index.js

      stream.Stream.prototype.pipe.call(self, dest, opts)
      self.pipeDest(dest)
      return dest
    }
  } else {
    self.dests.push(dest)
    stream.Stream.prototype.pipe.call(self, dest, opts)
    return dest
  }
}
Request.prototype.write = function () {
  var self = this
  if (self._aborted) { return }

  if (!self._started) {
    self.start()
  }
  if (self.req) {
    return self.req.write.apply(self.req, arguments)
  }
}
Request.prototype.end = function (chunk) {
  var self = this
  if (self._aborted) { return }

  if (chunk) {
    self.write(chunk)
  }
  if (!self._started) {
    self.start()
  }
  if (self.req) {
    self.req.end()
  }
}
Request.prototype.pause = function () {
  var self = this
  if (!self.responseContent) {
    self._paused = true
  } else {
    self.responseContent.pause.apply(self.responseContent, arguments)
  }
}
Request.prototype.resume = function () {
  var self = this
  if (!self.responseContent) {
    self._paused = false
  } else {
    self.responseContent.resume.apply(self.responseContent, arguments)
  }
}
Request.prototype.destroy = function () {
  var self = this
  this.clearTimeout()
  if (!self._ended) {
    self.end()
  } else if (self.response) {
    self.response.destroy()
  }
}

Request.prototype.clearTimeout = function () {
  if (this.timeoutTimer) {
    clearTimeout(this.timeoutTimer)
    this.timeoutTimer = null
  }
}

Request.defaultProxyHeaderWhiteList =
  Tunnel.defaultProxyHeaderWhiteList.slice()

Request.defaultProxyHeaderExclusiveList =
  Tunnel.defaultProxyHeaderExclusiveList.slice()

// Exports

Request.prototype.toJSON = requestToJSON
module.exports = Request


/***/ }),
/* 98 */
/***/ (function(module, exports) {

module.exports = require("http");

/***/ }),
/* 99 */
/***/ (function(module, exports) {

module.exports = require("https");

/***/ }),
/* 100 */
/***/ (function(module, exports) {

module.exports = require("stream");

/***/ }),
/* 101 */
/***/ (function(module, exports) {

module.exports = require("zlib");

/***/ }),
/* 102 */
/***/ (function(module, exports, __webpack_require__) {


/*!
 *  Copyright 2010 LearnBoost <dev@learnboost.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Module dependencies.
 */

var crypto = __webpack_require__(94)
  , parse = __webpack_require__(83).parse
  ;

/**
 * Valid keys.
 */

var keys = 
  [ 'acl'
  , 'location'
  , 'logging'
  , 'notification'
  , 'partNumber'
  , 'policy'
  , 'requestPayment'
  , 'torrent'
  , 'uploadId'
  , 'uploads'
  , 'versionId'
  , 'versioning'
  , 'versions'
  , 'website'
  ]

/**
 * Return an "Authorization" header value with the given `options`
 * in the form of "AWS <key>:<signature>"
 *
 * @param {Object} options
 * @return {String}
 * @api private
 */

function authorization (options) {
  return 'AWS ' + options.key + ':' + sign(options)
}

module.exports = authorization
module.exports.authorization = authorization

/**
 * Simple HMAC-SHA1 Wrapper
 *
 * @param {Object} options
 * @return {String}
 * @api private
 */ 

function hmacSha1 (options) {
  return crypto.createHmac('sha1', options.secret).update(options.message).digest('base64')
}

module.exports.hmacSha1 = hmacSha1

/**
 * Create a base64 sha1 HMAC for `options`. 
 * 
 * @param {Object} options
 * @return {String}
 * @api private
 */

function sign (options) {
  options.message = stringToSign(options)
  return hmacSha1(options)
}
module.exports.sign = sign

/**
 * Create a base64 sha1 HMAC for `options`. 
 *
 * Specifically to be used with S3 presigned URLs
 * 
 * @param {Object} options
 * @return {String}
 * @api private
 */

function signQuery (options) {
  options.message = queryStringToSign(options)
  return hmacSha1(options)
}
module.exports.signQuery= signQuery

