An introduction to the OpenAI API using Python

Introduction

Ever wanted to play chess against an AI? With the OpenAI API, you can! This blog post will show you how to use Python to interface with the OpenAI API, send and receive requests, and even play a game of chess against an AI opponent. We’ll be using the FEN representation of the chess board to communicate game states with the API.

Setting Up

Before we start, make sure you have the following:

• Python installed on your machine (preferably Python 3.6 or later)
• A valid OpenAI API key (you can sign up at https://beta.openai.com/signup/)

To install the OpenAI package, run the following command:

pip install openai

Now, let’s import the required libraries and set up the API key:

import openai
import os

openai.api_key = os.environ["OPENAI_API_KEY"]

Make sure to replace “OPENAI_API_KEY” with your actual API key or set it as an environment variable.

Interacting with the OpenAI API

Now that we have the API key set up, let’s create a function to send a prompt to the OpenAI API and receive a response. The function will receive the current FEN representation of the chess board and return the next FEN representation after the AI’s move.

def get_next_move(fen):
    prompt = f"Given the chess position in FEN notation: {fen}, what is the best move? Please provide the resulting FEN representation after the move."
    
    response = openai.Completion.create(
        engine="text-davinci-002",
        prompt=prompt,
        max_tokens=100,
        n=1,
        stop=None,
        temperature=0.5,
    )
    
    return response.choices[0].text.strip()

This function sends a POST request to the OpenAI API with the current FEN representation and receives the next FEN representation after the AI’s move.

Playing Chess

Now let’s create a simple chess game loop that takes user input and sends it to the API for processing. We’ll be using the python-chess library to handle the FEN representation and validate moves. You can install it with:

pip install python-chess

Here’s the code to set up a simple chess game:

import chess

board = chess.Board()

while not board.is_game_over():
    print(board)
    if board.turn == chess.WHITE:
        move = input("Your move (in UCI format): ")
        try:
            board.push_san(move)
        except ValueError:
            print("Invalid move, try again.")
            continue
    else:
        print("AI is thinking...")
        current_fen = board.fen()
        next_fen = get_next_move(current_fen)
        try:
            board.set_fen(next_fen)
        except ValueError:
            print("Error: AI provided an invalid FEN.")
            break

This code sets up a chess board and enters a game loop where the user (White) enters moves in UCI format, and the AI (Black) calculates its move using the OpenAI API.

Conclusion

And there you have it! You’ve created a simple chess game using the OpenAI API and Python.