Enum MqttError 

#[non_exhaustive]
pub enum MqttError {
    Connect(Box<dyn StdError + Send + Sync>),
    Subscribe {
        filter: String,
        reason: String,
    },
    Receive(String),
    Publish {
        topic: String,
        reason: String,
    },
    NotConnected,
    Invalid(String),
}

Errors returned by the MQTT 5 broker.

One enum for the whole crate, variants by source, per the RustStream broker conventions. The wrapped sources are boxed std errors so the public API does not leak the client’s error types.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Connect(Box<dyn StdError + Send + Sync>)

Establishing the connection failed (transport, TLS, or the broker refused the connection with a non-retryable reason).

Subscribe

Subscribing failed (the broker rejected the filter, or the connection died).

Fields

filter: String

The topic filter the subscription targeted.

reason: String

The rejection or transport reason.

Receive(String)

The connection failed permanently while receiving.

Publish

Publishing failed: the connection task is gone, the topic is not one a publish can name (empty, or carrying a wildcard), or the topic or a header is not text an MQTT string carries (not UTF-8, or holding a control character or a Unicode non-character).

Fields

topic: String

The topic the message targeted.

reason: String

The failure reason.

NotConnected

The handle is used before connect filled the shared connection, or after shutdown.

Invalid(String)

A broker option or subscription descriptor is invalid.

Trait Implementations

impl Debug for MqttError

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

Formats the value using the given formatter.

impl Display for MqttError

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

Formats the value using the given formatter.

impl Error for MqttError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.