koa-cash.js

const ms = require('ms');
const safeStringify = require('fast-safe-stringify');
const logger = require('../helpers/logger');

module.exports = (client) => ({
  maxAge: ms('1y') / 1000,
  hash: (ctx) => `koa-cash:${ctx.request.url}`,
  setCachedHeader: true,
  async get(key) {
    let [buffer, data] = await Promise.all([
      client.getBuffer(`buffer:${key}`),
      client.get(key)
    ]);
    if (!data) return;
    try {
      data = JSON.parse(data);
      if (buffer) data.body = buffer;
      return data;
    } catch (err) {
      logger.error(err);
    }
  },
  async set(key, value, maxAge) {
    //
    // we must detect if the `value.body` is a buffer
    // and if so, we need to store it in redis as a buffer
    // and fetch it as a buffer using `getBuffer` as well
    //
    if (Buffer.isBuffer(value.body)) {
      const { body, ...data } = value;
      await client.mset(
        new Map([
          [`buffer:${key}`, body, ...(maxAge > 0 ? ['EX', maxAge] : [])],
          [key, safeStringify(data), ...(maxAge > 0 ? ['EX', maxAge] : [])]
        ])
      );
    } else {
      if (maxAge <= 0) return client.set(key, safeStringify(value));
      client.set(key, safeStringify(value), 'EX', maxAge);
    }
  }
});