cosmos-explorer/public/datafeeds/udf/lib/data-pulse-provider.js
2021-11-21 09:42:01 +08:00

108 lines
5.0 KiB
JavaScript

import { getErrorMessage, logMessage, } from './helpers';
var DataPulseProvider = /** @class */ (function () {
function DataPulseProvider(historyProvider, updateFrequency) {
this._subscribers = {};
this._requestsPending = 0;
this._historyProvider = historyProvider;
setInterval(this._updateData.bind(this), updateFrequency);
}
DataPulseProvider.prototype.subscribeBars = function (symbolInfo, resolution, newDataCallback, listenerGuid) {
if (this._subscribers.hasOwnProperty(listenerGuid)) {
logMessage("DataPulseProvider: already has subscriber with id=" + listenerGuid);
return;
}
this._subscribers[listenerGuid] = {
lastBarTime: null,
listener: newDataCallback,
resolution: resolution,
symbolInfo: symbolInfo,
};
logMessage("DataPulseProvider: subscribed for #" + listenerGuid + " - {" + symbolInfo.name + ", " + resolution + "}");
};
DataPulseProvider.prototype.unsubscribeBars = function (listenerGuid) {
delete this._subscribers[listenerGuid];
logMessage("DataPulseProvider: unsubscribed for #" + listenerGuid);
};
DataPulseProvider.prototype._updateData = function () {
var _this = this;
if (this._requestsPending > 0) {
return;
}
this._requestsPending = 0;
var _loop_1 = function (listenerGuid) {
this_1._requestsPending += 1;
this_1._updateDataForSubscriber(listenerGuid)
.then(function () {
_this._requestsPending -= 1;
logMessage("DataPulseProvider: data for #" + listenerGuid + " updated successfully, pending=" + _this._requestsPending);
})
.catch(function (reason) {
_this._requestsPending -= 1;
logMessage("DataPulseProvider: data for #" + listenerGuid + " updated with error=" + getErrorMessage(reason) + ", pending=" + _this._requestsPending);
});
};
var this_1 = this;
for (var listenerGuid in this._subscribers) {
_loop_1(listenerGuid);
}
};
DataPulseProvider.prototype._updateDataForSubscriber = function (listenerGuid) {
var _this = this;
var subscriptionRecord = this._subscribers[listenerGuid];
var rangeEndTime = parseInt((Date.now() / 1000).toString());
// BEWARE: please note we really need 2 bars, not the only last one
// see the explanation below. `10` is the `large enough` value to work around holidays
var rangeStartTime = rangeEndTime - periodLengthSeconds(subscriptionRecord.resolution, 10);
return this._historyProvider.getBars(subscriptionRecord.symbolInfo, subscriptionRecord.resolution, rangeStartTime, rangeEndTime)
.then(function (result) {
_this._onSubscriberDataReceived(listenerGuid, result);
});
};
DataPulseProvider.prototype._onSubscriberDataReceived = function (listenerGuid, result) {
// means the subscription was cancelled while waiting for data
if (!this._subscribers.hasOwnProperty(listenerGuid)) {
logMessage("DataPulseProvider: Data comes for already unsubscribed subscription #" + listenerGuid);
return;
}
var bars = result.bars;
if (bars.length === 0) {
return;
}
var lastBar = bars[bars.length - 1];
var subscriptionRecord = this._subscribers[listenerGuid];
if (subscriptionRecord.lastBarTime !== null && lastBar.time < subscriptionRecord.lastBarTime) {
return;
}
var isNewBar = subscriptionRecord.lastBarTime !== null && lastBar.time > subscriptionRecord.lastBarTime;
// Pulse updating may miss some trades data (ie, if pulse period = 10 secods and new bar is started 5 seconds later after the last update, the
// old bar's last 5 seconds trades will be lost). Thus, at fist we should broadcast old bar updates when it's ready.
if (isNewBar) {
if (bars.length < 2) {
throw new Error('Not enough bars in history for proper pulse update. Need at least 2.');
}
var previousBar = bars[bars.length - 2];
subscriptionRecord.listener(previousBar);
}
subscriptionRecord.lastBarTime = lastBar.time;
subscriptionRecord.listener(lastBar);
};
return DataPulseProvider;
}());
export { DataPulseProvider };
function periodLengthSeconds(resolution, requiredPeriodsCount) {
var daysCount = 0;
if (resolution === 'D' || resolution === '1D') {
daysCount = requiredPeriodsCount;
}
else if (resolution === 'M' || resolution === '1M') {
daysCount = 31 * requiredPeriodsCount;
}
else if (resolution === 'W' || resolution === '1W') {
daysCount = 7 * requiredPeriodsCount;
}
else {
daysCount = requiredPeriodsCount * parseInt(resolution) / (24 * 60);
}
return daysCount * 24 * 60 * 60;
}