/**
 * Return a string for sign() with the given `options`.
 *
 * Spec:
 * 
 *    <verb>\n
 *    <md5>\n
 *    <content-type>\n
 *    <date>\n
 *    [headers\n]
 *    <resource>
 *
 * @param {Object} options
 * @return {String}
 * @api private
 */

function stringToSign (options) {
  var headers = options.amazonHeaders || ''
  if (headers) headers += '\n'
  var r = 
    [ options.verb
    , options.md5
    , options.contentType
    , options.date ? options.date.toUTCString() : ''
    , headers + options.resource
    ]
  return r.join('\n')
}
module.exports.stringToSign = stringToSign

/**
 * Return a string for sign() with the given `options`, but is meant exclusively
 * for S3 presigned URLs
 *
 * Spec:
 * 
 *    <date>\n
 *    <resource>
 *
 * @param {Object} options
 * @return {String}
 * @api private
 */

function queryStringToSign (options){
  return 'GET\n\n\n' + options.date + '\n' + options.resource
}
module.exports.queryStringToSign = queryStringToSign

/**
 * Perform the following:
 *
 *  - ignore non-amazon headers
 *  - lowercase fields
 *  - sort lexicographically
 *  - trim whitespace between ":"
 *  - join with newline
 *
 * @param {Object} headers
 * @return {String}
 * @api private
 */

function canonicalizeHeaders (headers) {
  var buf = []
    , fields = Object.keys(headers)
    ;
  for (var i = 0, len = fields.length; i < len; ++i) {
    var field = fields[i]
      , val = headers[field]
      , field = field.toLowerCase()
      ;
    if (0 !== field.indexOf('x-amz')) continue
    buf.push(field + ':' + val)
  }
  return buf.sort().join('\n')
}
module.exports.canonicalizeHeaders = canonicalizeHeaders

/**
 * Perform the following:
 *
 *  - ignore non sub-resources
 *  - sort lexicographically
 *
 * @param {String} resource
 * @return {String}
 * @api private
 */

function canonicalizeResource (resource) {
  var url = parse(resource, true)
    , path = url.pathname
    , buf = []
    ;

  Object.keys(url.query).forEach(function(key){
    if (!~keys.indexOf(key)) return
    var val = '' == url.query[key] ? '' : '=' + encodeURIComponent(url.query[key])
    buf.push(key + val)
  })

  return path + (buf.length ? '?' + buf.sort().join('&') : '')
}
module.exports.canonicalizeResource = canonicalizeResource


/***/ }),
/* 103 */
/***/ (function(module, exports, __webpack_require__) {

var aws4 = exports,
    url = __webpack_require__(83),
    querystring = __webpack_require__(104),
    crypto = __webpack_require__(94),
    lru = __webpack_require__(105),
    credentialsCache = lru(1000)

// http://docs.amazonwebservices.com/general/latest/gr/signature-version-4.html

function hmac(key, string, encoding) {
  return crypto.createHmac('sha256', key).update(string, 'utf8').digest(encoding)
}

function hash(string, encoding) {
  return crypto.createHash('sha256').update(string, 'utf8').digest(encoding)
}

// This function assumes the string has already been percent encoded
function encodeRfc3986(urlEncodedString) {
  return urlEncodedString.replace(/[!'()*]/g, function(c) {
    return '%' + c.charCodeAt(0).toString(16).toUpperCase()
  })
}

function encodeRfc3986Full(str) {
  return encodeRfc3986(encodeURIComponent(str))
}

