| 8 | * @param {Object} [opt] options for cache pool |
| 9 | * @param {number} opt.maximumSize Maximum size of the cache pool in Megabytes (MB) |
| 10 | */ |
| 11 | const cachePool = (opt = { maximumSize: CACHE_SIZE_MB }) => { |
| 12 | const cacheStore = new Map(); |
| 13 | |
| 14 | let hits = 0; |
| 15 | |
| 16 | /** |
| 17 | * Get an API Response from cacheStore. |
| 18 | * @param {string} key |
| 19 | * @returns {null | object} |
| 20 | */ |
| 21 | const get = (key) => { |
| 22 | const cachedData = cacheStore.get(key); |
| 23 | |
| 24 | if (!cachedData) { |
| 25 | return null; |
| 26 | } |
| 27 | |
| 28 | const isCacheDataExpired = new Date().getTime() > cachedData.expiry; |
| 29 | |
| 30 | // If data is expired remove it from store, time to get a fresh copy. |
| 31 | if (isCacheDataExpired) { |
| 32 | evict(key); |
| 33 | return null; |
| 34 | } |
| 35 | |
| 36 | hits += 1; |
| 37 | try { |
| 38 | return JSON.parse(cachedData.response); |
| 39 | } catch (err) { |
| 40 | logger.error(`Error while parsing cachedData.response ${err}`); |
| 41 | throw err; |
| 42 | } |
| 43 | }; |
| 44 | |
| 45 | /** |
| 46 | * Remove an API Response from cacheStore. |
| 47 | * @param {string} key |
| 48 | * @returns {boolean} |
| 49 | */ |
| 50 | const evict = (key) => { |
| 51 | return cacheStore.delete(key); |
| 52 | }; |
| 53 | |
| 54 | /** |
| 55 | * Add API response to cacheStore. |
| 56 | * @param {string} key |
| 57 | * @param {Object} value Value to be stored inside the cache. |
| 58 | * @param {number} value.priority Priority of the api |
| 59 | * @param {string} value.response Response from controller |
| 60 | * @param {number} value.expiry Expiry time of api |
| 61 | * @param {number} value.size Size of api response in byte |
| 62 | * @returns {number} : statusCode |
| 63 | */ |
| 64 | const set = async (key, value) => { |
| 65 | try { |
| 66 | cacheStore.set(key, value); |
| 67 | return true; |