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agentscope-sift / node_modules /finalhandler /index.js

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	/*!
	* finalhandler
	* Copyright(c) 2014-2022 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')

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

	var isFinished = onFinished.isFinished

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

	function createHtmlDocument (message) {
	var body = escapeHtml(message)
	.replaceAll('\n', '<br>')
	.replaceAll(' ', '  ')

	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 && res.headersSent) {
	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) {
	setImmediate(onerror, err, req, res)
	}

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

	return { ...err.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.message[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
	}

	/**
	* 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

	if (req.httpVersionMajor < 2) {
	res.statusMessage = statuses.message[status]
	}

	// remove any content headers
	res.removeHeader('Content-Encoding')
	res.removeHeader('Content-Language')
	res.removeHeader('Content-Range')

	// response headers
	for (const [key, value] of Object.entries(headers ?? {})) {
	res.setHeader(key, value)
	}

	// 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
	req.unpipe()

	// flush the request
	onFinished(req, write)
	req.resume()
	}