Cache

The Cache class provides caching capabilities that can take one of two forms: an in-memory cache or a cache backed by a Redis instance.

info

Every integration hosted by Unito has access to a Redis instance which can be found using the environment variable process.env.REDIS_URL.

Methods

static create()

Takes an optional URL pointing to a Redis database. If the URL is provided, a Cache using the target Redis database will be returned, otherwise, the method will return an in-memory cache instead.

getOrFetchValue()

Returns the cached value if present, or calls the provided fetch function to compute the value, cache it for the given time-to-live value (in seconds), and return it to the caller.

getValue()

Returns the cached value, or undefined if absent.

setValue()

Sets the value for the given key, in cache. An optional time-to-live value (in seconds) can be passed, otherwise the value will never expire.

delValue()

Removes the given key and its corresponding value from the cache.

getTtl()

Returns the remaining TTL on the entry (in miliseconds), undefined if the entry does not exist, or 0 if the entry does not expire.

Examples

To make a cache available through your integration code base, create a file named cache.ts.

You can pass a URL pointing to a Redis database to receive a Cache connected to this database;

import { Cache } from '@unito/integration-sdk';

export const cache: Cache = Cache.create(process.env.REDIS_URL);

Or alternatively, you can omit the URL and receive an in-memory cache;

import { Cache } from '@unito/integration-sdk';

export const cache: Cache = Cache.create();

From there, your cache is available to use elsewhere in you codebase, as needed;

import { cache } from './cache.ts';

const cacheKey = 'MyGlobalyUniqueKey_xyz';
const cacheTtl = 300; // 5 mins as an example

export const getItem: GetItemHandler = async context => {
  const response = await cache.getOrFetchValue(cacheKey, cacheTtl, async () => {
    // Actual fetch function to use on cache miss
  });
  // etc.
};