1 files changed, 1133 insertions, 0 deletions
diff --git a/middleware/node_modules/send/index.js b/middleware/node_modules/send/index.js
new file mode 100644
index 0000000..06d7507
--- /dev/null
+++ b/middleware/node_modules/send/index.js
@@ -0,0 +1,1133 @@
+/*!
+ * send
+ * Copyright(c) 2012 TJ Holowaychuk
+ * Copyright(c) 2014-2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var createError = require('http-errors')
+var debug = require('debug')('send')
+var deprecate = require('depd')('send')
+var destroy = require('destroy')
+var encodeUrl = require('encodeurl')
+var escapeHtml = require('escape-html')
+var etag = require('etag')
+var fresh = require('fresh')
+var fs = require('fs')
+var mime = require('mime')
+var ms = require('ms')
+var onFinished = require('on-finished')
+var parseRange = require('range-parser')
+var path = require('path')
+var statuses = require('statuses')
+var Stream = require('stream')
+var util = require('util')
+
+/**
+ * Path function references.
+ * @private
+ */
+
+var extname = path.extname
+var join = path.join
+var normalize = path.normalize
+var resolve = path.resolve
+var sep = path.sep
+
+/**
+ * Regular expression for identifying a bytes Range header.
+ * @private
+ */
+
+var BYTES_RANGE_REGEXP = /^ *bytes=/
+
+/**
+ * Maximum value allowed for the max age.
+ * @private
+ */
+
+var MAX_MAXAGE = 60 * 60 * 24 * 365 * 1000 // 1 year
+
+/**
+ * Regular expression to match a path with a directory up component.
+ * @private
+ */
+
+var UP_PATH_REGEXP = /(?:^|[\\/])\.\.(?:[\\/]|$)/
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = send
+module.exports.mime = mime
+
+/**
+ * Return a `SendStream` for `req` and `path`.
+ *
+ * @param {object} req
+ * @param {string} path
+ * @param {object} [options]
+ * @return {SendStream}
+ * @public
+ */
+
+function send (req, path, options) {
+  return new SendStream(req, path, options)
+}
+
+/**
+ * Initialize a `SendStream` with the given `path`.
+ *
+ * @param {Request} req
+ * @param {String} path
+ * @param {object} [options]
+ * @private
+ */
+
+function SendStream (req, path, options) {
+  Stream.call(this)
+
+  var opts = options || {}
+
+  this.options = opts
+  this.path = path
+  this.req = req
+
+  this._acceptRanges = opts.acceptRanges !== undefined
+    ? Boolean(opts.acceptRanges)
+    : true
+
+  this._cacheControl = opts.cacheControl !== undefined
+    ? Boolean(opts.cacheControl)
+    : true
+
+  this._etag = opts.etag !== undefined
+    ? Boolean(opts.etag)
+    : true
+
+  this._dotfiles = opts.dotfiles !== undefined
+    ? opts.dotfiles
+    : 'ignore'
+
+  if (this._dotfiles !== 'ignore' && this._dotfiles !== 'allow' && this._dotfiles !== 'deny') {
+    throw new TypeError('dotfiles option must be "allow", "deny", or "ignore"')
+  }
+
+  this._hidden = Boolean(opts.hidden)
+
+  if (opts.hidden !== undefined) {
+    deprecate('hidden: use dotfiles: \'' + (this._hidden ? 'allow' : 'ignore') + '\' instead')
+  }
+
+  // legacy support
+  if (opts.dotfiles === undefined) {
+    this._dotfiles = undefined
+  }
+
+  this._extensions = opts.extensions !== undefined
+    ? normalizeList(opts.extensions, 'extensions option')
+    : []
+
+  this._immutable = opts.immutable !== undefined
+    ? Boolean(opts.immutable)
+    : false
+
+  this._index = opts.index !== undefined
+    ? normalizeList(opts.index, 'index option')
+    : ['index.html']
+
+  this._lastModified = opts.lastModified !== undefined
+    ? Boolean(opts.lastModified)
+    : true
+
+  this._maxage = opts.maxAge || opts.maxage
+  this._maxage = typeof this._maxage === 'string'
+    ? ms(this._maxage)
+    : Number(this._maxage)
+  this._maxage = !isNaN(this._maxage)
+    ? Math.min(Math.max(0, this._maxage), MAX_MAXAGE)
+    : 0
+
+  this._root = opts.root
+    ? resolve(opts.root)
+    : null
+
+  if (!this._root && opts.from) {
+    this.from(opts.from)
+  }
+}
+
+/**
+ * Inherits from `Stream`.
