Function cacheResponse

utils/cache.js:145–189

(options = {})

  return { getCachedKeys, addCachedKey, removeModelKey, removeCachedKey, clear };
};

// Initialize cache pool.
const pool = cachePool();

const cachedKeys = cachedKeysStore();

/**
 * Caching middleware for API resposnes.
 * @param {Object} [options] Options to handle individual api cache.
 * @param {number} options.priority The priority of api in cache store.
 * @param {number} options.expiry Cache expiry time of api in minutes.
 * @param {number} options.invalidationKey key to be used while using the invalidateCache middleware.
 * @returns {function} middleware function to help cache api response.
 */
const cacheResponse = (options = {}) => {
  const priority = options.priority || 2;
  const expiry = options.expiry || CACHE_EXPIRY_TIME_MIN;
  const modelKey = options.invalidationKey;
  return async (req, res, next) => {
    try {
      const key = generateCacheKey(req);
      const cacheData = pool.get(key);
      if (cacheData) {
        res.send(cacheData);
      } else {
        /**
         * As we do not have data in our cache we call the next middleware,
         * intercept the response being sent from middleware and store it in cache.
         *  */
        const oldSend = res.send;

        res.send = (body) => {
          if (res.statusCode < 200 || res.statusCode >= 300) {
            res.send = oldSend;
            return res.send(body);
          }

          const cacheValue = {
            priority: priority,
            response: body,
            expiry: new Date().getTime() + minutesToMilliseconds(expiry),
            size: Buffer.byteLength(body),
          };
          pool.set(key, cacheValue);
          if (modelKey) {
            cachedKeys.addCachedKey(modelKey, key);
          }