Getting Started with the URL Shortener project

• Overall structure
• Run
• Build and Run
• Functionalities
• Delivery
• Repositories
• Reference Documentation
• Guides

Overall structure

The structure of this project is heavily influenced by the clean architecture:

• A core module where we define the domain entities and the functionalities (also known as uses cases, business rules, etc.). They do not know that this application. has a web interface or that data is stored in relational databases.
• A repositories module that knows how to store domain entities in a relational database.
• A delivery module that knows how to expose in the Web the functionalities.
• An app module that contains the main, the configuration (i.e. it links core, delivery and repositories), and the static assets (i.e. html files, JavaScript files, etc. )

Usually, if you plan to add a new feature, usually:

• You will add a new use case to the core module.
• If required, you will modify the persistence model in the repositories module.
• You will implement a web-oriented solution to expose to clients in the delivery module.

Sometimes, your feature will not be as simple, and it would require:

• To connect a third party (e.g. an external server). In this case you will add a new module named gateway responsible for such task.
• An additional application.
  In this case you can create a new application module (e.g. app2) with the appropriate configuration to run this second server.

Features that require the connection to a third party or having more than a single app will be rewarded.

Run

First you need to install and start the RabbitMQ service:

On windows:

docker pull rabbitmq:3-management
docker run -d -p 15672:15672 -p 5672:5672 --name rabbit-urlshortener rabbitmq:3-management

On linux:

sudo apt install rabbitmq-server
sudo systemctl enable rabbitmq-server
sudo rabbitmq-plugins enable rabbitmq_management

Then access to the RabbitMQ dashboard (http://localhost:15672) and login with "guest" as user and password

The application can be run as follows:

./gradlew :app:bootRun

Build and Run

The uberjar can be built and then run with:

./gradlew build
java -jar app/build/libs/app.jar

Functionalities

The project offers a minimum set of functionalities:

• Create a short URL. See in core the use case CreateShortUrlUseCase and in delivery the REST controller UrlShortenerController.

• Redirect to a URL. See in core the use case RedirectUseCase and in delivery the REST controller UrlShortenerController.

• Log redirects. See in core the use case LogClickUseCase and in delivery the REST controller UrlShortenerController.

• Check URL in black list. See in core the use case BlackListUseCase and in delivery the REST controller UrlShortenerController.

• Create Short URLs from csv file. See in core the use case CreateShortUrlCsvUseCase and in delivery the REST controller UrlShortenerController.

• Get info from request's header. See in core the use case HeadersInfoUseCase and in delivery the REST controller UrlShortenerController.

• Show clicks summary from. See in core the use case InfoSummaryUseCase and in delivery the REST controller UrlShortenerController.

• Return clicks summary from URL. See in core the use case SponsorUseCase and in delivery the REST controller UrlShortenerController.

The objects in the domain are:

• ShortUrl: the minimum information about a short url
• Redirection: the remote URI and the redirection mode
• ShortUrlProperties: a handy way to extend data about a short url
• Click: the minimum data captured when a redirection is logged
• ClickProperties: a handy way to extend data about a click
• CsvResponse: a handy way to extend data about the processed urls from a csv

Delivery

The above functionality is available through a simple API:

• POST /api/link which creates a short URL from data sent by a form.
• POST /api/bulk which creates short URLs from a csv file sent by a form and downloads the resulting csv on a browser.
• GET /tiny-{id} where id identifies the short url, deals with redirects, and logs use (i.e. clicks).
• GET /api/link/{id} which shows the clicks summary of an URL.

In addition, GET / returns the landing page of the system.

Repositories

All the data is stored in a relational database. There are only two tables.

• shorturl that represents short url and encodes in each row ShortUrl related data,
• click that represents clicks and encodes in each row Click related data.

Reference Documentation

For further reference, please consider the following sections:

• Official Gradle documentation
• Spring Boot Gradle Plugin Reference Guide
• Spring Web
• Spring Data JPA

Guides

The following guides illustrate how to use some features concretely:

• Building a RESTful Web Service
• Serving Web Content with Spring MVC
• Building REST services with Spring
• Accessing Data with JPA
• Messaging with RabbitMQ with Spring
• Setup SonarCloud for Gradle (Solo en parte, pues al vincular SonarCloud con tu cuenta de github y el proyecto, el propio SonarCloud tiene una guia de un par de pasos sobre como añadirlo a gradle y al CI)