growwapi/dist/resources/liveFeed.js

NodeJS SDK for Groww trading APIs

import { connectToLiveFeed, generateSubscriptionTopic, liveFeedDecoder, retryStrategy } from '../utils/LiveFeed';
export class LiveFeed {
    constructor() {
        this.connection = null;
        this.subscriptions = new Map();
        this.subscriptionCallbacks = new Map();
        this.retryCount = 0;
    }
    async connect() {
        this.connection = await connectToLiveFeed();
    }
    async disconnect() {
        if (this.connection) {
            await this.connection.stream?.close();
            this.connection = null;
        }
    }
    async subscribe(type, exchangeToken) {
        const subscriptionId = this.connection?.credentials.subscriptionId;
        if (!subscriptionId) {
            console.error('Subscription ID is not available. Please connect first.');
            return undefined;
        }
        const topic = await generateSubscriptionTopic(type, subscriptionId, exchangeToken);
        const natsSubscription = this.connection?.stream?.subscribe(topic);
        if (!natsSubscription) {
            console.error(`Failed to subscribe to topic: ${topic}`);
            return undefined;
        }
        const subscription = {
            natsSubscription, type, exchangeToken,
            consume: (callback) => {
                this.subscriptionCallbacks.set(topic, callback);
                this.consume(natsSubscription, callback);
            },
            unsubscribe: () => {
                this.subscriptionCallbacks.delete(topic);
                this.unsubscribe(natsSubscription, topic);
            }
        };
        this.subscriptions.set(topic, subscription);
        return subscription;
    }
    unsubscribe(subscription, topic) {
        if (this.connection) {
            subscription.unsubscribe();
            this.subscriptions.delete(topic);
        }
    }
    async consume(subscription, callback) {
        retryStrategy(this.connection, this.retryCount, () => this.disconnect(), () => this.reconnect(), async () => {
            for await (const m of subscription) {
                const feedType = this.subscriptions.get(m.subject)?.type;
                const liveFeedData = liveFeedDecoder(feedType, m.data);
                callback(liveFeedData);
            }
        });
    }
    async reconnect() {
        await this.connect();
        this.retryCount = 0;
        for (const subscription of this.subscriptions.values()) {
            const newSubscription = await this.subscribe(subscription.type, subscription.exchangeToken);
            if (newSubscription) {
                const callback = this.subscriptionCallbacks.get(subscription.natsSubscription.getSubject());
                if (callback) {
                    newSubscription.consume(callback);
                }
            }
        }
    }
}