Attribute Macro on_message 

#[on_message]

Marks a method as a protobuf message handler.

Use this to handle specific protobuf message types. The message type is inferred from the method’s parameter type, which should be a mapped protobuf message struct.

The method will automatically decode binary message data and call your handler with the decoded message object.

Parameters

A decoded handler can receive:

• ctx: &Context (optional)
• One protobuf message by value or shared reference

A raw handler can instead receive:

• ctx: &Context (optional)
• One supported message enum by value or shared reference
• payload: &[u8]

Parameters can appear in any order. Return ObserverResult.

Supported Message Types

• CDotaUserMsgChatMessage and other Dota 2 messages
• CCitadelUserMsgChatMsg and other Deadlock messages
• CCsUsrMsgVguiMenu and other CS2 messages
• Other mapped protobuf message types

Examples

Handle Dota 2 chat messages

#[on_message]
fn on_chat(&mut self, ctx: &Context, msg: CDotaUserMsgChatMessage) -> ObserverResult {
    println!("[{}] {}", ctx.tick(), msg.message_text());
    Ok(())
}

Handle without context

#[on_message]
fn on_chat(&mut self, msg: CDotaUserMsgChatMessage) -> ObserverResult {
    println!("Message: {}", msg.message_text());
    Ok(())
}

Handle by reference

#[on_message]
fn on_chat(&mut self, msg: &CDotaUserMsgChatMessage) -> ObserverResult {
    println!("Message: {}", msg.message_text());
    Ok(())
}

Handle raw messages

#[on_message]
fn on_raw(&mut self, msg_type: SvcMessages, payload: &[u8]) -> ObserverResult {
    println!("{msg_type:?}: {} bytes", payload.len());
    Ok(())
}