🔑 HashMapLive

A lightweight Spring Boot-based live key-value map API. Designed for local development or self-hosted environments such as home automation hubs, configuration sync tools, IoT devices, and more.

Built by Riley Simmons

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💡 Features

• Simple REST API for setting and retrieving key-value pairs
• In-memory H2 database by default (optional to swap for PostgreSQL, MySQL, etc.)
• Fully self-hosted with no external dependencies
• Can be used with curl, PowerShell, Postman, Python, or any HTTP client
• Useful for:
  • 💡 Smart home control state
  • 🧪 Live config servers
  • 🔁 Local dev/test service communication

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🚀 Getting Started

1. Clone the Repository

git clone https://github.com/Onlyriley/HashMapLive.git
cd HashMapLive

2. Run with Maven

./mvnw spring-boot:run

Make sure you have Java 17+ installed (or update the project to match your version).

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🔌 API Endpoints

➕ POST /api/map

Create or update a key-value pair.

Example

POST http://localhost:8080/api/map?key=lightsOn&value=true

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🔍 GET /api/map

Retrieve the value associated with a key.

Example

GET http://localhost:8080/api/map?key=lightsOn

Response

true

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🧪 Testing Locally (PowerShell / Curl)

Invoke-RestMethod -Method POST "http://localhost:8080/api/map?key=myDevice&value=online"
Invoke-RestMethod "http://localhost:8080/api/map?key=myDevice"

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🔧 Configuration (optional)

You can switch the database engine by modifying application.properties:

# Use PostgreSQL instead of H2
spring.datasource.url=jdbc:postgresql://localhost:5432/hashmaplive
spring.datasource.username=postgres
spring.datasource.password=yourpass
spring.jpa.hibernate.ddl-auto=update

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🖥️ H2 Console (debugging)

Access the in-memory DB in your browser:

http://localhost:8080/h2-console

• JDBC URL: jdbc:h2:mem:testdb
• Username: sa
• Password: (leave blank)

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📁 Project Structure

src/
├── controller/      → REST API layer
├── model/           → JPA entity for key-value storage
├── repository/      → Spring Data repository
└── HashMapLiveApplication.java

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📜 License

MIT License

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🤝 Contributing

Pull requests are welcome! Ideas for additional features:

• TTL/expiring keys
• Redis backend support
• WebSocket broadcasting on update
• Admin UI dashboard

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✨ Acknowledgements

• Built using Spring Boot + H2
• Inspired by minimal self-hosted tools like Etcd, Consul, and Home Assistant integrations