HTML5 Canvas, 2nd Edition

The Basic Architecture of an ElectroServer Application

ElectroServer acts very much like the socket-server application we described in the previous section. It listens on specified ports for different protocols; when messages arrive, they are routed back to the connected clients.

However, ElectroServer has some specific features that we should discuss. Some of these exist on other socket-server platforms, while some don’t. However, much of this discussion will still be applicable to other socket servers when they make JavaScript APIs available.

Client

The client for an ElectroServer application is a program written in one of the API-supported language platforms, including Flash ActionScript 2, Flash ActionScript 3, Java, Objective-C, C#/.NET, and now JavaScript. The client is the application, which the user will manipulate to send messages through the API to ElectroServer. This is usually a game, a chat room, a virtual world, or some other kind of multiuser social or communication application.

All the communication with ElectroServer is event-based. The client application uses the JavaScript API to send events, and the client defines event handlers that listen for messages from ElectroServer. All of these messages and events are communicated through the API, which in turn is communicating through port 8989 using the BinaryHTTP protocol (at least for our examples).

Zones, rooms, and games

When a user first connects to ElectroServer, she needs to join or create a zone, which is simply a ...