Imlight

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Message Handling ​

Overview ​

Imlight's message handling system supports custom protocols and dispatchers that route messages between the actors that exist in the system. The system uses strongly-typed messages to ensure type safety and clarity in communication.

Message Types ​

There are two distinct types of messages that a session actor can process:

  • Client Messages (IMessage)
  • Server Messages (IServerMessage)

Messages are categorized into message protocols. A protocol is a group of related messages that share a common purpose or functionality. Each protocol is identified by a unique service ID.

Client protocols have service IDs ranging from 1 to 99, while server protocols have service IDs greater than 100. Protocols are a class, and their service ID is embedded into their name. For example:

csharp
ACCOUNT_104_PROTOCOL
ACCOUNT_104_PROTOCOL

With this example, we can determine that this protocol has a service ID of 104, making it a server protocol.

Client Messages ​

Client messages are generated from the client's XML definitions via Imcodec. Each message corresponds to a specific action or request that the game client can make.

Server Messages ​

Server messages are defined by Imlight and follow the exact same structure as client messages. Their service ID will always be > 100.

Server messages differ in that they are never sent over the network, and are used for internal communication only. They are typically used for one Message Service to communicate with another, or session actor -> server actor communication.

Server messages are defined in the Imlight.CoreLib.Shared.Packets namespace.

Receive Protocol Dispatcher ​

The ReceiveProtocolDispatcher class is an abstraction for the actor model that allows for message handlers in a class to instead be identified using C# attributes.

For example:

csharp
[MessageHandler(typeof(LOGIN_7_PROTOCOL.MSG_DELETECHARACTER))]
private void ReceiveDeleteCharacter(LOGIN_7_PROTOCOL.MSG_DELETECHARACTER message) {
    // Do work here
}
[MessageHandler(typeof(LOGIN_7_PROTOCOL.MSG_DELETECHARACTER))]
private void ReceiveDeleteCharacter(LOGIN_7_PROTOCOL.MSG_DELETECHARACTER message) {
    // Do work here
}