Enum MqttError 

pub enum MqttError<'e> {
    Network(ErrorKind),
    Server,
    Alloc,
    AuthPacketReceived,
    Disconnect {
        reason: ReasonCode,
        reason_string: Option<MqttString<'e>>,
        server_reference: Option<MqttString<'e>>,
    },
    RecoveryRequired,
    PacketIdentifierNotInFlight,
    RepublishQoSNotMatching,
    PacketIdentifierAwaitingPubcomp,
    PacketMaximumLengthExceeded,
    ServerMaximumPacketSizeExceeded,
    InvalidTopicAlias,
    SessionBuffer,
    SendQuotaExceeded,
    IllegalDisconnectSessionExpiryInterval,
}

The main error returned by crate::client::Client.

Distincts between unrecoverable and recoverable errors. Recoverability in this context refers to whether the current network connection can be used for further communication after the error has occured.

Recovery

• For unrecoverable errors, crate::client::Client::abort can be called to send an optional DISCONNECT packet if allowed by specification. You can then try to recover the session by calling crate::client::Client::connect again without clean start.
• For recoverable errors, follow the error-specific behaviour.

Variants

Network(ErrorKind)

An underlying Read/Write method returned an error.

Unrecoverable error. crate::client::Client::abort should be called.

Server

The remote server did something the client does not understand / does not match the specification.

Unrecoverable error. crate::client::Client::abort should be called.

Alloc

A buffer provision by the crate::buffer::BufferProvider failed. Therefore a packet could not be received correctly.

Unrecoverable error. crate::client::Client::abort should be called.

AuthPacketReceived

An AUTH packet header has been received by the client. AUTH packets are not supported by the client. The client has scheduled a DISCONNECT packet with ReasonCode::ImplementationSpecificError. The packet body has not been decoded.

Unrecoverable error. crate::client::Client::abort should be called.

Disconnect

The client could not connect to the broker or the broker has sent a DISCONNECT packet.

Unrecoverable error. crate::client::Client::abort should be called.

Fields

reason: ReasonCode

The ReasonCode of the causing CONNACK or DISCONNECT packet. If the disconnection is caused by a CONNACK packet, the reason code ss always erroneous.

reason_string: Option<MqttString<'e>>

The reason string property of the causing CONNACK or DISCONNECT packet if the server included a reason string.

server_reference: Option<MqttString<'e>>

The server reference property of the causing CONNACK or DISCONNCET packet if the server included a server reference. Identifies another server which can be used.

RecoveryRequired

Another unrecoverable error has been returned earlier. The underlying connection is in a state, in which it refuses/is not able to perform regular communication.

Unrecoverable error. crate::client::Client::abort should be called.

PacketIdentifierNotInFlight

A republish of a packet without an in flight entry was attempted.

Recoverable error. No action has been taken by the client.

RepublishQoSNotMatching

A republish of a packet with a quality of service that does not match the quality of service of the original publication was attempted.

Recoverable error. No action has been taken by the client.

PacketIdentifierAwaitingPubcomp

A republish of a packet whose corresponding PUBREL packet has already been sent was attempted. Sending the PUBLISH packet in this case would result in a protocol violation.

Recoverable error. No action has been taken by the client.

PacketMaximumLengthExceeded

A packet was too long to encode its length with the variable byte integer.

This can currently only be returned from crate::client::Client::publish or crate::client::Client::republish.

Recoverable error. No action has been taken by the client.

ServerMaximumPacketSizeExceeded

A packet is too long and would exceed the servers maximum packet size.

Recoverable error. No action has been taken by the client.

InvalidTopicAlias

The value of a topic alias in an outgoing PUBLISH packet was 0 or greater than the server’s maximum allowed value. Sending this PUBLISH packet would raise a protocol error.

Recoverable error. No action has been taken by the client.

SessionBuffer

An action was rejected because an internal buffer used for tracking session state is full.

Recoverable error. Try again after a crate::client::event::Event has been emitted that indicates that buffer might be free again.

Example: crate::client::Client::subscribe returns this error. Wait until a crate::client::event::Event::Suback is received. This clears a spot in the subscribe packet identifiers.

SendQuotaExceeded

A publish now would exceed the server’s receive maximum and ultimately cause a protocol error.

Recoverable error. Try again after either crate::client::event::Event::PublishAcknowledged or crate::client::event::Event::PublishComplete has been emitted that indicates that buffer might be free again. been emitted that indicates that buffer might be free again.

IllegalDisconnectSessionExpiryInterval

A disconnect now with the given session expiry interval would cause a protocol error.

A disconnection was attempted with a session expiry interval change where the session expiry interval in the CONNECT packet was zero (crate::config::SessionExpiryInterval::EndOnDisconnect) and was greater than zero (crate::config::SessionExpiryInterval::NeverEnd or crate::config::SessionExpiryInterval::Seconds) in the DISCONNECT packet.

Recoverable error. Try disconnecting again without an session expiry interval or with a session expiry interval of zero (crate::config::SessionExpiryInterval::EndOnDisconnect).

Implementations

impl Error<'_>

pub fn is_recoverable(&self) -> bool

Returns whether the client can recover from this error without closing the network connection.

Trait Implementations

impl<'e> Clone for Error<'e>

fn clone(&self) -> Error<'e>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'e> Debug for Error<'e>

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

Formats the value using the given formatter.

impl From<Reserved> for Error<'_>

fn from(_: Reserved) -> Self

Converts to this type from the input type.

impl From<TooLargeToEncode> for Error<'_>

fn from(_: TooLargeToEncode) -> Self

Converts to this type from the input type.

impl<'e> PartialEq for Error<'e>

fn eq(&self, other: &Error<'e>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'e> Eq for Error<'e>

impl<'e> StructuralPartialEq for Error<'e>