blocktrail / blocktrail-sdk-nodejs

var blocktrail = require('./blocktrail'),

    _ = require("lodash"),

    url = require('url'),

    qs = require('querystring'),

    q = require('q'),

    createHash = require('create-hash'),

    superagent = require('superagent'),

    superagentHttpSignature = require('superagent-http-signature/index-hmac-only');

var debug = require('debug')('blocktrail-sdk:request');

var isNodeJS = !process.browser;

var noop = function() {};

/**

 * Helper for doing HTTP requests

 *

 * @param options       object{

 *                          host: '',

 *                          endpoint: '', // base url for .request

 *                          auth: null || 'http-signature',

 *                          apiKey: 'API_KEY',

 *                          apiSecret: 'API_SECRET',

 *                          params: {}, // defaults

 *                          headers: {} // defaults

 *                      }

 * @constructor

 */

function Request(options) {

    var self = this;

    self.https = options.https;

    self.host = options.host;

    self.endpoint = options.endpoint;

    self.auth = options.auth;

    self.port = options.port;

    self.apiKey = options.apiKey;

    self.apiSecret = options.apiSecret;

    self.contentMd5 = typeof options.contentMd5 !== "undefined" ? options.contentMd5 : true;

    self.params = _.defaults({}, options.params);

    self.headers = _.defaults({}, options.headers);

}

/**

 * helper to make sure the query string is sorted in lexical order

 *

 * @param params

 * @returns {string}

 */

Request.qs = function(params) {

    var query = [];

    var qsKeys = Object.keys(params);

    qsKeys.sort();

    qsKeys.forEach(function(qsKey) {

        var qsChunk = {};

        qsChunk[qsKey] = params[qsKey];

        query.push(qs.stringify(qsChunk));

    });

    return query.join("&");

};

/**

 * execute request

 *

 * @param method        string      GET|POST|DELETE

 * @param resource      string      URL

 * @param params        object      are added to the querystring

 * @param data          object      is POSTed

 * @param fn

 * @returns q.Promise

 */

Request.prototype.request = function(method, resource, params, data, fn) {

    var self = this;

    self.deferred = q.defer();

    self.callback = fn || noop;

    var endpoint = url.parse(resource, true);

    var query = Request.qs(_.defaults({}, (params || {}), (endpoint.query || {}), (self.params || {})));

    self.path = ''.concat(self.endpoint, endpoint.pathname);

    if (query) {

        self.path = self.path.concat('?', query);

    }

    if (data) {

        self.payload = JSON.stringify(data);

        self.headers['Content-Type'] = 'application/json';

    } else {

        self.payload = "";

    }

    if (isNodeJS) {

        self.headers['Content-Length'] = self.payload ? self.payload.length : 0;

    }

    if (self.contentMd5 === true) {

        if (method === 'GET' || method === 'DELETE') {

            self.headers['Content-MD5'] = createHash('md5').update(self.path).digest().toString('hex');

        } else {

            self.headers['Content-MD5'] = createHash('md5').update(self.payload).digest().toString('hex');

        }

    }

    debug('%s %s %s', method, self.host, self.path);

    var opts = {

        hostname: self.host,

        path: self.path,

        port: self.port,

        method: method,

        headers: self.headers,

        auth: self.auth,

        agent: false,

        withCredentials: false

    };

    self.performRequest(opts);

    return self.deferred.promise;

};

Request.prototype.performRequest = function(options) {

    var self = this;

    var method = options.method;

    var signHMAC = false;

    if (options.auth === 'http-signature') {

        signHMAC = true;

        delete options.auth;

    }

    var uri = (self.https ? 'https://' : 'http://') + options.hostname + options.path;

    var request = superagent(method, uri);

    if (self.payload && (method === 'DELETE' || method === 'POST' || method === 'PUT' || method === 'PATCH')) {

        request.send(self.payload);

    }

    _.forEach(options.headers, function(value, header) {

        request.set(header, value);

    });

    if (signHMAC) {

        if (!self.apiSecret) {

            var error = new Error("Missing apiSecret! required to sign POST requests!");

            self.deferred.reject(error);

            return self.callback(error);

        }

        request.use(superagentHttpSignature({

            headers: ['(request-target)', 'content-md5'],

            algorithm: 'hmac-sha256',

            key: self.apiSecret,

            keyId: self.apiKey

        }));

    }

    request.end(function(error, res) {

        var body;

        if (error) {

            self.deferred.reject(error);

            return self.callback(error);

        }

        debug('response status code: %s content type: %s', res.status, res.headers['content-type']);

        if (!error && (res.headers['content-type'].indexOf('application/json') >= 0)) {

            try {

                body = JSON.parse(res.text);

            } catch (e) {

                error = e;

            }

        }

        if (!body) {

            body = res.text;

        }

        if (!error && res.status !== 200) {

            error = Request.handleFailure(res.text, res.statusCode);

        }

        if (error) {

            self.deferred.reject(error);

        } else {

            self.deferred.resolve(body);

        }

        return self.callback(error, body);

    });

    return self.deferred;

};

Request.handleFailure = function(body, statusCode) {

    var data, error;

    if (typeof body === "object") {

        data = body;

    } else {

        try {

            data = JSON.parse(body);

    }

    if (data) {

        error = new Error(data.msg ? data.msg : null);

        Object.keys(data).forEach(function(k) {

            if (k !== "msg") {

                error[k] = data[k];

            }

        });

    } else if (body) {

        error = new Error(body);

    } else {

        error = new Error('Unknown Server Error');

    }

    if (statusCode) {

        error.statusCode = statusCode;

    }

    return Request.convertError(error);

};

module.exports = Request;