URL Shortener mini HOWTO.

It is a system for creating a short url for given any url.

Technologies

This application is a Gradle project based on Spring-Boot, H2 database (and Database could be replaced with some other DB you want, using docker image or something else), Liquibase, and other modules (look at the build.gradle to get more details).

Description

This is a web application. You need a browser to work with it. The default URL for the application is http://localhost:8181.

At the first-home page you will see a form, where you have to enter your link ( for example: https://www.microsoft.com/ru-ru/microsoft-365 ) and press Submit button. Then on the second page ( result page ), you will get your link and short link, which is a redirect to your link.

Algorithm

We know that Protocol and domain name in the URL is Case Insensitive. This means that http://www.google.com is the same as HTTP://WWW.GOOGLE.com, but then the path is Case Sensitive. I split the domain part and path and store them separately in the Database's columns.
Each row in the table has an auto-generated numeric ID. This ID is represented in HEX format in the hexid column, exactly this hex value is the part of the new Short URL.

When the user enters an incorrect URL, he gets error information.

Requirements:

• Java 11 - to compile and run the app you have to have Java version 11.

    How to use specific JDK version you can find here: 
    https://stackoverflow.com/questions/18487406/how-do-i-tell-gradle-to-use-specific-jdk-version
  

Minimal Configuration

• All parameters are in the ./src/main/resources/application.yml file and have default values - this is enough to start the App (except db path)
• you can redefine most of the configuration properties using the command line.

Run application

• Go to the application directory

• Type in the terminal/command line:

    gradlew bootRun --args='--DS_URL=jdbc:h2:file:/opt/h2-shortener'
  
    where value is:
        - /opt/h2-shortener ~ is an absolute path to the 
            H2 Database file (file name is `h2-shortener`). 
            It will be created automatically during the first starting. 
            The directory must be writeable for the current user. 
  

• Open in your favorite browser http://localhost:8181