// A bit of a combination of:
// https://github.com/aws/aws-sdk-java-v2/blob/dc695de6ab49ad03934e1b02e7263abbd2354be0/core/auth/src/main/java/software/amazon/awssdk/auth/signer/internal/AbstractAws4Signer.java#L59
// https://github.com/aws/aws-sdk-js/blob/18cb7e5b463b46239f9fdd4a65e2ff8c81831e8f/lib/signers/v4.js#L191-L199
// https://github.com/mhart/aws4fetch/blob/b3aed16b6f17384cf36ea33bcba3c1e9f3bdfefd/src/main.js#L25-L34
var HEADERS_TO_IGNORE = {
  'authorization': true,
  'connection': true,
  'x-amzn-trace-id': true,
  'user-agent': true,
  'expect': true,
  'presigned-expires': true,
  'range': true,
}

// request: { path | body, [host], [method], [headers], [service], [region] }
// credentials: { accessKeyId, secretAccessKey, [sessionToken] }
function RequestSigner(request, credentials) {

  if (typeof request === 'string') request = url.parse(request)

  var headers = request.headers = (request.headers || {}),
      hostParts = (!this.service || !this.region) && this.matchHost(request.hostname || request.host || headers.Host || headers.host)

  this.request = request
  this.credentials = credentials || this.defaultCredentials()

  this.service = request.service || hostParts[0] || ''
  this.region = request.region || hostParts[1] || 'us-east-1'

  // SES uses a different domain from the service name
  if (this.service === 'email') this.service = 'ses'

  if (!request.method && request.body)
    request.method = 'POST'

  if (!headers.Host && !headers.host) {
    headers.Host = request.hostname || request.host || this.createHost()

    // If a port is specified explicitly, use it as is
    if (request.port)
      headers.Host += ':' + request.port
  }
  if (!request.hostname && !request.host)
    request.hostname = headers.Host || headers.host

  this.isCodeCommitGit = this.service === 'codecommit' && request.method === 'GIT'
}

RequestSigner.prototype.matchHost = function(host) {
  var match = (host || '').match(/([^\.]+)\.(?:([^\.]*)\.)?amazonaws\.com(\.cn)?$/)
  var hostParts = (match || []).slice(1, 3)

  // ES's hostParts are sometimes the other way round, if the value that is expected
  // to be region equals ‘es’ switch them back
  // e.g. search-cluster-name-aaaa00aaaa0aaa0aaaaaaa0aaa.us-east-1.es.amazonaws.com
  if (hostParts[1] === 'es')
    hostParts = hostParts.reverse()

  if (hostParts[1] == 's3') {
    hostParts[0] = 's3'
    hostParts[1] = 'us-east-1'
  } else {
    for (var i = 0; i < 2; i++) {
      if (/^s3-/.test(hostParts[i])) {
        hostParts[1] = hostParts[i].slice(3)
        hostParts[0] = 's3'
        break
      }
    }
  }

  return hostParts
}

// http://docs.aws.amazon.com/general/latest/gr/rande.html
RequestSigner.prototype.isSingleRegion = function() {
  // Special case for S3 and SimpleDB in us-east-1
  if (['s3', 'sdb'].indexOf(this.service) >= 0 && this.region === 'us-east-1') return true

  return ['cloudfront', 'ls', 'route53', 'iam', 'importexport', 'sts']
    .indexOf(this.service) >= 0
}

RequestSigner.prototype.createHost = function() {
  var region = this.isSingleRegion() ? '' : '.' + this.region,
      subdomain = this.service === 'ses' ? 'email' : this.service
  return subdomain + region + '.amazonaws.com'
}

RequestSigner.prototype.prepareRequest = function() {
  this.parsePath()

  var request = this.request, headers = request.headers, query

  if (request.signQuery) {

    this.parsedPath.query = query = this.parsedPath.query || {}

    if (this.credentials.sessionToken)
      query['X-Amz-Security-Token'] = this.credentials.sessionToken

    if (this.service === 's3' && !query['X-Amz-Expires'])
      query['X-Amz-Expires'] = 86400

    if (query['X-Amz-Date'])
      this.datetime = query['X-Amz-Date']
    else
      query['X-Amz-Date'] = this.getDateTime()

    query['X-Amz-Algorithm'] = 'AWS4-HMAC-SHA256'
    query['X-Amz-Credential'] = this.credentials.accessKeyId + '/' + this.credentialString()
    query['X-Amz-SignedHeaders'] = this.signedHeaders()

