graphql-amqp-subscriptions/dist/pubsub.js

GraphQL AMQP Subscriptions

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.AMQPPubSub = void 0;
const debug_1 = __importDefault(require("debug"));
const pubsub_async_iterable_iterator_1 = require("graphql-subscriptions/dist/pubsub-async-iterable-iterator");
const uuid_1 = require("uuid");
const publisher_1 = require("./amqp/publisher");
const subscriber_1 = require("./amqp/subscriber");
const logger = (0, debug_1.default)('AMQPPubSub');
class AMQPPubSub {
    publisher;
    subscriber;
    exchange;
    subscriptionMap;
    subsRefsMap;
    unsubscribeMap;
    currentSubscriptionId;
    constructor(config) {
        this.subscriptionMap = {};
        this.subsRefsMap = {};
        this.unsubscribeMap = {};
        this.currentSubscriptionId = 0;
        // Initialize AMQP Helper
        this.publisher = new publisher_1.AMQPPublisher(config, logger);
        this.subscriber = new subscriber_1.AMQPSubscriber(config, logger);
        this.exchange = {
            name: 'graphql_subscriptions',
            type: 'topic',
            options: {
                durable: false,
                autoDelete: false
            },
            ...config.exchange
        };
        logger('Finished initializing');
    }
    async publish(routingKey, payload, options) {
        logger('Publishing message to exchange "%s" for key "%s" (%j)', this.exchange.name, routingKey, payload);
        return this.publisher.publish(routingKey, payload, options);
    }
    async subscribe(routingKey, onMessage, arguments_, options) {
        const id = this.currentSubscriptionId++;
        if (routingKey === 'fanout') {
            routingKey = (0, uuid_1.v4)();
        }
        logger('Subscribing to "%s" with id: "%s"', routingKey, id);
        this.subscriptionMap[id] = {
            routingKey,
            listener: onMessage
        };
        const references = this.subsRefsMap[routingKey];
        if (references && references.length > 0) {
            const newReferences = [...references, id];
            this.subsRefsMap[routingKey] = newReferences;
            return id;
        }
        this.subsRefsMap[routingKey] = [
            ...(this.subsRefsMap[routingKey] || []),
            id
        ];
        const existingDispose = this.unsubscribeMap[routingKey];
        // Get rid of exisiting subscription while we get a new one.
        const [newDispose] = await Promise.all([
            this.subscriber.subscribe(routingKey, this.onMessage, arguments_, options),
            existingDispose ? existingDispose() : Promise.resolve()
        ]);
        this.unsubscribeMap[routingKey] = newDispose;
        return id;
    }
    async unsubscribe(subId) {
        const sub = this.subscriptionMap[subId];
        if (!sub) {
            throw new Error(`There is no subscription for id "${subId}"`);
        }
        const { routingKey } = sub;
        const references = this.subsRefsMap[routingKey];
        if (!references) {
            throw new Error(`There is no subscription ref for routing key "${routingKey}", id "${subId}"`);
        }
        logger('Unsubscribing from "%s" with id: "%s"', routingKey, subId);
        if (references.length === 1) {
            delete this.subscriptionMap[subId];
            return this.unsubscribeForKey(routingKey);
        }
        const index = references.indexOf(subId);
        const newReferences = index === -1
            ? references
            : [...references.slice(0, index), ...references.slice(index + 1)];
        this.subsRefsMap[routingKey] = newReferences;
        delete this.subscriptionMap[subId];
    }
    asyncIterableIterator(triggers) {
        return new pubsub_async_iterable_iterator_1.PubSubAsyncIterableIterator(this, triggers);
    }
    onMessage = (routingKey, content, message) => {
        const subscribers = this.subsRefsMap[routingKey];
        // Don't work for nothing...
        if (!subscribers || subscribers.length === 0) {
            this.unsubscribeForKey(routingKey).catch((error) => {
                logger('onMessage unsubscribeForKey error "%j", Routing Key "%s"', error, routingKey);
            });
            return;
        }
        for (const subId of subscribers) {
            this.subscriptionMap[subId].listener(content, message);
        }
    };
    async unsubscribeForKey(routingKey) {
        const dispose = this.unsubscribeMap[routingKey];
        delete this.unsubscribeMap[routingKey];
        delete this.subsRefsMap[routingKey];
        await dispose();
    }
}
exports.AMQPPubSub = AMQPPubSub;
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