@siva-sub/mcp-public-transport/dist/esm/services/cache.js

A Model Context Protocol server for Singapore transport data with real-time information and routing

import NodeCache from 'node-cache';
import { logger } from '../utils/logger.js';
export class CacheService {
    cache;
    hitCount = 0;
    missCount = 0;
    constructor(defaultTtl = 300) {
        this.cache = new NodeCache({
            stdTTL: defaultTtl,
            checkperiod: 60,
            useClones: false,
            deleteOnExpire: true,
        });
        this.cache.on('expired', (key) => {
            logger.debug(`Cache key expired: ${key}`);
        });
        this.cache.on('del', (key) => {
            logger.debug(`Cache key deleted: ${key}`);
        });
    }
    async getOrSet(key, fetchFn, ttl) {
        const cached = this.cache.get(key);
        if (cached !== undefined) {
            this.hitCount++;
            logger.debug(`Cache hit: ${key}`);
            return cached;
        }
        this.missCount++;
        logger.debug(`Cache miss: ${key}`);
        try {
            const data = await fetchFn();
            this.cache.set(key, data, ttl || 300);
            logger.debug(`Cache set: ${key} (TTL: ${ttl || 'default'})`);
            return data;
        }
        catch (error) {
            logger.error(`Failed to fetch data for cache key: ${key}`, error);
            throw error;
        }
    }
    get(key) {
        const value = this.cache.get(key);
        if (value !== undefined) {
            this.hitCount++;
        }
        else {
            this.missCount++;
        }
        return value;
    }
    set(key, value, ttl) {
        return this.cache.set(key, value, ttl || 300);
    }
    del(key) {
        return this.cache.del(key);
    }
    flush() {
        this.cache.flushAll();
        logger.info('Cache flushed');
    }
    getStats() {
        const cacheStats = this.cache.getStats();
        return {
            ...cacheStats,
            hitRate: this.hitCount / (this.hitCount + this.missCount) || 0,
            hitCount: this.hitCount,
            missCount: this.missCount,
        };
    }
}