Introduction

Once, the project was my test task for a job but while implementing the task I realized it would be a good demo for my portfolio, so I enhanced the project and made it public. The main idea of the project is that a user can add images into the system or create the whole slideshow. Each image has its duration to be displayed in a slideshow. It is supposed, that an image is stored somewhere(like AWS S3) beforehand and publicly available so we store only its URL and validate the image availability before storing it into a database. In this demo image samples are stored into MinIO, have a look at compose-infra.yml. You can run the project and add additional images via MinIO console to play around.
Additional requirements:

1. Track current image in a slideshow
2. Track proof-of-play events(when image was 'swiped')
3. Ensure not empty slideshows in the system

Key Features

• Image and slideshow CRUD operations
• Storing images by batches
• API documentation
• Graceful exception handling
• Parallel image validation

Technical Implementation

• Postgres as the primary database
• Flyway migrations
• Spring Boot 3.4
• Java 21
• Docker and Docker Compose
• Swagger API documentation
• Hibernate batch processing
• SQL window functions
• Pessimistic locks
• CompletableFuture usage for image validation parallelization
• MinIO as storage of image samples

Getting Started

Prerequisites

• Unix-like operating system(for Windows just manually execute commands from shell scripts and use mvnw.cmd instead)
• Docker and Docker Compose

Installation

1. Build the Project

./build.sh

2. Start the Application

docker compose up -d

The application is available at: http://localhost:8080

Database credentials:

URL: jdbc:postgresql://localhost:5432/slideshow
Username: admin
Password: password

MinIO console: http://localhost:9001

Username: admin
Password: password

Pre-downloaded images:
http://localhost:9000/images/beach.jpg
http://localhost:9000/images/birds.jpg
http://localhost:9000/images/butterfly.jpg
http://localhost:9000/images/mountain-lake.jpg
http://localhost:9000/images/tree.jpg

API documentation: http://localhost:8080/swagger-ui/index.html

NOTE: Since we run the application in Docker, for images stored in MinIO URL must use internal Docker Network DNS, i.e. minio as a host. For example: http://minio:9000/images/tree.jpg

3. Stop the Application

docker compose down

4. Clean Up

./clean.sh  # Removes local docker image

Future Improvements

1. Add users and make images and slideshows linked to a user
2. Add Spring Security and some authentication/authorization