Struct coap_message_utils::Error

pub struct Error { /* private fields */ }

A build-time-flexible renderable error type

This is used wherever this crate produces errors, and also recommended for outside handlers – the idea being that the more code parts share a type, the more compact code can be emitted.

Depending on what gets configured, it may just be a single u8 error code, or it may contain more details such as the number of the option that could not be processed, or any other Standard Problem Details (RFC9290).

Implementations

impl Error

pub fn bad_option(unprocessed_option: u16) -> Self

Create an error response for an unprocessed option

The response is rendered with a single unprocessed-coap-option problem detail if that feature is enabled.

If the unprocessed option has a special error code (e.g. Accept => 4.06 Not Acceptable or Content Format => 4.15 Unsupported Content-Format), that code is emitted instead of the default 4.02 Bad Option, and the unprocessed-coap-option problem details is not emitted.

Note that the CoAP option number is given as a u16, as is common around the CoAP crates (even though 0 is a reseved value). It is an error to pass in the value 0; the implementation may treat this as a reason for a panic, or silently ignore the error and not render the problem detail.

pub fn bad_request_with_rbep(byte: usize) -> Self

Create a 4.00 Bad Request error with a Request Body Error Position indicating at which position in the request’s body the error occurred

If the crate is compiled without the error_request_body_error_position feature, the position information will be ignored. The value may also be ignored if it exceeds an internal limit of how large values can be expressed.

pub fn bad_request() -> Self

Create an otherwise empty 4.00 Bad Request error

pub fn not_found() -> Self

Create an otherwise empty 4.04 Not Found error

pub fn method_not_allowed() -> Self

Create an otherwise empty 4.05 Method Not Allowed error

pub fn internal_server_error() -> Self

Create an otherwise empty 5.00 Internal Server Error error

pub fn service_unavailable() -> Self

Create an otherwise empty 5.03 Service Unavailable error

pub fn with_max_age(self, max_age: u32) -> Self

Available on crate feature error_max_age only.

Set a Max-Age

Unlike the constructors that set error details, this modifier is only available when the data is actually stored, because not emitting it is not just elision of possibly helful details, but may change the networks’ behavior (for example, because a long Max-Age is not sent and the client keeps retrying every minute).

Trait Implementations

impl Debug for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl RenderableOnMinimal for Error

type Error<IE: RenderableOnMinimal + Debug> = IE

Error to return when even the error rendering is unsuccessful (a “double error”).

fn render<M: MinimalWritableMessage>( self, message: &mut M ) -> Result<(), Self::Error<M::UnionError>>

Express the error in a CoAP response message