+ */
+
+util.inherits(SendStream, Stream)
+
+/**
+ * Enable or disable etag generation.
+ *
+ * @param {Boolean} val
+ * @return {SendStream}
+ * @api public
+ */
+
+SendStream.prototype.etag = deprecate.function(function etag (val) {
+  this._etag = Boolean(val)
+  debug('etag %s', this._etag)
+  return this
+}, 'send.etag: pass etag as option')
+
+/**
+ * Enable or disable "hidden" (dot) files.
+ *
+ * @param {Boolean} path
+ * @return {SendStream}
+ * @api public
+ */
+
+SendStream.prototype.hidden = deprecate.function(function hidden (val) {
+  this._hidden = Boolean(val)
+  this._dotfiles = undefined
+  debug('hidden %s', this._hidden)
+  return this
+}, 'send.hidden: use dotfiles option')
+
+/**
+ * Set index `paths`, set to a falsy
+ * value to disable index support.
+ *
+ * @param {String|Boolean|Array} paths
+ * @return {SendStream}
+ * @api public
+ */
+
+SendStream.prototype.index = deprecate.function(function index (paths) {
+  var index = !paths ? [] : normalizeList(paths, 'paths argument')
+  debug('index %o', paths)
+  this._index = index
+  return this
+}, 'send.index: pass index as option')
+
+/**
+ * Set root `path`.
+ *
+ * @param {String} path
+ * @return {SendStream}
+ * @api public
+ */
+
+SendStream.prototype.root = function root (path) {
+  this._root = resolve(String(path))
+  debug('root %s', this._root)
+  return this
+}
+
+SendStream.prototype.from = deprecate.function(SendStream.prototype.root,
+  'send.from: pass root as option')
+
+SendStream.prototype.root = deprecate.function(SendStream.prototype.root,
+  'send.root: pass root as option')
+
+/**
+ * Set max-age to `maxAge`.
+ *
+ * @param {Number} maxAge
+ * @return {SendStream}
+ * @api public
+ */
+
+SendStream.prototype.maxage = deprecate.function(function maxage (maxAge) {
+  this._maxage = typeof maxAge === 'string'
+    ? ms(maxAge)
+    : Number(maxAge)
+  this._maxage = !isNaN(this._maxage)
+    ? Math.min(Math.max(0, this._maxage), MAX_MAXAGE)
+    : 0
+  debug('max-age %d', this._maxage)
+  return this
+}, 'send.maxage: pass maxAge as option')
+
+/**
+ * Emit error with `status`.
+ *
+ * @param {number} status
+ * @param {Error} [err]
+ * @private
+ */
+
+SendStream.prototype.error = function error (status, err) {
+  // emit if listeners instead of responding
+  if (hasListeners(this, 'error')) {
+    return this.emit('error', createError(status, err, {
+      expose: false
+    }))
+  }
+
+  var res = this.res
+  var msg = statuses[status] || String(status)
+  var doc = createHtmlDocument('Error', escapeHtml(msg))
+
+  // clear existing headers
+  clearHeaders(res)
+
+  // add error headers
+  if (err && err.headers) {
+    setHeaders(res, err.headers)
+  }
+
+  // send basic response
+  res.statusCode = status
+  res.setHeader('Content-Type', 'text/html; charset=UTF-8')
+  res.setHeader('Content-Length', Buffer.byteLength(doc))
+  res.setHeader('Content-Security-Policy', "default-src 'none'")
+  res.setHeader('X-Content-Type-Options', 'nosniff')
+  res.end(doc)
+}
+
+/**
+ * Check if the pathname ends with "/".
