Asynchronous Request System

Overview

The following page describes the classes the client uses to make asynchronous JSON requests to the webserver.

AsyncJSONRequest

The AsyncJSONRequest is a wrapper class around Unity's WWW and WWWForm classes for making asynchronous POST and GET HTTP requests to the AsyncRPGWebServer. Unity's coroutine mechanism is used to make this request non-blocking. Because coroutines only work on Unity components, the static AsyncJSONRequest.Create() method is used to "hop-on" an instance of the AsyncJSONRequest component to a given game object. UI Model classes create these requests using the game object associated with the game state that owns the Model class (see Model-View-Controller in the UI System page).

All AsyncRPGServer web requests return a JSON string. The AsyncJSONRequest class attempts to parse this string into a JsonData instance (from the LitJSON library, basically a dictionary). The Model class that issued the request gets the JsonData blob using the GetRequest() method and pulls out the fields it cares about.

Compound Async Requests

Player movement requests are interesting because they are actually a two-stage asynchronous request. The first stage is to do an asynchronous path finding request to the PathFindingSystem, which takes place totally on the client. The second stage, pending a successful path find, sends the appropriate AsyncJSONRequest to the web server. In order to make the client code simpler, we wrap these compound async request classes into a single helper class. All of these request classes will return a list of game events that resulted from the player's movement upon successful completion of the request:

• AsyncCharacterMoveRequest - Move to the player to desired target in the room.
• AsyncCharacterPortalRequest - Move the player through desired target portal (door, stairs, or transporter) to an adjacent room.
• AsyncDrainEnergyTankRequest - Move the player to an energy tank in the current room and attempt to drain energy from it.
• AsyncHackEnergyTankRequest - Move the player to an energy tank in the current room and attempt to make it owned by the player faction (must be player faction to drain it).