// Copyright 2012 Joyent, Inc. All rights reserved.
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var assert = require('assert-plus');
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var util = require('util');
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var utils = require('./utils');
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///--- Globals
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var HASH_ALGOS = utils.HASH_ALGOS;
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var PK_ALGOS = utils.PK_ALGOS;
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var HttpSignatureError = utils.HttpSignatureError;
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var InvalidAlgorithmError = utils.InvalidAlgorithmError;
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var validateAlgorithm = utils.validateAlgorithm;
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var State = {
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New: 0,
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Params: 1
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};
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var ParamsState = {
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Name: 0,
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Quote: 1,
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Value: 2,
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Comma: 3
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};
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///--- Specific Errors
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function ExpiredRequestError(message) {
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HttpSignatureError.call(this, message, ExpiredRequestError);
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}
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util.inherits(ExpiredRequestError, HttpSignatureError);
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function InvalidHeaderError(message) {
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HttpSignatureError.call(this, message, InvalidHeaderError);
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}
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util.inherits(InvalidHeaderError, HttpSignatureError);
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function InvalidParamsError(message) {
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HttpSignatureError.call(this, message, InvalidParamsError);
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}
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util.inherits(InvalidParamsError, HttpSignatureError);
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function MissingHeaderError(message) {
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HttpSignatureError.call(this, message, MissingHeaderError);
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}
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util.inherits(MissingHeaderError, HttpSignatureError);
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function StrictParsingError(message) {
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HttpSignatureError.call(this, message, StrictParsingError);
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}
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util.inherits(StrictParsingError, HttpSignatureError);
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///--- Exported API
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module.exports = {
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/**
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* Parses the 'Authorization' header out of an http.ServerRequest object.
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*
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* Note that this API will fully validate the Authorization header, and throw
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* on any error. It will not however check the signature, or the keyId format
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* as those are specific to your environment. You can use the options object
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* to pass in extra constraints.
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*
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* As a response object you can expect this:
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*
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* {
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* "scheme": "Signature",
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* "params": {
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* "keyId": "foo",
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* "algorithm": "rsa-sha256",
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* "headers": [
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* "date" or "x-date",
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* "digest"
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* ],
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* "signature": "base64"
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* },
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* "signingString": "ready to be passed to crypto.verify()"
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* }
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*
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* @param {Object} request an http.ServerRequest.
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* @param {Object} options an optional options object with:
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* - clockSkew: allowed clock skew in seconds (default 300).
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* - headers: required header names (def: date or x-date)
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* - algorithms: algorithms to support (default: all).
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* - strict: should enforce latest spec parsing
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* (default: false).
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* @return {Object} parsed out object (see above).
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* @throws {TypeError} on invalid input.
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* @throws {InvalidHeaderError} on an invalid Authorization header error.
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* @throws {InvalidParamsError} if the params in the scheme are invalid.
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* @throws {MissingHeaderError} if the params indicate a header not present,
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* either in the request headers from the params,
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* or not in the params from a required header
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* in options.
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* @throws {StrictParsingError} if old attributes are used in strict parsing
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* mode.
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* @throws {ExpiredRequestError} if the value of date or x-date exceeds skew.
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*/
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parseRequest: function parseRequest(request, options) {
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assert.object(request, 'request');
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assert.object(request.headers, 'request.headers');
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if (options === undefined) {
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options = {};
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}
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if (options.headers === undefined) {
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options.headers = [request.headers['x-date'] ? 'x-date' : 'date'];
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}
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assert.object(options, 'options');
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assert.arrayOfString(options.headers, 'options.headers');
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assert.optionalFinite(options.clockSkew, 'options.clockSkew');
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var authzHeaderName = options.authorizationHeaderName || 'authorization';
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if (!request.headers[authzHeaderName]) {
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throw new MissingHeaderError('no ' + authzHeaderName + ' header ' +
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'present in the request');
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}
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options.clockSkew = options.clockSkew || 300;
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var i = 0;
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var state = State.New;
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var substate = ParamsState.Name;
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var tmpName = '';
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var tmpValue = '';
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var parsed = {
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scheme: '',
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params: {},
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signingString: ''
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};
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var authz = request.headers[authzHeaderName];
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for (i = 0; i < authz.length; i++) {
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var c = authz.charAt(i);
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switch (Number(state)) {
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case State.New:
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if (c !== ' ') parsed.scheme += c;
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else state = State.Params;
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break;
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case State.Params:
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switch (Number(substate)) {
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case ParamsState.Name:
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var code = c.charCodeAt(0);
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// restricted name of A-Z / a-z
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if ((code >= 0x41 && code <= 0x5a) || // A-Z
