third_party/devtools/node_modules/finalhandler/index.js - cobalt - Git at Google

 /*!
  * finalhandler
  * Copyright(c) 2014-2017 Douglas Christopher Wilson
  * MIT Licensed
  */

 'use strict'

 /**
  * Module dependencies.
  * @private
  */

 var debug = require('debug')('finalhandler')
 var encodeUrl = require('encodeurl')
 var escapeHtml = require('escape-html')
 var onFinished = require('on-finished')
 var parseUrl = require('parseurl')
 var statuses = require('statuses')
 var unpipe = require('unpipe')

 /**
  * Module variables.
  * @private
  */

 var DOUBLE_SPACE_REGEXP = /\x20{2}/g
 var NEWLINE_REGEXP = /\n/g

 /* istanbul ignore next */
 var defer = typeof setImmediate === 'function'
   ? setImmediate
   : function (fn) { process.nextTick(fn.bind.apply(fn, arguments)) }
 var isFinished = onFinished.isFinished

 /**
  * Create a minimal HTML document.
  *
  * @param {string} message
  * @private
  */

 function createHtmlDocument (message) {
   var body = escapeHtml(message)
     .replace(NEWLINE_REGEXP, '<br>')
     .replace(DOUBLE_SPACE_REGEXP, ' &nbsp;')

   return '<!DOCTYPE html>\n' +
     '<html lang="en">\n' +
     '<head>\n' +
     '<meta charset="utf-8">\n' +
     '<title>Error</title>\n' +
     '</head>\n' +
     '<body>\n' +
     '<pre>' + body + '</pre>\n' +
     '</body>\n' +
     '</html>\n'
 }

 /**
  * 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
     var msg
     var status

     // ignore 404 on in-flight response
     if (!err && headersSent(res)) {
       debug('cannot 404 after headers sent')
       return
     }

     // unhandled error
     if (err) {
       // respect status code from error
       status = getErrorStatusCode(err)

       if (status === undefined) {
         // fallback to status code on response
         status = getResponseStatusCode(res)
       } else {
         // respect headers from error
         headers = getErrorHeaders(err)
       }

       // get error message
       msg = getErrorMessage(err, status, env)
     } else {
       // not found
       status = 404
       msg = 'Cannot ' + req.method + ' ' + encodeUrl(getResourceName(req))
     }

     debug('default %s', status)

     // schedule onerror callback
     if (err && onerror) {
       defer(onerror, err, req, res)
     }

     // cannot actually respond
     if (headersSent(res)) {
       debug('cannot %d after headers sent', status)
       req.socket.destroy()
       return
     }

     // send response
     send(req, res, status, headers, msg)
   }
 }

 /**
  * Get headers from Error object.
  *
  * @param {Error} err
  * @return {object}
  * @private
  */

 function getErrorHeaders (err) {
   if (!err.headers || typeof err.headers !== 'object') {
     return undefined
   }

   var headers = Object.create(null)
   var keys = Object.keys(err.headers)

   for (var i = 0; i < keys.length; i++) {
     var key = keys[i]
     headers[key] = err.headers[key]
   }

   return headers
 }

 /**
  * Get message from Error object, fallback to status message.
  *
  * @param {Error} err
  * @param {number} status
  * @param {string} env
  * @return {string}
  * @private
  */

 function getErrorMessage (err, status, env) {
   var msg

   if (env !== 'production') {
     // use err.stack, which typically includes err.message
     msg = err.stack

     // fallback to err.toString() when possible
     if (!msg && typeof err.toString === 'function') {
       msg = err.toString()
     }
   }

   return msg || statuses[status]
 }

 /**
  * 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
 }

 /**
  * Get resource name for the request.
  *
  * This is typically just the original pathname of the request
  * but will fallback to "resource" is that cannot be determined.
  *
  * @param {IncomingMessage} req
  * @return {string}
  * @private
  */

 function getResourceName (req) {
   try {
     return parseUrl.original(req).pathname
   } catch (e) {
     return 'resource'
   }
 }

 /**
  * Get status code from response.
  *
  * @param {OutgoingMessage} res
  * @return {number}
  * @private
  */

 function getResponseStatusCode (res) {
   var status = res.statusCode

   // default status code to 500 if outside valid range
   if (typeof status !== 'number' || status < 400 || status > 599) {
     status = 500
   }

   return status
 }

 /**
  * Determine if the response headers have been sent.
  *
  * @param {object} res
  * @returns {boolean}
  * @private
  */

 function headersSent (res) {
   return typeof res.headersSent !== 'boolean'
     ? Boolean(res._header)
     : res.headersSent
 }

 /**
  * Send response.
  *
  * @param {IncomingMessage} req
  * @param {OutgoingMessage} res
  * @param {number} status
  * @param {object} headers
  * @param {string} message
  * @private
  */

 function send (req, res, status, headers, message) {
   function write () {
     // response body
     var body = createHtmlDocument(message)

     // response status
     res.statusCode = status
     res.statusMessage = statuses[status]

     // response headers
     setHeaders(res, headers)

     // security headers
     res.setHeader('Content-Security-Policy', "default-src 'none'")
     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()
 }

 /**
  * Set response headers from an object.
  *
  * @param {OutgoingMessage} res
  * @param {object} headers
  * @private
  */

 function setHeaders (res, headers) {
   if (!headers) {
     return
   }

   var keys = Object.keys(headers)
   for (var i = 0; i < keys.length; i++) {
     var key = keys[i]
     res.setHeader(key, headers[key])
   }
 }
	/*!
	* finalhandler
	* Copyright(c) 2014-2017 Douglas Christopher Wilson
	* MIT Licensed
	*/

