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2026-08-08 06:24:43 +08:00 · 2026-02-12 08:11:37 +00:00
parent 47fa783913
commit b33ef907d4
2029 changed files with 53320 additions and 0 deletions
@@ -0,0 +1,146 @@
+import { LibrarySymbolInfo, ResolutionString, SubscribeBarsCallback } from '../../../charting_library/datafeed-api';
+
+import {
+	getErrorMessage,
+	logMessage,
+} from './helpers';
+import { IDataPulseProvider, IHistoryProvider, GetBarsResult } from './provider-interfaces';
+
+interface DataSubscriber {
+	symbolInfo: LibrarySymbolInfo;
+	resolution: ResolutionString;
+	lastBarTime: number | null;
+	listener: SubscribeBarsCallback;
+}
+
+interface DataSubscribers {
+	[guid: string]: DataSubscriber;
+}
+
+export class DataPulseProvider implements IDataPulseProvider {
+	private readonly _subscribers: DataSubscribers = {};
+	private _requestsPending: number = 0;
+	private readonly _historyProvider: IHistoryProvider;
+
+	public constructor(historyProvider: IHistoryProvider, updateFrequency: number) {
+		this._historyProvider = historyProvider;
+		setInterval(this._updateData.bind(this), updateFrequency);
+	}
+
+	public subscribeBars(symbolInfo: LibrarySymbolInfo, resolution: ResolutionString, newDataCallback: SubscribeBarsCallback, listenerGuid: string): void {
+		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}, ${resolution}}`);
+	}
+
+	public unsubscribeBars(listenerGuid: string): void {
+		delete this._subscribers[listenerGuid];
+		logMessage(`DataPulseProvider: unsubscribed for #${listenerGuid}`);
+	}
+
+	private _updateData(): void {
+		if (this._requestsPending > 0) {
+			return;
+		}
+
+		this._requestsPending = 0;
+		// eslint-disable-next-line guard-for-in
+		for (const listenerGuid in this._subscribers) {
+			this._requestsPending += 1;
+			this._updateDataForSubscriber(listenerGuid)
+				.then(() => {
+					this._requestsPending -= 1;
+					logMessage(`DataPulseProvider: data for #${listenerGuid} updated successfully, pending=${this._requestsPending}`);
+				})
+				.catch((reason?: string | Error) => {
+					this._requestsPending -= 1;
+					logMessage(`DataPulseProvider: data for #${listenerGuid} updated with error=${getErrorMessage(reason)}, pending=${this._requestsPending}`);
+				});
+		}
+	}
+
+	private _updateDataForSubscriber(listenerGuid: string): Promise<void> {
+		const subscriptionRecord = this._subscribers[listenerGuid];
+
+		const rangeEndTime = parseInt((Date.now() / 1000).toString());
+
+		// BEWARE: please note we really need 2 bars, not the only last one
+		// see the explanation below. `10` is the `large enough` value to work around holidays
+		const rangeStartTime = rangeEndTime - periodLengthSeconds(subscriptionRecord.resolution, 10);
+
+		return this._historyProvider.getBars(
+			subscriptionRecord.symbolInfo,
+			subscriptionRecord.resolution,
+			{
+				from: rangeStartTime,
+				to: rangeEndTime,
+				countBack: 2,
+				firstDataRequest: false,
+			})
+			.then((result: GetBarsResult) => {
+				this._onSubscriberDataReceived(listenerGuid, result);
+			});
+	}
+
+	private _onSubscriberDataReceived(listenerGuid: string, result: GetBarsResult): void {
+		// means the subscription was cancelled while waiting for data
+		if (!this._subscribers.hasOwnProperty(listenerGuid)) {
+			logMessage(`DataPulseProvider: Data comes for already unsubscribed subscription #${listenerGuid}`);
+			return;
+		}
+
+		const bars = result.bars;
+		if (bars.length === 0) {
+			return;
+		}
+
+		const lastBar = bars[bars.length - 1];
+		const subscriptionRecord = this._subscribers[listenerGuid];
+
+		if (subscriptionRecord.lastBarTime !== null && lastBar.time < subscriptionRecord.lastBarTime) {
+			return;
+		}
+
+		const 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.');
+			}
+
+			const previousBar = bars[bars.length - 2];
+			subscriptionRecord.listener(previousBar);
+		}
+
+		subscriptionRecord.lastBarTime = lastBar.time;
+		subscriptionRecord.listener(lastBar);
+	}
+}
+
+function periodLengthSeconds(resolution: string, requiredPeriodsCount: number): number {
+	let 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;
+}