Module message 

RpcRequest trait for type-safe RPC calls

This module defines the RpcRequest trait which associates RPC Request types with their corresponding Response types. This enables compile-time type safety for client-side RPC calls through type inference.

Design Rationale

Without the RpcRequest trait, client code must manually:

1. Encode the request into bytes
2. Specify the route_key as a string (prone to typos)
3. Manually decode the response (can use wrong type)

With the RpcRequest trait, the framework can provide type-safe APIs:

// Type-safe: compiler infers EchoResponse from EchoRequest::Response
let response: EchoResponse = ctx.call(target, request).await?;

Implementation

The RpcRequest trait is implemented by the code generator for each protobuf message that represents an RPC request:

impl RpcRequest for EchoRequest {
    type Response = EchoResponse;
}

Placement in actr-protocol

This trait is placed in actr-protocol (not actr-framework) because:

• It’s a pure type-level association with no async methods
• It only depends on prost::Message and standard traits
• It can be independently tested without runtime dependencies
• It follows the “data definition layer” principle of actr-protocol

Traits

RpcRequest

Associates an RPC Request type with its Response type for type-safe RPC calls.