Introduction

During the past year, I have conducted several teaching experiments in my spare time, hoping to improve my teaching materials through continuous teaching and gain some insights from student feedback.

When conducting these teaching experiments, I often think about which existing services can reduce my workload. After all, as an engineer, I want to automate some trivial tasks, and the time saved in the long run is considerable.

Half a year ago, I made my first attempt and shared my experience here: Using Github Classroom and Travis CI to Build a Homework Grading System. After having an automated homework grading system, it did save me a lot of trouble.

This time, I want to share an automated sign-in system that I implemented in about one or two days two weeks ago.

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Introduction

Redis is an in-memory key-value database, often used for caching data to reduce the load on the backend database. This article will briefly introduce some of the useful features of Redis and where it can be applied.

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(Original post published at: http://blog.techbridge.cc/2016/04/23/fast-restful-nodejs-api-backend/)

Introduction

Some websites today use the Single Page Application approach, where the backend only provides APIs for the frontend to fetch data, achieving complete separation of the frontend and backend. There are many choices for the frontend, you can use Angular, Ember.js, or React + Redux. As for the backend API, it must conform to a fixed format to make it easier for frontend developers to fetch data. And this “fixed format” is most commonly known as our focus today: RESTful.

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Recently, there was an incident where our server was attacked by a large number of requests. Unfortunately, the server was hosting a forum service. Assuming that the attack point was the forum homepage, each request would query the database and there were a lot of joins. Some of the instructions were POST, which would update the database. This caused the database to lock up and the CPU to skyrocket, leading to a crash.

If the forum was self-written, we could add a cache like Redis between the database and application. However, this forum system is someone else’s and we cannot modify it.

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