cacheable

cache.js

import {HttpResponse} from "../utils";
import {get} from "lodash";

// compute cache key
function getCacheKey(req, options) {
    if (typeof options.hashFn === 'function') {
        return options.hashFn(req);
    }
    const {body, query} = req;
    const keys = [];

    options.body.forEach(key => {
        keys.push(get(body, key));
    });

    options.query.forEach(key => {
        keys.push(get(query, key));
    });

    options.headers.forEach(key => {
        keys.push(req.get(key));
    });

    options.params.forEach(key => {
        keys.push(req.params[key]);
    });

    return keys.join(':');
}

/**
 * @param {function} hashFn
 * @param {[string]} body
 * @param {[string]} query
 * @param {[string]} headers
 * @param {[string]} params
 */
export function Cacheable({
                              hashFn,
                              body = [],
                              query = [],
                              headers = [],
                              params = [],
                          } = {}) {
    return target => {
        const original = target.descriptor.value;
        target.descriptor.value = async function (req, res) {
            const key = await getCacheKey(req, {body, query, headers, hashFn, params});
            const cached = await cache.get(key);
            if (cached) {
                return new HttpResponse(cached, 200, {
                    'x-cache': 'hit',
                });
            }

            const result = await original.apply(this, [req, res]);
            await cache.set(key, result);
            return new HttpResponse(result, 200, {
                'x-cache': 'miss',
            });
        };
        return target;
    };
}