  } else {

    if (!request.doNotModifyHeaders && !this.isCodeCommitGit) {
      if (request.body && !headers['Content-Type'] && !headers['content-type'])
        headers['Content-Type'] = 'application/x-www-form-urlencoded; charset=utf-8'

      if (request.body && !headers['Content-Length'] && !headers['content-length'])
        headers['Content-Length'] = Buffer.byteLength(request.body)

      if (this.credentials.sessionToken && !headers['X-Amz-Security-Token'] && !headers['x-amz-security-token'])
        headers['X-Amz-Security-Token'] = this.credentials.sessionToken

      if (this.service === 's3' && !headers['X-Amz-Content-Sha256'] && !headers['x-amz-content-sha256'])
        headers['X-Amz-Content-Sha256'] = hash(this.request.body || '', 'hex')

      if (headers['X-Amz-Date'] || headers['x-amz-date'])
        this.datetime = headers['X-Amz-Date'] || headers['x-amz-date']
      else
        headers['X-Amz-Date'] = this.getDateTime()
    }

    delete headers.Authorization
    delete headers.authorization
  }
}

RequestSigner.prototype.sign = function() {
  if (!this.parsedPath) this.prepareRequest()

  if (this.request.signQuery) {
    this.parsedPath.query['X-Amz-Signature'] = this.signature()
  } else {
    this.request.headers.Authorization = this.authHeader()
  }

  this.request.path = this.formatPath()

  return this.request
}

RequestSigner.prototype.getDateTime = function() {
  if (!this.datetime) {
    var headers = this.request.headers,
      date = new Date(headers.Date || headers.date || new Date)

    this.datetime = date.toISOString().replace(/[:\-]|\.\d{3}/g, '')

    // Remove the trailing 'Z' on the timestamp string for CodeCommit git access
    if (this.isCodeCommitGit) this.datetime = this.datetime.slice(0, -1)
  }
  return this.datetime
}

RequestSigner.prototype.getDate = function() {
  return this.getDateTime().substr(0, 8)
}

RequestSigner.prototype.authHeader = function() {
  return [
    'AWS4-HMAC-SHA256 Credential=' + this.credentials.accessKeyId + '/' + this.credentialString(),
    'SignedHeaders=' + this.signedHeaders(),
    'Signature=' + this.signature(),
  ].join(', ')
}

RequestSigner.prototype.signature = function() {
  var date = this.getDate(),
      cacheKey = [this.credentials.secretAccessKey, date, this.region, this.service].join(),
      kDate, kRegion, kService, kCredentials = credentialsCache.get(cacheKey)
  if (!kCredentials) {
    kDate = hmac('AWS4' + this.credentials.secretAccessKey, date)
    kRegion = hmac(kDate, this.region)
    kService = hmac(kRegion, this.service)
    kCredentials = hmac(kService, 'aws4_request')
    credentialsCache.set(cacheKey, kCredentials)
  }
  return hmac(kCredentials, this.stringToSign(), 'hex')
}

RequestSigner.prototype.stringToSign = function() {
  return [
    'AWS4-HMAC-SHA256',
    this.getDateTime(),
    this.credentialString(),
    hash(this.canonicalString(), 'hex'),
  ].join('\n')
}

RequestSigner.prototype.canonicalString = function() {
  if (!this.parsedPath) this.prepareRequest()

  var pathStr = this.parsedPath.path,
      query = this.parsedPath.query,
      headers = this.request.headers,
      queryStr = '',
      normalizePath = this.service !== 's3',
      decodePath = this.service === 's3' || this.request.doNotEncodePath,
      decodeSlashesInPath = this.service === 's3',
      firstValOnly = this.service === 's3',
      bodyHash

  if (this.service === 's3' && this.request.signQuery) {
    bodyHash = 'UNSIGNED-PAYLOAD'
  } else if (this.isCodeCommitGit) {
    bodyHash = ''
  } else {
    bodyHash = headers['X-Amz-Content-Sha256'] || headers['x-amz-content-sha256'] ||
      hash(this.request.body || '', 'hex')
  }

