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A simple caching strategy for Node REST APIs, Part 1

Vignesh M on March 03, 2019

Hello World, this is the beginning of 2 Part Series on "How to make your REST APIs blazing fast 🚀". These are from my personal experiences and from...

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José María CL • May 24 '23

Thanks!

I will leave my implementation to help others to figure out how to implement this approach

// get-mydata-controller.ts
export const getMyDataController = async (req, res, next) => {
  try {
    const { id } = req.params;
    const myDataRepository: MyDataRepository = new PrismaMyDataRepository();
    const myData = await getMyData(
      id,
      myDataRepository
    );

    res.locals.data = myData; // make the result accesible to the middlewares

    next(); // allow the next middleware to handle the response data
  } catch (err) {
    res
      .status(500)
      .json({ data: null, error: err.message });
  }
};

// response-handler.ts
export function responseHandler(message = "Data successfully fetched") {
  return (req, res) => {
    res
      .status(200)
      .json({ data: res.locals.data, message });
  }
}

// routes.ts
router.get(
  "/:id/my-data",
  cacheLayer.get,
  getMyDataController,
  cacheLayer.set,
  responseHandler("My Data successfully fetched")
);

Sven Varkel • Oct 12 '19

It seems that you're using URL as cache key, right? Things to be considered:

are the URL-s public? I.e circumstances changes when the URL-s are behind authentication because then you cannot send back the same responses to all users etc.
do all the parameters come in via URL? Are there any headers or anything that may differ between requests? Should these be considered?

What's your cache backend?

Vignesh M • Oct 12 '19

Both of these considerations depend upon one's own project and what routes they want to cache. This example works best for data that only dependents on the URL and not any context like current user.

Gijo Varghese • Mar 5 '19

I wrote a similar one but saving data in Cloudflare edge servers coffeencoding.com/how-i-used-cloud...

Nikos Kanakis • Mar 4 '19

Awesome Post 🏆

Nguyễn Nam Thắng • Sep 18 '19

Can you explain the processQuery, responseHandler fuction for me.

Vignesh M • Sep 18 '19

Hey, processQuery & responseHandler are not anything related to caching or have anything to do with this artcle. They are just examples of common middlewares.

In our app, processQuery transforms some of our url query params, does some checks if they are valid.

responseHandler just converts the response data to json and returns a 200 status.
This may not be everyone's usecase.