🚨 Emergency Service Messaging System

A cross-platform emergency event messaging system implemented as part of the SPL - Systems Programming course at Ben-Gurion University.
The system enables users to connect, subscribe to topics, send and receive messages, and manage state in real-time using the STOMP protocol.

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🔧 Technologies Used

• Java (Server side)
• C++ (Client side, socket programming)
• STOMP Protocol over TCP
• JSON-based message structure
• Multithreading, Reactor Pattern
• Linux Sockets
• Git for version control
• Docker-compatible

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💡 Project Structure

client/

• src/, include/, bin/, data/ – C++ code and headers, build artifacts, and input/output files
• makefile – Used to compile the client

server/

• src/main/java/bgu/spl/net/ – Java server code implementing STOMP server
• pom.xml – Maven build file for server

Root directory

• events1.json – Sample input file
• events1_out.txt – Output summary file
• .devcontainer/ – Development environment configuration

.
├── client/
│   ├── bin/
│   ├── data/
│   ├── include/
│   ├── src/
│   └── makefile
├── server/
│   └── src/main/java/bgu/spl/net/
│   └── pom.xml
├── events1.json
├── events1_out.txt
├── README.md

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✨ Features

• Full support for the STOMP 1.2 protocol
• Real-time event broadcasting to subscribers
• Login & session tracking
• Multithreaded client handling (mutex-safe)
• Graceful disconnection & logout
• Custom event summary generation

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🚀 How to Run

Server

Navigate to the server/ directory and run:

mvn clean compile
mvn exec:java -Dexec.mainClass="bgu.spl.net.impl.stomp.StompServer" -Dexec.args="7777 tpc"
# or for reactor:
mvn exec:java -Dexec.mainClass="bgu.spl.net.impl.stomp.StompServer" -Dexec.args="7777 reactor"

Client

From the client/ directory:

make
cd bin
./StompEMIClient

Example Run

Each client should be started in a separate terminal.

Terminal 1 - Alice

login 127.0.0.1:7777 Alice 123
join police

Terminal 2 - Bob

login 127.0.0.1:7777 Bob abc
join police
report ../events1.json

Terminal 1 - Alice

summary police Bob ../events1_out.txt
logout

Terminal 2 - Bob

logout

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🖥️ Client Command Reference

Command	Description
login <host>:<port> <user> <pass>	Connects to the server and authenticates the client.
join <topic>	Subscribes to a topic (e.g., police, fire, etc.).
exit <topic>	Unsubscribes from a topic.
report <path>	Sends events to the server from a JSON file.
summary <topic> <user> <path>	Requests a summary of all events reported by a user on a topic. Output saved to path.
logout	Gracefully disconnects the client from the server.

📝 Example

report ../events1.json
summary police Bob ../events1_out.txt

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📊 Event File Format

Event report files should be in JSON format with the following structure:

{
  "channel_name": "<topic_name>",
  "events": [
    {
      "event_name": "<string>",
      "city": "<string>",
      "date_time": <unix_timestamp>,
      "description": "<string>",
      "general_information": {
        "active": <boolean>,
        "forces_arrival_at_scene": <boolean>
      }
    },
    ...
  ]
}

• channel_name defines the topic to which the events will be published.
• Each event includes metadata such as name, location, and time.
• The date_time field should be a UNIX timestamp (in seconds).
• general_information.active indicates whether the event is ongoing.
• general_information.forces_arrival_at_scene indicates whether emergency forces arrived at the scene.

You may include multiple events in the events array, as shown above.

Example files can be found under the project root, such as events1.json. Multiple such events can be sent as a JSON array.

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🧪 Testing & Debugging

• All features were manually tested with simulated users.
• Memory safety ensured via valgrind and code reviews.
• Server supports debugging printouts under verbose mode.

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🎓 Course Information

• Course: SPL - Systems Programming
• Institution: Ben-Gurion University of the Negev
• Year: 2025
• Environment: Linux CS Lab, Docker-compatible

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🧑‍💻 Authors

Ben Kapon
Student at BGU
LinkedIn

Itay Shaul
Student at BGU
LinkedIn

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📝 Important Note

This project was designed and tested on a Docker-compatible environment.
Ensure file paths and JSON formats are valid when running locally or in CI environments.

This project demonstrates a real-time messaging architecture using both low-level socket programming in C++ and scalable Java server design.