blob: eaac75c70465d22ab7907171a12035adb00879e4 [file] [log] [blame]
// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
library shelf.handlers.logger;
import 'package:stack_trace/stack_trace.dart';
import '../hijack_exception.dart';
import '../middleware.dart';
import '../util.dart';
/// Middleware which prints the time of the request, the elapsed time for the
/// inner handlers, the response's status code and the request URI.
/// [logger] takes two paramaters.
/// `msg` includes the request time, duration, request method, and requested
/// path.
/// For successful requests, `msg` also includes the status code.
/// When an error is thrown, `isError` is true and `msg` contains the error
/// description and stack trace.
Middleware logRequests({void logger(String msg, bool isError)}) =>
(innerHandler) {
if (logger == null) logger = _defaultLogger;
return (request) {
var startTime = new;
var watch = new Stopwatch()..start();
return syncFuture(() => innerHandler(request)).then((response) {
var msg = _getMessage(startTime, response.statusCode,
request.requestedUri, request.method, watch.elapsed);
logger(msg, false);
return response;
}, onError: (error, stackTrace) {
if (error is HijackException) throw error;
var msg = _getErrorMessage(startTime, request.requestedUri,
request.method, watch.elapsed, error, stackTrace);
logger(msg, true);
throw error;
String _getMessage(DateTime requestTime, int statusCode, Uri requestedUri,
String method, Duration elapsedTime) {
return '${requestTime}\t$elapsedTime\t$method\t[${statusCode}]\t'
String _getErrorMessage(DateTime requestTime, Uri requestedUri, String method,
Duration elapsedTime, Object error, StackTrace stack) {
var chain = new Chain.current();
if (stack != null) {
chain = new Chain.forTrace(stack)
.foldFrames((frame) => frame.isCore || frame.package == 'shelf').terse;
var msg = '${requestTime}\t$elapsedTime\t$method\t${requestedUri.path}'
if (chain == null) return msg;
return '$msg\n$chain';
void _defaultLogger(String msg, bool isError) {
if (isError) {
print('[ERROR] $msg');
} else {