Connecting an AI Agent to a Flash Game

Question

Overview

The game is a multiplayer simple real time strategy housed in a Flash application. Players run the Flash client, and are connected to a server written in another language (the language is irrelevant). Players compete against one another in games of 2~8 players.

My aim is create some way for people to create an AI agent to play in the same realm against human players, or other AI agents. Akin to the Broodwar AI competitions, but in a much simpler game.

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The current model

has players logging in to the lobby. Games seeking players are listed in the lobby. Once the game acquires the amount of players required to start (defined by the host at game room creation time), the players are then pushed into a game, and leave the lobby. Games then run through to completion; players who disconnect are left stagnant until destroyed or they login again and are reconnected to the game.

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In a perfect world

the flash client (Using an MVC type model) would be able to interface in some way with the users AI agent, handing data to the agent, and receiving commands from the agent. In this way the user could observe the game in the flash client while in play, as well as choose games for the agent to participate in. This model would be ideal for debugging purposes, as to not interrupt play on crash, and since commands can only be sent (with malformed commands being ignored, with an error callback) users could pick out major bugs quickly.

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However

flash is a prissy little nitwit when it comes to communicating client side to client side. The only realistic options I can see would be to create a second client interface in another language (say .Net) that would be used to interface the AI agent, the player would then login to the flash client and enter games/observe in the above mentioned manner. OR the flash client would create a second socket pointed at the local host. A suitable API would be created to manage the communication protocol (as a DLL or similair) that would handle all data values of the game, and sending commands. This API would be extended by the users AI agent, and the player would login to the flash client and join/observe games.

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The Big Question:

From experience or observations, what would be the most suitable model for this type of a system? I have no qualms with either, but due to the long timeframe of implementing each system (I work alone) I'd rather start off on the right path, and end up with an easy to use model. Any suggestions at all are very welcome!

Answer 1

So your goal is to provide an interface for developers to plug their AI on your game system. Depending on how much freedom you want to provide to those developers, you have several options.

1. For the largest freedom, do not provide anything but a comprehensive documentation of your network protocol as well as a set of IP to connect to (and maybe a test server).

   Using that approach, third-party developers are free to develop an AI in any language they are the most comfortable with, as soon as it supports sockets. On the downside, your server have to be quite secure and stable to avoid cheating and attacks. But that should be the case anyway.

2. For almost as much freedom, provides a library that allows to connect and interact with your game server. If you want to stick to Flash, you can give the developers an SWC. This way, they could create their own Flash app, that connects and interact with your game server using your library.

   This is maybe more flexible, since you can update the library when changing your network protocol, without breaking the third-party applications (or at least, with giving them a quite easy way to update, compared to a random change in the protocol).

3. You could also set up your game client so it will be able to read client-side scripts. For example, you could use LUA. This way, you are really sandboxing the third-party code on your very own game client, and you keep all control over the API you'll be providing.

If you'd like to specify your request more deeply, I'd be happy to update the answer with more details.

Answer 2

You could probably use flash.net.LocalConnection for this. This would allow you to implement an API where other flash files can connect to and run commands locally.

What this means is, that you'll have your game client (running in the browser) which exposes methods through LocalConnection. Somebody that implements an A.I. for your client could either run an Adobe AIR application, or another SWF file in the browser that connects to your LocalConnection and issues commands over it.

This could get cumbersome with lots of exposed methods and requires really good documentation, so that somebody can work with your API.

Another option would be to expose a RESTful web API, that any client can connect to. So the A.I. could be implemented in any language that can issue an HTTP-request.