goginmysqlredisweb-developmentbackendmonolitheducational-project

Forum

GitHub: https://github.com/soondubu137/go-forum

This educational project demonstrates (monolith) web development with Go. This project implements the backend of an online forum.

NOTE

A frontend is not implemented with this project.

Introduction

This is a typical forum project. Users can register and publish posts. Each post belongs to a specific community, users can query for a list of posts (paginated) under a specific community.

There is also a voting mechanism. Users can vote up or down on a specific post, and this will affect the "score" of a post. Time also affect the "score" of a post (newer posts have higher scores). When users query for a list of paginated posts, they can specify the sorting order - by newest or by highest score. Scores are stored in Redis for improved performance.

Project Architecture

This project strictly follows the CSR (controller-service-repository) layered architecture.

TIP

Sometimes "service" is used interchangeably with "logic", and "repository" with "DAO".

Controller: entrance to the underlying service, responsible for handling routes, parameter validation, and redirection.

Service: responsible for handling specific business logic.

Repository: responsible for interacting with the underlying databases.

Technologies & Tools

• In this project, we use the popular web-development framework Gin. The choice of framework is certainly not definitive,

  Be an engineer, not a frameworker.

• Database: MySQL. In this project, we simply use sqlx to write pre-compiled SQL statements to do CRUD, although we can also use GORM to simplify CRUD operations.

• Votes caching: Redis.

• Distributed ID generation: snowflake is a popular distributed ID generation algorithm. It ensures global uniqueness and monotonicity.

• Authentication: JWT (JWT generation: jwt-go).

• Logging: Zap.

• Config management: Viper.

• API testing: Bruno.

Features

• Users

  • JWT

    User authentication is done with single-token JWT (i.e. only authentication token, no refresh token). JWT authentication is implemented as a middleware in Gin, intercepting all auth-required requests. If JWT authentication is successful, the user ID will be injected into the Gin context. See middleware/auth.go for details.

  • Salted password hashing

    Password hashing alone is not sufficient due to its susceptibility to dictionary attack. Salted password hashing increases the brute-force attack's time complexity from $O(D+n)$ to $O(D\cdot n)$, where $D$ is the dictionary size and $n$ is the number of the compromised password hashes.

• Posts

  • CRUD

    Create a post. Query for a list of posts (paginated) under a specific community. When querying for posts, users can specify the order in which the list of posts are returned. Imagine there is a button on the frontend, you can toggle it between "by newest" and "by hottest". I implemented a simple scoring system for the posts, both voting and time can affect the score of a post, which then affects how "hot" a post is.

• Communities

  • CRUD

    Create a community. Query for a list of communities (paginated).

• Voting

  • There are two ZSETs in Redis: post::time where KV-pairs contain post ID and creation time, and post::score where KV-pairs contain post ID and score. In addition, for each post, there is a ZSET keeping track of the voting status. When users create a post or vote for a post, the ZSETs are updated accordingly to ensure the scores are always up-to-date. This functionality is implemented with Redis instead of MySQL to improve performance.

• Engineering

  • Graceful shutdown.
  • Centralized response management.
  • Centralized error management.

Learning Outcomes

Through this project, I

• gained practical experience with Go,
• gained familiarity with MySQL and Redis operations,
• gained familiarity with Gin and other popular web-dev components (zap, viper, etc.),
• gained familiarity with CRS architecture,
• accumulated project design and development experience.

Extensions

Here I list some potential extensions to this project.

Extension	Explanation
Refresh Token	Add a refresh token to JWT authentication.
Post Deletion	Allows users to delete a post. However, this is just more CRUD. If you are already familiar with basic CRUD with sqlx, this task is unenlightening.
Comment	Allows users to post comments on others' posts. This may be slightly more interesting than post deletion, but essentially it is still CRUD.

References

1. This project is based on Wenzhou Li's Go web development course.
2. https://textbook.cs161.org/crypto/passwords.html#148-password-hashing-done-right