	'use strict'

	/**
	* Module dependencies.
	* @private
	*/

	var debug = require('debug')('finalhandler')
	var encodeUrl = require('encodeurl')
	var escapeHtml = require('escape-html')
	var onFinished = require('on-finished')
	var parseUrl = require('parseurl')
	var statuses = require('statuses')
	var unpipe = require('unpipe')

	/**
	* Module variables.
	* @private
	*/

	var DOUBLE_SPACE_REGEXP = /\x20{2}/g
	var NEWLINE_REGEXP = /\n/g

	/* istanbul ignore next */
	var defer = typeof setImmediate === 'function'
	? setImmediate
	: function (fn) { process.nextTick(fn.bind.apply(fn, arguments)) }
	var isFinished = onFinished.isFinished

	/**
	* Create a minimal HTML document.
	*
	* @param {string} message
	* @private
	*/

	function createHtmlDocument (message) {
	var body = escapeHtml(message)
	.replace(NEWLINE_REGEXP, '<br>')
	.replace(DOUBLE_SPACE_REGEXP, '  ')

	return '<!DOCTYPE html>\n' +
	'<html lang="en">\n' +
	'<head>\n' +
	'<meta charset="utf-8">\n' +
	'<title>Error</title>\n' +
	'</head>\n' +
	'<body>\n' +
	'<pre>' + body + '</pre>\n' +
	'</body>\n' +
	'</html>\n'
	}

	/**
	* 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
	var msg
	var status

	// ignore 404 on in-flight response
	if (!err && headersSent(res)) {
	debug('cannot 404 after headers sent')
	return
	}

	// unhandled error
	if (err) {
	// respect status code from error
	status = getErrorStatusCode(err)

	if (status === undefined) {
	// fallback to status code on response
	status = getResponseStatusCode(res)
	} else {
	// respect headers from error
	headers = getErrorHeaders(err)
	}

	// get error message
	msg = getErrorMessage(err, status, env)
	} else {
	// not found
	status = 404
	msg = 'Cannot ' + req.method + ' ' + encodeUrl(getResourceName(req))
	}

	debug('default %s', status)

	// schedule onerror callback
	if (err && onerror) {
	defer(onerror, err, req, res)
	}

	// cannot actually respond
	if (headersSent(res)) {
	debug('cannot %d after headers sent', status)
	req.socket.destroy()
	return
	}

	// send response
	send(req, res, status, headers, msg)
	}
	}

	/**
	* Get headers from Error object.
	*
	* @param {Error} err
	* @return {object}
	* @private
	*/

	function getErrorHeaders (err) {
	if (!err.headers \|\| typeof err.headers !== 'object') {
	return undefined
	}

	var headers = Object.create(null)
	var keys = Object.keys(err.headers)

	for (var i = 0; i < keys.length; i++) {
	var key = keys[i]
	headers[key] = err.headers[key]
	}

	return headers
	}

	/**
	* Get message from Error object, fallback to status message.
	*
	* @param {Error} err
	* @param {number} status
	* @param {string} env
	* @return {string}
	* @private
	*/

	function getErrorMessage (err, status, env) {
	var msg

	if (env !== 'production') {
	// use err.stack, which typically includes err.message
	msg = err.stack

	// fallback to err.toString() when possible
	if (!msg && typeof err.toString === 'function') {
	msg = err.toString()
	}
	}

	return msg \|\| statuses[status]
	}

	/**
	* 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
	}

	/**
	* Get resource name for the request.
	*
	* This is typically just the original pathname of the request
	* but will fallback to "resource" is that cannot be determined.
	*
	* @param {IncomingMessage} req
	* @return {string}
	* @private
	*/

	function getResourceName (req) {
	try {
	return parseUrl.original(req).pathname
	} catch (e) {
	return 'resource'
	}
	}

	/**
	* Get status code from response.
	*
	* @param {OutgoingMessage} res
	* @return {number}
	* @private
	*/

	function getResponseStatusCode (res) {
	var status = res.statusCode

	// default status code to 500 if outside valid range
	if (typeof status !== 'number' \|\| status < 400 \|\| status > 599) {
	status = 500
	}

	return status
	}

	/**
	* Determine if the response headers have been sent.
	*
	* @param {object} res
	* @returns {boolean}
	* @private
	*/

	function headersSent (res) {
	return typeof res.headersSent !== 'boolean'
	? Boolean(res._header)
	: res.headersSent
	}

	/**
	* Send response.
	*
	* @param {IncomingMessage} req
	* @param {OutgoingMessage} res
	* @param {number} status
	* @param {object} headers
	* @param {string} message
	* @private
	*/

	function send (req, res, status, headers, message) {
	function write () {
	// response body
	var body = createHtmlDocument(message)

	// response status
	res.statusCode = status
	res.statusMessage = statuses[status]

	// response headers
	setHeaders(res, headers)

	// security headers
	res.setHeader('Content-Security-Policy', "default-src 'none'")
	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()
	}

	/**
	* Set response headers from an object.
	*
	* @param {OutgoingMessage} res
	* @param {object} headers
	* @private
	*/

	function setHeaders (res, headers) {
	if (!headers) {
	return
	}

	var keys = Object.keys(headers)
	for (var i = 0; i < keys.length; i++) {
	var key = keys[i]
	res.setHeader(key, headers[key])
	}
	}