README.md

battleship-api

This is a sample project I was asked to create while applying to a new job in April 2020. The task was to create a REST api to play battleship against the computer. This shows how I solved that task in 2020. I have learned a lot since then. The code therefore no longer corresponds completely to how I would do it today.

Documentation

Setup

If you have docker installed, just run

docker-compose up

On first run, you will need to run the queries from database.sql to initialize the database.

Gameplay

Start a new game

To start a new game, send an empty request to:

POST /new-game

You will then receive a token. You need to keep this token in order to access and play your game. There is no further authentication required.

After you started the game, the computer player will automatically place all his ships on his battleground and you will need to do this, too.

Place s ship on your own battleground

To place one of your own ships on your battleground, send a request to:

POST /game/{token}/ship

In the body you need to define which ship you want to place. Available ships are listed in the ShipFactory class. You only have one of each. You define the position of the ship by giving the coordinate for its upper left corner and the direction in which it should point to.

{
    "ship": "submarine",
    "field": "D2",
    "direction": "horizontal"
}

In this example, your submarine ship (length 3) would be placed horizontally on the fields D2, D3 and D4.

Fire a shot at your opponent's battleground

After you have placed all of your available ships, it is randomly selected if you or the computer player starts. If the computer starts, he will automatically place his shot. When it's your turn, you can place your shot on the opponent's battleground by making a request to:

POST /game/{token}/shot

In the body, just define the field you want to shoot at:

{
    "field": "A3"
}

Win the game

When the game has winner, you will see this in the response to your last shot. Additionally you won't be able to do any actions on the finished game. When trying to do that, you will get an appropriate message.

Computer player

The ComputerPlayer can do two things:

He can place all of his available ships on the battleground. You can control how he does that by using different implementations of the ShipPlacementStrategy.

He can also shoot his opponent's ships once (or more, as long as the last shot was a hit). The used implementation of ShootingStrategy determines how he calculates the next target position.

TODO

• Add more intelligent computer player strategies
• API response formatting wrapper
• API response for exceptions
• Improve performance
• Validation of inputs
• Switch from handling received shots to handle fired shots, should be more logically then.