strong-error-handler/lib/handler.js

78 lines
2.1 KiB
JavaScript

// Copyright IBM Corp. 2016,2018. All Rights Reserved.
// Node module: strong-error-handler
// This file is licensed under the MIT License.
// License text available at https://opensource.org/licenses/MIT
'use strict';
const path = require('path');
const SG = require('strong-globalize');
SG.SetRootDir(path.resolve(__dirname, '..'));
const buildResponseData = require('./data-builder');
const debug = require('debug')('strong-error-handler');
const logToConsole = require('./logger');
const negotiateContentProducer = require('./content-negotiation');
function noop() {
}
/**
* Create a middleware error handler function.
*
* @param {Object} options
* @returns {Function}
*/
function createStrongErrorHandler(options) {
options = options || {};
debug('Initializing with options %j', options);
// Log all errors via console.error (enabled by default)
const logError = options.log !== false ? logToConsole : noop;
return function strongErrorHandler(err, req, res, next) {
logError(req, err);
writeErrorToResponse(err, req, res, options);
};
}
/**
* Writes thrown error to response
*
* @param {Error} err
* @param {Express.Request} req
* @param {Express.Response} res
* @param {Object} options
*/
function writeErrorToResponse(err, req, res, options) {
debug('Handling %s', err.stack || err);
options = options || {};
if (res.headersSent) {
debug('Response was already sent, closing the underlying connection');
return req.socket.destroy();
}
// this will alter the err object, to handle when res.statusCode is an error
if (!err.status && !err.statusCode && res.statusCode >= 400)
err.statusCode = res.statusCode;
const data = buildResponseData(err, options);
debug('Response status %s data %j', data.statusCode, data);
res.setHeader('X-Content-Type-Options', 'nosniff');
res.statusCode = data.statusCode;
const sendResponse = negotiateContentProducer(req, warn, options);
sendResponse(res, data, options);
function warn(msg) {
res.header('X-Warning', msg);
debug(msg);
}
}
exports = module.exports = createStrongErrorHandler;
exports.writeErrorToResponse = writeErrorToResponse;