Module macros 

Macros for HTTP handlers.

These macros simplify the common pattern of sending an RPC request and converting the response to an HTTP response.

Type flow

oneshot_request(req)  -> Option<T>
rpc_request!(...)     -> AppResult<T>      (= Result<T, AppError>)
jsonify_rpc!(...)     -> AppResult<Json<T>> (= Result<Json<T>, AppError>)

The Option<T> from oneshot_request represents channel status:

• Some(T) - response received
• None - channel dropped (converted to AppError::ChannelDropped)

Note: T is often itself an Option<U>, where None means “no data available” (serialized as null). This is distinct from channel failure.