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(code >= 0x61 && code <= 0x7a)) { // a-z
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tmpName += c;
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} else if (c === '=') {
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if (tmpName.length === 0)
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throw new InvalidHeaderError('bad param format');
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substate = ParamsState.Quote;
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} else {
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throw new InvalidHeaderError('bad param format');
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}
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break;
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case ParamsState.Quote:
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if (c === '"') {
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tmpValue = '';
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substate = ParamsState.Value;
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} else {
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throw new InvalidHeaderError('bad param format');
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}
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break;
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case ParamsState.Value:
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if (c === '"') {
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parsed.params[tmpName] = tmpValue;
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substate = ParamsState.Comma;
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} else {
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tmpValue += c;
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}
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break;
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case ParamsState.Comma:
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if (c === ',') {
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tmpName = '';
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substate = ParamsState.Name;
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} else {
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throw new InvalidHeaderError('bad param format');
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}
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break;
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default:
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throw new Error('Invalid substate');
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}
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break;
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default:
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throw new Error('Invalid substate');
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}
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}
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if (!parsed.params.headers || parsed.params.headers === '') {
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if (request.headers['x-date']) {
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parsed.params.headers = ['x-date'];
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} else {
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parsed.params.headers = ['date'];
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}
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} else {
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parsed.params.headers = parsed.params.headers.split(' ');
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}
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// Minimally validate the parsed object
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if (!parsed.scheme || parsed.scheme !== 'Signature')
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throw new InvalidHeaderError('scheme was not "Signature"');
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if (!parsed.params.keyId)
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throw new InvalidHeaderError('keyId was not specified');
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if (!parsed.params.algorithm)
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throw new InvalidHeaderError('algorithm was not specified');
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if (!parsed.params.signature)
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throw new InvalidHeaderError('signature was not specified');
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// Check the algorithm against the official list
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parsed.params.algorithm = parsed.params.algorithm.toLowerCase();
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try {
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validateAlgorithm(parsed.params.algorithm);
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} catch (e) {
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if (e instanceof InvalidAlgorithmError)
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throw (new InvalidParamsError(parsed.params.algorithm + ' is not ' +
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'supported'));
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else
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throw (e);
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}
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// Build the signingString
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for (i = 0; i < parsed.params.headers.length; i++) {
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var h = parsed.params.headers[i].toLowerCase();
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parsed.params.headers[i] = h;
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if (h === 'request-line') {
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if (!options.strict) {
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/*
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* We allow headers from the older spec drafts if strict parsing isn't
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* specified in options.
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*/
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parsed.signingString +=
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request.method + ' ' + request.url + ' HTTP/' + request.httpVersion;
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} else {
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/* Strict parsing doesn't allow older draft headers. */
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throw (new StrictParsingError('request-line is not a valid header ' +
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'with strict parsing enabled.'));
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}
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} else if (h === '(request-target)') {
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parsed.signingString +=
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'(request-target): ' + request.method.toLowerCase() + ' ' +
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request.url;
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} else {
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var value = request.headers[h];
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if (value === undefined)
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throw new MissingHeaderError(h + ' was not in the request');
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parsed.signingString += h + ': ' + value;
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}
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if ((i + 1) < parsed.params.headers.length)
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parsed.signingString += '\n';
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}
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// Check against the constraints
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var date;
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if (request.headers.date || request.headers['x-date']) {
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if (request.headers['x-date']) {
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date = new Date(request.headers['x-date']);
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} else {
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date = new Date(request.headers.date);
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}
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var now = new Date();
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var skew = Math.abs(now.getTime() - date.getTime());
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if (skew > options.clockSkew * 1000) {
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throw new ExpiredRequestError('clock skew of ' +
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(skew / 1000) +
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's was greater than ' +
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options.clockSkew + 's');
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}
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}
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options.headers.forEach(function (hdr) {
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// Remember that we already checked any headers in the params
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// were in the request, so if this passes we're good.
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if (parsed.params.headers.indexOf(hdr.toLowerCase()) < 0)
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throw new MissingHeaderError(hdr + ' was not a signed header');
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});
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if (options.algorithms) {
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if (options.algorithms.indexOf(parsed.params.algorithm) === -1)
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throw new InvalidParamsError(parsed.params.algorithm +
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' is not a supported algorithm');
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}
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parsed.algorithm = parsed.params.algorithm.toUpperCase();
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parsed.keyId = parsed.params.keyId;
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return parsed;
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}
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};
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