request-digest.es6.js

'use strict';
import requestUrl from 'request';
import {createHash} from 'crypto';
import _ from 'lodash';
import Bluebird from 'bluebird';

class HTTPDigest {
    constructor(username, password) {
        this.nc = 0;
        this.username = username;
        this.password = password;
    }

    requestAsync(options) {
        return new Bluebird((resolve, reject) => {
            this.request(options, (error, response, body) => {
                if (error) {
                    return reject(error);
                }

                return resolve({ response, body });
            });
        });
    }

    request(options, callback) {
        let port = options.port ? options.port : 80;

        options.url = `${options.host}:${port}${options.path}`;
        return requestUrl(options, (error, res) => this._handleResponse(options, res, callback));
    }

    _handleResponse(options, res, callback) {
        if (!res) {
          return callback(new Error('Bad request, answer is empty'));
        }
        if (res.statusCode === 200) {
            return callback(null, res, res.body);
        }
        if (typeof res.caseless.dict['www-authenticate'] !== 'string' || res.caseless.dict['www-authenticate'] === '') {
            return callback(new Error('Bad request, www-authenticate field is malformed'));
        }

        let challenge = this._parseDigestResponse(res.caseless.dict['www-authenticate']);
        let ha1 = createHash('md5');
        ha1.update([this.username, challenge.realm, this.password].join(':'));
        let ha2 = createHash('md5');
        ha2.update([options.method, options.path].join(':'));

        let {nc, cnonce} = this._generateCNONCE(challenge.qop);

        // Generate response hash
        let response = createHash('md5');
        let responseParams = [
            ha1.digest('hex'),
            challenge.nonce
        ];

        if (cnonce) {
            responseParams.push(nc);
            responseParams.push(cnonce);
        }

        responseParams.push(challenge.qop);
        responseParams.push(ha2.digest('hex'));
        response.update(responseParams.join(':'));

        // Setup response parameters
        let authParams = {
            username: this.username,
            realm: challenge.realm,
            nonce: challenge.nonce,
            uri: options.path,
            qop: challenge.qop,
            opaque: challenge.opaque,
            response: response.digest('hex')
        };

        authParams = this._omitNull(authParams);

        if (cnonce) {
            authParams.nc = nc;
            authParams.cnonce = cnonce;
        }

        let headers = options.headers || {};
        headers.Authorization = this._compileParams(authParams);
        options.headers = headers;

        return requestUrl(options, (error, response, body) => {
            if (response.statusCode >= 400) {
                let errorMessage = {
                    statusCode: response.statusCode,
                    response,
                    body
                };

                return callback(errorMessage);
            }
            callback(error, response, body);
        });
    }

    _omitNull(data) {
        // _.omit(data, (elt) => {
        //   console.log('elt ' + elt + ' et condition : ' + elt === null);
        //   return elt == null;
        // });
        let newObject = {};
        _.forEach(data, (elt, key) => {
            if (elt != null) {
                newObject[key] = elt;
            }
        });

        return newObject;
    }

    _parseDigestResponse(digestHeader) {
        let prefix = 'Digest ';
        let challenge = digestHeader.substr(digestHeader.indexOf(prefix) + prefix.length);
        let parts = challenge.split(',');
        let length = parts.length;
        let params = {};

        for (let i = 0; i < length; i++) {
            let paramSplitted = this._splitParams(parts[i]);

            if (paramSplitted.length > 2) {
                params[paramSplitted[1]] = paramSplitted[2].replace(/\"/g, '');
            }
        }

        return params;
    }

    _splitParams(paramString) {
        return paramString.match(/^\s*?([a-zA-Z0-0]+)=("(.*)"|MD5|MD5-sess|token|TRUE|FALSE)\s*?$/);
    }

    //
    // ## Parse challenge digest
    //
    _generateCNONCE(qop) {
        let cnonce = false;
        let nc = false;

        if (typeof qop === 'string') {
            let cnonceHash = createHash('md5');

            cnonceHash.update(Math.random().toString(36));
            cnonce = cnonceHash.digest('hex').substr(0, 8);
            nc = this._updateNC();
        }

        return {cnonce: cnonce, nc: nc};
    }

    //
    // ## Compose authorization header
    //

    _compileParams(params) {
        let parts = [];
        for (let i in params) {
            let param = i + '=' + (this._putDoubleQuotes(i) ? '"' : '') + params[i] + (this._putDoubleQuotes(i) ? '"' : '');
            parts.push(param);
        }

        return 'Digest ' + parts.join(',');
    }

    //
    // ## Define if we have to put double quotes or not
    //

    _putDoubleQuotes(i) {
        let excludeList = ['qop', 'nc'];

        return !_.includes(excludeList, i);
    }

    //
    // ## Update and zero pad nc
    //

    _updateNC() {
        let max = 99999999;
        let padding = new Array(8).join('0') + '';
        this.nc = (this.nc > max ? 1 : this.nc + 1);
        let nc = this.nc + '';

        return padding.substr(0, 8 - nc.length) + nc;
    }

}

export default function (username, password) {
    return new HTTPDigest(username, password);
}