+ *
+ * @return {boolean}
+ * @private
+ */
+
+SendStream.prototype.hasTrailingSlash = function hasTrailingSlash () {
+  return this.path[this.path.length - 1] === '/'
+}
+
+/**
+ * Check if this is a conditional GET request.
+ *
+ * @return {Boolean}
+ * @api private
+ */
+
+SendStream.prototype.isConditionalGET = function isConditionalGET () {
+  return this.req.headers['if-match'] ||
+    this.req.headers['if-unmodified-since'] ||
+    this.req.headers['if-none-match'] ||
+    this.req.headers['if-modified-since']
+}
+
+/**
+ * Check if the request preconditions failed.
+ *
+ * @return {boolean}
+ * @private
+ */
+
+SendStream.prototype.isPreconditionFailure = function isPreconditionFailure () {
+  var req = this.req
+  var res = this.res
+
+  // if-match
+  var match = req.headers['if-match']
+  if (match) {
+    var etag = res.getHeader('ETag')
+    return !etag || (match !== '*' && parseTokenList(match).every(function (match) {
+      return match !== etag && match !== 'W/' + etag && 'W/' + match !== etag
+    }))
+  }
+
+  // if-unmodified-since
+  var unmodifiedSince = parseHttpDate(req.headers['if-unmodified-since'])
+  if (!isNaN(unmodifiedSince)) {
+    var lastModified = parseHttpDate(res.getHeader('Last-Modified'))
+    return isNaN(lastModified) || lastModified > unmodifiedSince
+  }
+
+  return false
+}
+
+/**
+ * Strip content-* header fields.
+ *
+ * @private
+ */
+
+SendStream.prototype.removeContentHeaderFields = function removeContentHeaderFields () {
+  var res = this.res
+  var headers = getHeaderNames(res)
+
+  for (var i = 0; i < headers.length; i++) {
+    var header = headers[i]
+    if (header.substr(0, 8) === 'content-' && header !== 'content-location') {
+      res.removeHeader(header)
+    }
+  }
+}
+
+/**
+ * Respond with 304 not modified.
+ *
+ * @api private
+ */
+
+SendStream.prototype.notModified = function notModified () {
+  var res = this.res
+  debug('not modified')
+  this.removeContentHeaderFields()
+  res.statusCode = 304
+  res.end()
+}
+
+/**
+ * Raise error that headers already sent.
+ *
+ * @api private
+ */
+
+SendStream.prototype.headersAlreadySent = function headersAlreadySent () {
+  var err = new Error('Can\'t set headers after they are sent.')
+  debug('headers already sent')
+  this.error(500, err)
+}
+
+/**
+ * Check if the request is cacheable, aka
+ * responded with 2xx or 304 (see RFC 2616 section 14.2{5,6}).
+ *
+ * @return {Boolean}
+ * @api private
+ */
+
+SendStream.prototype.isCachable = function isCachable () {
+  var statusCode = this.res.statusCode
+  return (statusCode >= 200 && statusCode < 300) ||
+    statusCode === 304
+}
+
+/**
+ * Handle stat() error.
+ *
+ * @param {Error} error
+ * @private
+ */
+
+SendStream.prototype.onStatError = function onStatError (error) {
+  switch (error.code) {
+    case 'ENAMETOOLONG':
+    case 'ENOENT':
+    case 'ENOTDIR':
+      this.error(404, error)
+      break
+    default:
+      this.error(500, error)
+      break
+  }
+}
+
+/**
+ * Check if the cache is fresh.
+ *
+ * @return {Boolean}
+ * @api private
+ */
+
+SendStream.prototype.isFresh = function isFresh () {
+  return fresh(this.req.headers, {
+    etag: this.res.getHeader('ETag'),
+    'last-modified': this.res.getHeader('Last-Modified')
+  })
+}
+
+/**
+ * Check if the range is fresh.