  if (query) {
    var reducedQuery = Object.keys(query).reduce(function(obj, key) {
      if (!key) return obj
      obj[encodeRfc3986Full(key)] = !Array.isArray(query[key]) ? query[key] :
        (firstValOnly ? query[key][0] : query[key])
      return obj
    }, {})
    var encodedQueryPieces = []
    Object.keys(reducedQuery).sort().forEach(function(key) {
      if (!Array.isArray(reducedQuery[key])) {
        encodedQueryPieces.push(key + '=' + encodeRfc3986Full(reducedQuery[key]))
      } else {
        reducedQuery[key].map(encodeRfc3986Full).sort()
          .forEach(function(val) { encodedQueryPieces.push(key + '=' + val) })
      }
    })
    queryStr = encodedQueryPieces.join('&')
  }
  if (pathStr !== '/') {
    if (normalizePath) pathStr = pathStr.replace(/\/{2,}/g, '/')
    pathStr = pathStr.split('/').reduce(function(path, piece) {
      if (normalizePath && piece === '..') {
        path.pop()
      } else if (!normalizePath || piece !== '.') {
        if (decodePath) piece = decodeURIComponent(piece.replace(/\+/g, ' '))
        path.push(encodeRfc3986Full(piece))
      }
      return path
    }, []).join('/')
    if (pathStr[0] !== '/') pathStr = '/' + pathStr
    if (decodeSlashesInPath) pathStr = pathStr.replace(/%2F/g, '/')
  }

  return [
    this.request.method || 'GET',
    pathStr,
    queryStr,
    this.canonicalHeaders() + '\n',
    this.signedHeaders(),
    bodyHash,
  ].join('\n')
}

RequestSigner.prototype.canonicalHeaders = function() {
  var headers = this.request.headers
  function trimAll(header) {
    return header.toString().trim().replace(/\s+/g, ' ')
  }
  return Object.keys(headers)
    .filter(function(key) { return HEADERS_TO_IGNORE[key.toLowerCase()] == null })
    .sort(function(a, b) { return a.toLowerCase() < b.toLowerCase() ? -1 : 1 })
    .map(function(key) { return key.toLowerCase() + ':' + trimAll(headers[key]) })
    .join('\n')
}

RequestSigner.prototype.signedHeaders = function() {
  return Object.keys(this.request.headers)
    .map(function(key) { return key.toLowerCase() })
    .filter(function(key) { return HEADERS_TO_IGNORE[key] == null })
    .sort()
    .join(';')
}

RequestSigner.prototype.credentialString = function() {
  return [
    this.getDate(),
    this.region,
    this.service,
    'aws4_request',
  ].join('/')
}

RequestSigner.prototype.defaultCredentials = function() {
  var env = process.env
  return {
    accessKeyId: env.AWS_ACCESS_KEY_ID || env.AWS_ACCESS_KEY,
    secretAccessKey: env.AWS_SECRET_ACCESS_KEY || env.AWS_SECRET_KEY,
    sessionToken: env.AWS_SESSION_TOKEN,
  }
}

RequestSigner.prototype.parsePath = function() {
  var path = this.request.path || '/'

  // S3 doesn't always encode characters > 127 correctly and
  // all services don't encode characters > 255 correctly
  // So if there are non-reserved chars (and it's not already all % encoded), just encode them all
  if (/[^0-9A-Za-z;,/?:@&=+$\-_.!~*'()#%]/.test(path)) {
    path = encodeURI(decodeURI(path))
  }

  var queryIx = path.indexOf('?'),
      query = null

  if (queryIx >= 0) {
    query = querystring.parse(path.slice(queryIx + 1))
    path = path.slice(0, queryIx)
  }

  this.parsedPath = {
    path: path,
    query: query,
  }
}

RequestSigner.prototype.formatPath = function() {
  var path = this.parsedPath.path,
      query = this.parsedPath.query

  if (!query) return path

  // Services don't support empty query string keys
  if (query[''] != null) delete query['']

  return path + '?' + encodeRfc3986(querystring.stringify(query))
}

aws4.RequestSigner = RequestSigner

aws4.sign = function(request, credentials) {
  return new RequestSigner(request, credentials).sign()
}


