Trait Code

pub trait Code: Into<u8> + TryFrom<u8> {
    type Error: Debug + RenderableOnMinimal;

    // Required method
    fn new(code: u8) -> Result<Self, <Self as Code>::Error>;
}

A message code A CoAP code

For the code’s meaning, see the CoAP Codes IANA subregistry or the coap_numbers::code module that lists them.

All code implementations can be converted to u8 (as they correspond to an 8-bit unsigned integer in the CoAP protocol). The conversion back is fallible to allow strict message implementations to only accept codes supported by the implementation, and/or to limit the values by type state. For example, a strict implementation may distinguish between request and response messages, and only allow the respective code class into their objects (simultaneously creating usable niches in the in-memory representations).

Required Associated Types

type Error: Debug + RenderableOnMinimal

Error of the .new() method; ideally, this is also the TryFrom::Error (which can not be restricted without Associated type bounds being stabilized).

Once that is available, the built-in new method will be deprecated and eventually removed – a change that will be trivial on code using it provided that this error is indeed the error of TryFrom.

The error, when rendered, should represent a 5.00 style error, because what went wrong was that the server CoAP library can not represent the response code intended by the handler.

Required Methods

fn new(code: u8) -> Result<Self, <Self as Code>::Error>

This constructor is a more concrete variant of the TryFrom function whose error code is practically usable (see Self::Error)

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl Code for u8

type Error = Infallible

fn new(code: u8) -> Result<Self, Infallible>

Implementors