+ *
+ * @return {Boolean}
+ * @api private
+ */
+
+SendStream.prototype.isRangeFresh = function isRangeFresh () {
+  var ifRange = this.req.headers['if-range']
+
+  if (!ifRange) {
+    return true
+  }
+
+  // if-range as etag
+  if (ifRange.indexOf('"') !== -1) {
+    var etag = this.res.getHeader('ETag')
+    return Boolean(etag && ifRange.indexOf(etag) !== -1)
+  }
+
+  // if-range as modified date
+  var lastModified = this.res.getHeader('Last-Modified')
+  return parseHttpDate(lastModified) <= parseHttpDate(ifRange)
+}
+
+/**
+ * Redirect to path.
+ *
+ * @param {string} path
+ * @private
+ */
+
+SendStream.prototype.redirect = function redirect (path) {
+  var res = this.res
+
+  if (hasListeners(this, 'directory')) {
+    this.emit('directory', res, path)
+    return
+  }
+
+  if (this.hasTrailingSlash()) {
+    this.error(403)
+    return
+  }
+
+  var loc = encodeUrl(collapseLeadingSlashes(this.path + '/'))
+  var doc = createHtmlDocument('Redirecting', 'Redirecting to <a href="' + escapeHtml(loc) + '">' +
+    escapeHtml(loc) + '</a>')
+
+  // redirect
+  res.statusCode = 301
+  res.setHeader('Content-Type', 'text/html; charset=UTF-8')
+  res.setHeader('Content-Length', Buffer.byteLength(doc))
+  res.setHeader('Content-Security-Policy', "default-src 'none'")
+  res.setHeader('X-Content-Type-Options', 'nosniff')
+  res.setHeader('Location', loc)
+  res.end(doc)
+}
+
+/**
+ * Pipe to `res.
+ *
+ * @param {Stream} res
+ * @return {Stream} res
+ * @api public
+ */
+
+SendStream.prototype.pipe = function pipe (res) {
+  // root path
+  var root = this._root
+
+  // references
+  this.res = res
+
+  // decode the path
+  var path = decode(this.path)
+  if (path === -1) {
+    this.error(400)
+    return res
+  }
+
+  // null byte(s)
+  if (~path.indexOf('\0')) {
+    this.error(400)
+    return res
+  }
+
+  var parts
+  if (root !== null) {
+    // normalize
+    if (path) {
+      path = normalize('.' + sep + path)
+    }
+
+    // malicious path
+    if (UP_PATH_REGEXP.test(path)) {
+      debug('malicious path "%s"', path)
+      this.error(403)
+      return res
+    }
+
+    // explode path parts
+    parts = path.split(sep)
+
+    // join / normalize from optional root dir
+    path = normalize(join(root, path))
+  } else {
+    // ".." is malicious without "root"
+    if (UP_PATH_REGEXP.test(path)) {
+      debug('malicious path "%s"', path)
+      this.error(403)
+      return res
+    }
+
+    // explode path parts
+    parts = normalize(path).split(sep)
+
+    // resolve the path
+    path = resolve(path)
+  }
+
+  // dotfile handling
+  if (containsDotFile(parts)) {
+    var access = this._dotfiles
+
+    // legacy support
+    if (access === undefined) {
+      access = parts[parts.length - 1][0] === '.'
+        ? (this._hidden ? 'allow' : 'ignore')
+        : 'allow'
+    }
+
+    debug('%s dotfile "%s"', access, path)
+    switch (access) {
+      case 'allow':
+        break
+      case 'deny':
+        this.error(403)
+        return res
+      case 'ignore':
+      default:
+        this.error(404)
+        return res
+    }
+  }
+
+  // index file support
+  if (this._index.length && this.hasTrailingSlash()) {
+    this.sendIndex(path)
+    return res
+  }
+
+  this.sendFile(path)
+  return res
+}
+
+/**
+ * Transfer `path`.
