless klass <= StandardError
return unless options[:rescue_all] || options[:rescue_grape_exceptions]
options[:all_rescue_handler] || method(:default_rescue_handler)
end
def run_rescue_handler(handler, error, endpoint)
if handler.instance_of?(Symbol)
raise NoMethodError, "undefined method '#{handler}'" unless respond_to?(handler)
handler = public_method(handler)
end
response = catch(:error) do
handler.arity.zero? ? endpoint.instance_exec(&handler) : endpoint.instance_exec(error, &handler)
end
response = error!(response[:message], response[:status], response[:headers]) if error?(response)
if response.is_a?(Rack::Response)
response
else
run_rescue_handler(:default_rescue_handler, Grape::Exceptions::InvalidResponse.new, endpoint)
end
end
def error!(message, status = options[:default_status], headers = {}, backtrace = [], original_exception = nil)
rack_response(
status, headers.reverse_merge(Rack::CONTENT_TYPE => content_type),
format_message(message, backtrace, original_exception)
)
end
def error?(response)
response.is_a?(Hash) && response[:message] && response[:status] && response[:headers]
end
end
end
end