/***/ }),
/* 104 */
/***/ (function(module, exports) {

module.exports = require("querystring");

/***/ }),
/* 105 */
/***/ (function(module, exports) {

module.exports = function(size) {
  return new LruCache(size)
}

function LruCache(size) {
  this.capacity = size | 0
  this.map = Object.create(null)
  this.list = new DoublyLinkedList()
}

LruCache.prototype.get = function(key) {
  var node = this.map[key]
  if (node == null) return undefined
  this.used(node)
  return node.val
}

LruCache.prototype.set = function(key, val) {
  var node = this.map[key]
  if (node != null) {
    node.val = val
  } else {
    if (!this.capacity) this.prune()
    if (!this.capacity) return false
    node = new DoublyLinkedNode(key, val)
    this.map[key] = node
    this.capacity--
  }
  this.used(node)
  return true
}

LruCache.prototype.used = function(node) {
  this.list.moveToFront(node)
}

LruCache.prototype.prune = function() {
  var node = this.list.pop()
  if (node != null) {
    delete this.map[node.key]
    this.capacity++
  }
}


function DoublyLinkedList() {
  this.firstNode = null
  this.lastNode = null
}

DoublyLinkedList.prototype.moveToFront = function(node) {
  if (this.firstNode == node) return

  this.remove(node)

  if (this.firstNode == null) {
    this.firstNode = node
    this.lastNode = node
    node.prev = null
    node.next = null
  } else {
    node.prev = null
    node.next = this.firstNode
    node.next.prev = node
    this.firstNode = node
  }
}

DoublyLinkedList.prototype.pop = function() {
  var lastNode = this.lastNode
  if (lastNode != null) {
    this.remove(lastNode)
  }
  return lastNode
}

DoublyLinkedList.prototype.remove = function(node) {
  if (this.firstNode == node) {
    this.firstNode = node.next
  } else if (node.prev != null) {
    node.prev.next = node.next
  }
  if (this.lastNode == node) {
    this.lastNode = node.prev
  } else if (node.next != null) {
    node.next.prev = node.prev
  }
}


function DoublyLinkedNode(key, val) {
  this.key = key
  this.val = val
  this.prev = null
  this.next = null
}


/***/ }),
/* 106 */
/***/ (function(module, exports, __webpack_require__) {

// Copyright 2015 Joyent, Inc.

var parser = __webpack_require__(107);
var signer = __webpack_require__(149);
var verify = __webpack_require__(156);
var utils = __webpack_require__(110);



///--- API

module.exports = {

  parse: parser.parseRequest,
  parseRequest: parser.parseRequest,

  sign: signer.signRequest,
  signRequest: signer.signRequest,
  createSigner: signer.createSigner,
  isSigner: signer.isSigner,

  sshKeyToPEM: utils.sshKeyToPEM,
  sshKeyFingerprint: utils.fingerprint,
  pemToRsaSSHKey: utils.pemToRsaSSHKey,

  verify: verify.verifySignature,
  verifySignature: verify.verifySignature,
  verifyHMAC: verify.verifyHMAC
};


/***/ }),
/* 107 */
/***/ (function(module, exports, __webpack_require__) {

// Copyright 2012 Joyent, Inc.  All rights reserved.

var assert = __webpack_require__(108);
var util = __webpack_require__(9);
var utils = __webpack_require__(110);



///--- Globals

var HASH_ALGOS = utils.HASH_ALGOS;
var PK_ALGOS = utils.PK_ALGOS;
var HttpSignatureError = utils.HttpSignatureError;
var InvalidAlgorithmError = utils.InvalidAlgorithmError;
var validateAlgorithm = utils.validateAlgorithm;

var State = {
  New: 0,
  Params: 1
};

var ParamsState = {
  Name: 0,
  Quote: 1,
  Value: 2,
  Comma: 3
};


