The “Like” button serves two primary use cases:

• When a user visits an article, a like button is rendered and displays the total number of likes
• When a user clicks the like button, the count increments by one.

This project is server-side(back-end) of application. To see about the client-side(front-end) go to: https://github.com/fabiobelther/like-feature-project.git

This project is a .Net Core 3.1 implementation of Clean Arch with Domain Driven Design concepts.

The Clean Architecture provides a metodology to be used in coding, in order to facilitate code development, allowing a better maintenance, updates and less dependencies. An important goal of Clean Architecture is to provide to developers a way to organize code encapsulating business logic, but keeps it separate from the delivery mechanism.

• LikeFeatureProject.Api - Solution
  • LikeFeatureProject.Api.Host - Interface Adapters (Where are the Controllers )
  • LikeFeatureProject.Api.Domain - Enterprise Business Rules (Where are the Entities, Constraints and Interfaces)
  • LikeFeatureProject.Api.Service - Application Business Rules
  • LikeFeatureProject.Api.Repository - Data Business Rules
  • LikeFeatureProject.Api.Service.Test - Unit Test for Application Businesse Rules
  • LikeFeatureProject.Api.Service.IntegrationTest - Integration Tests

• Table Article (not implemented)

  • id (primary Key - int)

• Table Like

  • id (primary Key - int)
  • articleId (foreign Key(Table Article) - int)
  • count (int)

To clone this project you need to install Git. To run this project you need to download Visual Studio Code or Visual Studio 2019 and have instaled .net core 3.1 SDK in your operating system.

Go to path and run the command on GitBash terminal

git clone https://github.com/fabiobelther/LikeFeatureProject.Api.git

Go to root of application and run the commands on GitBash terminal

dotnet build;

cd LikeFeatureProject.API.Host; 

dotnet run;

The main page should open automatically. If not, go to: Swagger - LikeFeatureProject.Api

in the root of apllication run the command:

dotnet test

• How can you improve the feature to make it more resilient against abuse/exploitation

  • To avoid abuse or the use of robots to generate a huge amount of likes in an article we could:
    • In the front-end create a variable where we would limit the amount of likes (for example, set a maximum of 3), and after reaching the value disable the like button.
    • We could record the ip from the user in a NoSql database like redis and with that, we would limit the amount per article or time.
    • It was not informed that there would be an option to "dislike" in the business rule. If was possible, this action would inhibit abuse, allowing the app user to like the article just once.

• How can you improve the feature to make it scale to millions of users and perform without issues?

• A million concurrent users clicking the button at the same time

• A million concurrent users requesting the article's like count at the same time

  • The solution was built in microservices, however the relational database can be a bottlenecked, to solve these possible problems we could:
    • Record the current number of likes of the article in a NoSql database like redis, and according to Gets requests they would look directly at it.
    • When making a Post, we would use a Queue as AWS SQS or Rabbit asynchronously, and when making a transaction, it would update the key in the NoSql bank.
    • After that we would make a callback to the Front-end with the new value of likes.

• .Net Core Framework - Free, cross-platform, open-source framework;
• xUnit - Tests
• Clean Arch - Clean Architeture concepts

• Fabio Belther - Initial work - FabioBelther

See also the list of contributors who participated in this project.