+ *
+ * @param {String} path
+ * @api public
+ */
+
+SendStream.prototype.send = function send (path, stat) {
+  var len = stat.size
+  var options = this.options
+  var opts = {}
+  var res = this.res
+  var req = this.req
+  var ranges = req.headers.range
+  var offset = options.start || 0
+
+  if (headersSent(res)) {
+    // impossible to send now
+    this.headersAlreadySent()
+    return
+  }
+
+  debug('pipe "%s"', path)
+
+  // set header fields
+  this.setHeader(path, stat)
+
+  // set content-type
+  this.type(path)
+
+  // conditional GET support
+  if (this.isConditionalGET()) {
+    if (this.isPreconditionFailure()) {
+      this.error(412)
+      return
+    }
+
+    if (this.isCachable() && this.isFresh()) {
+      this.notModified()
+      return
+    }
+  }
+
+  // adjust len to start/end options
+  len = Math.max(0, len - offset)
+  if (options.end !== undefined) {
+    var bytes = options.end - offset + 1
+    if (len > bytes) len = bytes
+  }
+
+  // Range support
+  if (this._acceptRanges && BYTES_RANGE_REGEXP.test(ranges)) {
+    // parse
+    ranges = parseRange(len, ranges, {
+      combine: true
+    })
+
+    // If-Range support
+    if (!this.isRangeFresh()) {
+      debug('range stale')
+      ranges = -2
+    }
+
+    // unsatisfiable
+    if (ranges === -1) {
+      debug('range unsatisfiable')
+
+      // Content-Range
+      res.setHeader('Content-Range', contentRange('bytes', len))
+
+      // 416 Requested Range Not Satisfiable
+      return this.error(416, {
+        headers: { 'Content-Range': res.getHeader('Content-Range') }
+      })
+    }
+
+    // valid (syntactically invalid/multiple ranges are treated as a regular response)
+    if (ranges !== -2 && ranges.length === 1) {
+      debug('range %j', ranges)
+
+      // Content-Range
+      res.statusCode = 206
+      res.setHeader('Content-Range', contentRange('bytes', len, ranges[0]))
+
+      // adjust for requested range
+      offset += ranges[0].start
+      len = ranges[0].end - ranges[0].start + 1
+    }
+  }
+
+  // clone options
+  for (var prop in options) {
+    opts[prop] = options[prop]
+  }
+
+  // set read options
+  opts.start = offset
+  opts.end = Math.max(offset, offset + len - 1)
+
+  // content-length
+  res.setHeader('Content-Length', len)
+
+  // HEAD support
+  if (req.method === 'HEAD') {
+    res.end()
+    return
+  }
+
+  this.stream(path, opts)
+}
+
+/**
+ * Transfer file for `path`.
+ *
+ * @param {String} path
+ * @api private
+ */
+SendStream.prototype.sendFile = function sendFile (path) {
+  var i = 0
+  var self = this
+
+  debug('stat "%s"', path)
+  fs.stat(path, function onstat (err, stat) {
+    if (err && err.code === 'ENOENT' && !extname(path) && path[path.length - 1] !== sep) {
+      // not found, check extensions
+      return next(err)
+    }
+    if (err) return self.onStatError(err)
+    if (stat.isDirectory()) return self.redirect(path)
+    self.emit('file', path, stat)
+    self.send(path, stat)
+  })
+
+  function next (err) {
+    if (self._extensions.length <= i) {
+      return err
+        ? self.onStatError(err)
+        : self.error(404)
+    }
+
+    var p = path + '.' + self._extensions[i++]
+
+    debug('stat "%s"', p)
+    fs.stat(p, function (err, stat) {
+      if (err) return next(err)
+      if (stat.isDirectory()) return next()
+      self.emit('file', p, stat)
+      self.send(p, stat)
+    })
+  }
+}
+
+/**
+ * Transfer index for `path`.
+ *
+ * @param {String} path
+ * @api private
+ */
+SendStream.prototype.sendIndex = function sendIndex (path) {
+  var i = -1
+  var self = this
+
+  function next (err) {
+    if (++i >= self._index.length) {
+      if (err) return self.onStatError(err)
+      return self.error(404)
+    }
+
+    var p = join(path, self._index[i])
+
+    debug('stat "%s"', p)
+    fs.stat(p, function (err, stat) {
+      if (err) return next(err)
+      if (stat.isDirectory()) return next()
+      self.emit('file', p, stat)
+      self.send(p, stat)
+    })
+  }
+
+  next()
+}
+
+/**
+ * Stream `path` to the response.
