Food Vending Machine (in progress)

A terminal-based vending machine server in C++20. Each TCP connection is an independent session where clients browse products, build an order, and go through a payment flow. Built to explore ASIO and MySQL integration.

Stack: C++20 · Standalone ASIO · MySQL Connector/C++ · GNU Make · Docker

Project Structure

food_vending_machine/
  src/         Source files
  include/     Header files
sql/           Database initialization scripts
docker-compose.yaml

Setup

Start MySQL with Docker:

docker compose up -d

This runs the scripts in sql/ automatically.

Credentials are hardcoded in food_vending_machine/src/client_session.cpp.

Build:

cd food_vending_machine && make

Running

./food_vending   # from food_vending_machine/

Listens on port 6666. Connect with telnet localhost 6666.

Commands

Command	Description
LIST	Show available products with IDs and prices.
SELECT <id/name...>	Add products to the order by ID or name.
CONFIRM	Confirm the order and start the payment flow.
QUIT	End the session.

Payment flow: after CONFIRM, select a payment method by number (or 0 to cancel). Then enter the payment amount when prompted. Payment is processed asynchronously, the result is pushed back to the client.

Architecture

Component	Responsibility
ClientSession	Manages TCP connection and async I/O.
FoodVmController	Parses commands and drives application logic.
FoodVmOrder	Holds the current order and tracks its state.
FoodVmPayment	Simulates async payment processing via ASIO timers.
FoodVmDatabase	Encapsulates all MySQL operations.
FoodVmNotification	Generic callback wrapper for async event delivery.