SocketDrop

SocketDrop is a lightweight real-time file sharing app built with Java and Spring Boot.
Users connect via WebSockets, join rooms, and share files with live progress updates — without authentication or a database.

Features

• WebSocket-based real-time communication
• Room-based file sharing
• File upload, download, and delete via HTTP
• Live transfer progress updates
• QR-code based room join (URL)
• In-memory storage only

HTTP API

• POST /file/uploads (multipart file, optional roomId for progress broadcast)
• GET /file/downloads/{fileId}
• DELETE /file/downloads/{fileId}

WebSocket API (/room)

• Client messages:
  • { "type": "CREATE_ROOM", "displayName": "alice" }
  • { "type": "JOIN_ROOM", "roomId": "room_x", "displayName": "bob" }
  • { "type": "LEAVE_ROOM" }
• Server messages:
  • ROOM_CREATED
  • ROOM_JOINED
  • UPLOAD_PROGRESS (STARTED, COMPLETED, FAILED)
  • ERROR

Frontend

• Static single-page UI is available at / via src/main/resources/static/index.html.
• Assets:
  • src/main/resources/static/app.js
  • src/main/resources/static/styles.css
• Supports create/join/leave room, room-scoped upload, room-authorized download, and delete.

Tech Stack

• Java 17
• Spring Boot
• Spring WebSocket
• Spring Web (REST)
• Maven

Notes

• No authentication
• No database
• Designed for learning and demonstration purposes

Containerized Run

Build and run with Docker

docker build -t socket-drop:latest .
docker run --rm -p 8080:8080 -v socket_drop_storage:/app/storage socket-drop:latest

Run with Docker Compose

docker compose up --build

Container environment variables

• SPRING_FILE_BASE_PATH (default: /app/storage)
• SPRING_FILE_MAX_SIZE (default in app: 524288000)
• SPRING_FILE_MAX_DOWNLOAD_SIZE (default in app: 52428800)
• SPRING_SERVLET_MULTIPART_MAX_FILE_SIZE (default: 50MB)
• SPRING_SERVLET_MULTIPART_MAX_REQUEST_SIZE (default: 50MB)

Author

Prince Pal

Created by Prince Pal with love.

LinkedIn: https://www.linkedin.com/in/princepal-dev/