144 lines
3.4 KiB
JavaScript
144 lines
3.4 KiB
JavaScript
'use strict';
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//var util = require('util');
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//var _ = require('lodash');
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//var log = require('../util/log');
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//var preconditions = require('preconditions').singleton();
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//var request = require('request');
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/*
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This class lets interfaces with BitPay's exchange rate API.
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*/
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var RateService = function(opts) {
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var self = this;
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opts = opts || {};
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self.httprequest = opts.httprequest; // || request;
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self.lodash = opts.lodash;
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self.SAT_TO_BTC = 1 / 1e8;
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self.BTC_TO_SAT = 1e8;
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self.UNAVAILABLE_ERROR = 'Service is not available - check for service.isAvailable() or use service.whenAvailable()';
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self.UNSUPPORTED_CURRENCY_ERROR = 'Currency not supported';
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self._isAvailable = false;
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self._rates = {};
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self._alternatives = [];
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self._queued = [];
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self._fetchCurrencies();
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};
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var _instance;
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RateService.singleton = function(opts) {
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if (!_instance) {
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_instance = new RateService(opts);
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}
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return _instance;
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};
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RateService.prototype._fetchCurrencies = function() {
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var self = this;
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var backoffSeconds = 5;
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var updateFrequencySeconds = 5 * 60;
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var rateServiceUrl = 'https://bitpay.com/api/rates';
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var retrieve = function() {
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//log.info('Fetching exchange rates');
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self.httprequest.get(rateServiceUrl).success(function(res) {
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self.lodash.each(res, function(currency) {
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self._rates[currency.code] = currency.rate;
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self._alternatives.push({
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name: currency.name,
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isoCode: currency.code,
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rate: currency.rate
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});
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});
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self._isAvailable = true;
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self.lodash.each(self._queued, function(callback) {
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setTimeout(callback, 1);
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});
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setTimeout(retrieve, updateFrequencySeconds * 1000);
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}).error(function(err) {
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//log.debug('Error fetching exchange rates', err);
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setTimeout(function() {
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backoffSeconds *= 1.5;
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retrieve();
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}, backoffSeconds * 1000);
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return;
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});
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};
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retrieve();
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};
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RateService.prototype.getRate = function(code) {
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return this._rates[code];
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};
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RateService.prototype.getAlternatives = function() {
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return this._alternatives;
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};
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RateService.prototype.isAvailable = function() {
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return this._isAvailable;
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};
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RateService.prototype.whenAvailable = function(callback) {
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if (this.isAvailable()) {
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setTimeout(callback, 1);
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} else {
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this._queued.push(callback);
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}
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};
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RateService.prototype.toFiat = function(satoshis, code) {
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if (!this.isAvailable()) {
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return null;
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}
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return satoshis * this.SAT_TO_BTC * this.getRate(code);
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};
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RateService.prototype.fromFiat = function(amount, code) {
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if (!this.isAvailable()) {
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return null;
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}
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return amount / this.getRate(code) * this.BTC_TO_SAT;
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};
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RateService.prototype.listAlternatives = function(sort) {
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var self = this;
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if (!this.isAvailable()) {
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return [];
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}
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var alternatives = self.lodash.map(this.getAlternatives(), function(item) {
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return {
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name: item.name,
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isoCode: item.isoCode
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}
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});
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if (sort) {
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alternatives.sort(function(a, b) {
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return a.name.toLowerCase() > b.name.toLowerCase() ? 1 : -1;
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});
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}
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return self.lodash.uniq(alternatives, 'isoCode');
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};
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angular.module('copayApp.services').factory('rateService', function($http, lodash) {
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// var cfg = _.extend(config.rates, {
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// httprequest: $http
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// });
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var cfg = {
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httprequest: $http,
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lodash: lodash
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};
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return RateService.singleton(cfg);
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});
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