///--- Specific Errors


function ExpiredRequestError(message) {
  HttpSignatureError.call(this, message, ExpiredRequestError);
}
util.inherits(ExpiredRequestError, HttpSignatureError);


function InvalidHeaderError(message) {
  HttpSignatureError.call(this, message, InvalidHeaderError);
}
util.inherits(InvalidHeaderError, HttpSignatureError);


function InvalidParamsError(message) {
  HttpSignatureError.call(this, message, InvalidParamsError);
}
util.inherits(InvalidParamsError, HttpSignatureError);


function MissingHeaderError(message) {
  HttpSignatureError.call(this, message, MissingHeaderError);
}
util.inherits(MissingHeaderError, HttpSignatureError);

function StrictParsingError(message) {
  HttpSignatureError.call(this, message, StrictParsingError);
}
util.inherits(StrictParsingError, HttpSignatureError);

///--- Exported API

module.exports = {

  /**
   * Parses the 'Authorization' header out of an http.ServerRequest object.
   *
   * Note that this API will fully validate the Authorization header, and throw
   * on any error.  It will not however check the signature, or the keyId format
   * as those are specific to your environment.  You can use the options object
   * to pass in extra constraints.
   *
   * As a response object you can expect this:
   *
   *     {
   *       "scheme": "Signature",
   *       "params": {
   *         "keyId": "foo",
   *         "algorithm": "rsa-sha256",
   *         "headers": [
   *           "date" or "x-date",
   *           "digest"
   *         ],
   *         "signature": "base64"
   *       },
   *       "signingString": "ready to be passed to crypto.verify()"
   *     }
   *
   * @param {Object} request an http.ServerRequest.
   * @param {Object} options an optional options object with:
   *                   - clockSkew: allowed clock skew in seconds (default 300).
   *                   - headers: required header names (def: date or x-date)
   *                   - algorithms: algorithms to support (default: all).
   *                   - strict: should enforce latest spec parsing
   *                             (default: false).
   * @return {Object} parsed out object (see above).
   * @throws {TypeError} on invalid input.
   * @throws {InvalidHeaderError} on an invalid Authorization header error.
   * @throws {InvalidParamsError} if the params in the scheme are invalid.
   * @throws {MissingHeaderError} if the params indicate a header not present,
   *                              either in the request headers from the params,
   *                              or not in the params from a required header
   *                              in options.
   * @throws {StrictParsingError} if old attributes are used in strict parsing
   *                              mode.
   * @throws {ExpiredRequestError} if the value of date or x-date exceeds skew.
   */
  parseRequest: function parseRequest(request, options) {
    assert.object(request, 'request');
    assert.object(request.headers, 'request.headers');
    if (options === undefined) {
      options = {};
    }
    if (options.headers === undefined) {
      options.headers = [request.headers['x-date'] ? 'x-date' : 'date'];
    }
    assert.object(options, 'options');
    assert.arrayOfString(options.headers, 'options.headers');
    assert.optionalFinite(options.clockSkew, 'options.clockSkew');

    var authzHeaderName = options.authorizationHeaderName || 'authorization';

    if (!request.headers[authzHeaderName]) {
      throw new MissingHeaderError('no ' + authzHeaderName + ' header ' +
                                   'present in the request');
    }

    options.clockSkew = options.clockSkew || 300;


    var i = 0;
    var state = State.New;
    var substate = ParamsState.Name;
    var tmpName = '';
    var tmpValue = '';

    var parsed = {
      scheme: '',
      params: {},
      signingString: ''
    };

    var authz = request.headers[authzHeaderName];
    for (i = 0; i < authz.length; i++) {
      var c = authz.charAt(i);

      switch (Number(state)) {

      case State.New:
        if (c !== ' ') parsed.scheme += c;
        else state = State.Params;
        break;