+ *
+ * @param {String} path
+ * @param {Object} options
+ * @api private
+ */
+
+SendStream.prototype.stream = function stream (path, options) {
+  // TODO: this is all lame, refactor meeee
+  var finished = false
+  var self = this
+  var res = this.res
+
+  // pipe
+  var stream = fs.createReadStream(path, options)
+  this.emit('stream', stream)
+  stream.pipe(res)
+
+  // response finished, done with the fd
+  onFinished(res, function onfinished () {
+    finished = true
+    destroy(stream)
+  })
+
+  // error handling code-smell
+  stream.on('error', function onerror (err) {
+    // request already finished
+    if (finished) return
+
+    // clean up stream
+    finished = true
+    destroy(stream)
+
+    // error
+    self.onStatError(err)
+  })
+
+  // end
+  stream.on('end', function onend () {
+    self.emit('end')
+  })
+}
+
+/**
+ * Set content-type based on `path`
+ * if it hasn't been explicitly set.
+ *
+ * @param {String} path
+ * @api private
+ */
+
+SendStream.prototype.type = function type (path) {
+  var res = this.res
+
+  if (res.getHeader('Content-Type')) return
+
+  var type = mime.lookup(path)
+
+  if (!type) {
+    debug('no content-type')
+    return
+  }
+
+  var charset = mime.charsets.lookup(type)
+
+  debug('content-type %s', type)
+  res.setHeader('Content-Type', type + (charset ? '; charset=' + charset : ''))
+}
+
+/**
+ * Set response header fields, most
+ * fields may be pre-defined.
+ *
+ * @param {String} path
+ * @param {Object} stat
+ * @api private
+ */
+
+SendStream.prototype.setHeader = function setHeader (path, stat) {
+  var res = this.res
+
+  this.emit('headers', res, path, stat)
+
+  if (this._acceptRanges && !res.getHeader('Accept-Ranges')) {
+    debug('accept ranges')
+    res.setHeader('Accept-Ranges', 'bytes')
+  }
+
+  if (this._cacheControl && !res.getHeader('Cache-Control')) {
+    var cacheControl = 'public, max-age=' + Math.floor(this._maxage / 1000)
+
+    if (this._immutable) {
+      cacheControl += ', immutable'
+    }
+
+    debug('cache-control %s', cacheControl)
+    res.setHeader('Cache-Control', cacheControl)
+  }
+
+  if (this._lastModified && !res.getHeader('Last-Modified')) {
+    var modified = stat.mtime.toUTCString()
+    debug('modified %s', modified)
+    res.setHeader('Last-Modified', modified)
+  }
+
+  if (this._etag && !res.getHeader('ETag')) {
+    var val = etag(stat)
+    debug('etag %s', val)
+    res.setHeader('ETag', val)
+  }
+}
+
+/**
+ * Clear all headers from a response.
+ *
+ * @param {object} res
+ * @private
+ */
+
+function clearHeaders (res) {
+  var headers = getHeaderNames(res)
+
+  for (var i = 0; i < headers.length; i++) {
+    res.removeHeader(headers[i])
+  }
+}
+
+/**
+ * Collapse all leading slashes into a single slash
+ *
+ * @param {string} str
+ * @private
+ */
+function collapseLeadingSlashes (str) {
+  for (var i = 0; i < str.length; i++) {
+    if (str[i] !== '/') {
+      break
+    }
+  }
+
+  return i > 1
+    ? '/' + str.substr(i)
+    : str
+}
+
+/**
+ * Determine if path parts contain a dotfile.
+ *
+ * @api private
+ */
+
+function containsDotFile (parts) {
+  for (var i = 0; i < parts.length; i++) {
+    var part = parts[i]
+    if (part.length > 1 && part[0] === '.') {
+      return true
+    }
+  }
+
+  return false
+}
+
+/**
+ * Create a Content-Range header.
