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/*!
* finalhandler
* Copyright(c) 2014-2015 Douglas Christopher Wilson
* MIT Licensed
*/
'use strict'
/**
* Module dependencies.
* @private
*/
var debug = require('debug')('finalhandler')
var escapeHtml = require('escape-html')
var onFinished = require('on-finished')
var statuses = require('statuses')
var unpipe = require('unpipe')
/**
* Module variables.
* @private
*/
/* istanbul ignore next */
var defer = typeof setImmediate === 'function'
? setImmediate
: function (fn) { process.nextTick(fn.bind.apply(fn, arguments)) }
var isFinished = onFinished.isFinished
/**
* Module exports.
* @public
*/
module.exports = finalhandler
/**
* Create a function to handle the final response.
*
* @param {Request} req
* @param {Response} res
* @param {Object} [options]
* @return {Function}
* @public
*/
function finalhandler (req, res, options) {
var opts = options || {}
// get environment
var env = opts.env || process.env.NODE_ENV || 'development'
// get error callback
var onerror = opts.onerror
return function (err) {
var headers = Object.create(null)
var status
// ignore 404 on in-flight response
if (!err && res._header) {
debug('cannot 404 after headers sent')
return
}
// unhandled error
if (err) {
// respect status code from error
status = getErrorStatusCode(err) || res.statusCode
// default status code to 500 if outside valid range
if (typeof status !== 'number' || status < 400 || status > 599) {
status = 500
}
// respect err.headers
if (err.headers && (err.status === status || err.statusCode === status)) {
var keys = Object.keys(err.headers)
for (var i = 0; i < keys.length; i++) {
var key = keys[i]
headers[key] = err.headers[key]
}
}
// production gets a basic error message
var msg = env === 'production'
? statuses[status]
: err.stack || err.toString()
msg = escapeHtml(msg)
.replace(/\n/g, '<br>')
.replace(/\x20{2}/g, ' ') + '\n'
} else {
status = 404
msg = 'Cannot ' + escapeHtml(req.method) + ' ' + escapeHtml(req.originalUrl || req.url) + '\n'
}
debug('default %s', status)
// schedule onerror callback
if (err && onerror) {
defer(onerror, err, req, res)
}
// cannot actually respond
if (res._header) {
debug('cannot %d after headers sent', status)
req.socket.destroy()
return
}
// send response
send(req, res, status, headers, msg)
}
}
/**
* Get status code from Error object.
*
* @param {Error} err
* @return {number}
* @private
*/
function getErrorStatusCode (err) {
// check err.status
if (typeof err.status === 'number' && err.status >= 400 && err.status < 600) {
return err.status
}
// check err.statusCode
if (typeof err.statusCode === 'number' && err.statusCode >= 400 && err.statusCode < 600) {
return err.statusCode
}
return undefined
}
/**
* Send response.
*
* @param {IncomingMessage} req
* @param {OutgoingMessage} res
* @param {number} status
* @param {object} headers
* @param {string} body
* @private
*/
function send (req, res, status, headers, body) {
function write () {
// response status
res.statusCode = status
res.statusMessage = statuses[status]
// response headers
var keys = Object.keys(headers)
for (var i = 0; i < keys.length; i++) {
var key = keys[i]
res.setHeader(key, headers[key])
}
// security header for content sniffing
res.setHeader('X-Content-Type-Options', 'nosniff')
// standard headers
res.setHeader('Content-Type', 'text/html; charset=utf-8')
res.setHeader('Content-Length', Buffer.byteLength(body, 'utf8'))
if (req.method === 'HEAD') {
res.end()
return
}
res.end(body, 'utf8')
}
if (isFinished(req)) {
write()
return
}
// unpipe everything from the request
unpipe(req)
// flush the request
onFinished(req, write)
req.resume()
}
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