@gofynd/fdk-extension-javascript/express/storage/sqlite_storage.js

FDK Extension Helper Library

'use strict';

const BaseStorage = require("./base_storage");

/**
 * SQLiteStorage class for handling storage operations with SQLite.
 * Note: This storage is not advisable for production environments.
 * @extends BaseStorage
 */
class SQLiteStorage extends BaseStorage {
    /**
     * Creates an instance of SQLiteStorage.
     * @param {Object} dbClient - The SQLite database client.
     * @param {string} prefixKey - The prefix key for storage keys.
     */
    constructor(dbClient, prefixKey) {
        super(prefixKey);
        this.dbClient = dbClient;
        this.initializeTable();
        this.setupTTLChecker();
        this.ttlCheckerInterval = null;
    }

    /**
     * Initializes the storage table if it does not exist.
     * @returns {Promise<void>}
     */
    async initializeTable() {
        const query = `
            CREATE TABLE IF NOT EXISTS storage (
                key TEXT PRIMARY KEY,
                value TEXT,
                ttl INTEGER
            )`;
        await this.dbClient.run(query);
    }

    /**
     * Sets up a TTL checker to remove expired keys.
     */
    setupTTLChecker() {
        if (!this.ttlCheckerInterval) {
            this.ttlCheckerInterval =
                setInterval(async () => {
                    const now = Math.floor(Date.now() / 1000);
                    const deleteQuery = `DELETE FROM storage WHERE ttl < ? AND ttl IS NOT NULL`;
                    await this.dbClient.run(deleteQuery, [now]);
                }, 10000);
        }
    }

    /**
     * Retrieves a value by key from the storage.
     * @param {string} key - The key to retrieve.
     * @returns {Promise<Object|null>} - The value associated with the key, or null if not found.
     */
    async get(key) {
        const row = await new Promise((resolve, reject) => {
            this.dbClient.get(`SELECT value FROM storage WHERE key = ?`, [this.prefixKey + key], (err, results) => {
                if (err) {
                    reject(err);
                } else {
                    resolve(results);
                }
            });
        });
        return row ? JSON.parse(row.value) : null;
    }

    /**
     * Sets a value by key in the storage.
     * @param {string} key - The key to set.
     * @param {Object} value - The value to set.
     * @returns {Promise<void>}
     */
    async set(key, value) {
        return await this.dbClient.run(
            `INSERT INTO storage (key, value) VALUES (?, ?) 
             ON CONFLICT(key) DO UPDATE SET value = excluded.value`,
            [this.prefixKey + key, JSON.stringify(value)]
        );
    }

    /**
     * Sets a value by key in the storage with an expiration time.
     * @param {string} key - The key to set.
     * @param {Object} value - The value to set.
     * @param {number} ttl - Time to live in seconds.
     * @returns {Promise<void>}
     */
    async setex(key, value, ttl) {
        const expiresAt = Math.floor(Date.now() / 1000) + ttl;
        return await this.dbClient.run(
            `INSERT INTO storage (key, value, ttl) VALUES (?, ?, ?) 
             ON CONFLICT(key) DO UPDATE SET value = excluded.value, ttl = excluded.ttl`,
            [this.prefixKey + key, JSON.stringify(value), expiresAt]
        );
    }

    /**
     * Deletes a value by key from the storage.
     * @param {string} key - The key to delete.
     * @returns {Promise<void>}
     */
    async del(key) {
        return await this.dbClient.run(`DELETE FROM storage WHERE key = ?`, [this.prefixKey + key]);
    }
}

module.exports = SQLiteStorage;