+ *
+ * @param {string} type
+ * @param {number} size
+ * @param {array} [range]
+ */
+
+function contentRange (type, size, range) {
+  return type + ' ' + (range ? range.start + '-' + range.end : '*') + '/' + size
+}
+
+/**
+ * Create a minimal HTML document.
+ *
+ * @param {string} title
+ * @param {string} body
+ * @private
+ */
+
+function createHtmlDocument (title, body) {
+  return '<!DOCTYPE html>\n' +
+    '<html lang="en">\n' +
+    '<head>\n' +
+    '<meta charset="utf-8">\n' +
+    '<title>' + title + '</title>\n' +
+    '</head>\n' +
+    '<body>\n' +
+    '<pre>' + body + '</pre>\n' +
+    '</body>\n' +
+    '</html>\n'
+}
+
+/**
+ * decodeURIComponent.
+ *
+ * Allows V8 to only deoptimize this fn instead of all
+ * of send().
+ *
+ * @param {String} path
+ * @api private
+ */
+
+function decode (path) {
+  try {
+    return decodeURIComponent(path)
+  } catch (err) {
+    return -1
+  }
+}
+
+/**
+ * Get the header names on a respnse.
+ *
+ * @param {object} res
+ * @returns {array[string]}
+ * @private
+ */
+
+function getHeaderNames (res) {
+  return typeof res.getHeaderNames !== 'function'
+    ? Object.keys(res._headers || {})
+    : res.getHeaderNames()
+}
+
+/**
+ * Determine if emitter has listeners of a given type.
+ *
+ * The way to do this check is done three different ways in Node.js >= 0.8
+ * so this consolidates them into a minimal set using instance methods.
+ *
+ * @param {EventEmitter} emitter
+ * @param {string} type
+ * @returns {boolean}
+ * @private
+ */
+
+function hasListeners (emitter, type) {
+  var count = typeof emitter.listenerCount !== 'function'
+    ? emitter.listeners(type).length
+    : emitter.listenerCount(type)
+
+  return count > 0
+}
+
+/**
+ * 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
+}
+
+/**
+ * Normalize the index option into an array.
+ *
+ * @param {boolean|string|array} val
+ * @param {string} name
+ * @private
+ */
+
+function normalizeList (val, name) {
+  var list = [].concat(val || [])
+
+  for (var i = 0; i < list.length; i++) {
+    if (typeof list[i] !== 'string') {
+      throw new TypeError(name + ' must be array of strings or false')
+    }
+  }
+
+  return list
+}
+
+/**
+ * Parse an HTTP Date into a number.
+ *
+ * @param {string} date
+ * @private
+ */
+
+function parseHttpDate (date) {
+  var timestamp = date && Date.parse(date)
+
+  return typeof timestamp === 'number'
+    ? timestamp
+    : NaN
+}
+
+/**
+ * Parse a HTTP token list.
+ *
+ * @param {string} str
+ * @private
+ */
+
+function parseTokenList (str) {
+  var end = 0
+  var list = []
+  var start = 0
+
+  // gather tokens
+  for (var i = 0, len = str.length; i < len; i++) {
+    switch (str.charCodeAt(i)) {
+      case 0x20: /*   */
+        if (start === end) {
+          start = end = i + 1
+        }
+        break
+      case 0x2c: /* , */
+        if (start !== end) {
+          list.push(str.substring(start, end))
+        }
+        start = end = i + 1
+        break
+      default:
+        end = i + 1
+        break
+    }
+  }
+
+  // final token
+  if (start !== end) {
+    list.push(str.substring(start, end))
+  }
+
+  return list
+}
+
+/**
+ * Set an object of headers on a response.
+ *
+ * @param {object} res
+ * @param {object} headers
+ * @private
+ */
+
+function setHeaders (res, headers) {
+  var keys = Object.keys(headers)
+
+  for (var i = 0; i < keys.length; i++) {
+    var key = keys[i]
+    res.setHeader(key, headers[key])
+  }
+}