Enum Error 

pub enum Error {
    Failure,
    PersistenceError,
    Disconnected,
    MaxMessagesInflight,
    BadUtf8String,
    NullParameter,
    TopicNameTruncated,
    BadStructure,
    BadQos,
    NoMoreMsgIds,
    OperationIncomplete,
    MaxBufferedMessages,
    SslNotSupported,
    BadProtocol,
    BadMqttOption,
    WrongMqttVersion,
    ZeroLenWillTopic,
    CommandIgnored,
    MaxBufferedZero,
    TcpConnectTimeout,
    TcpConnectCompletionFailure,
    TcpTlsConnectFailure,
    SocketError(i32),
    ConnectReturn(ConnectReturnCode),
    ReceivedDisconnect(i32),
    Publish(i32, Message),
    ReasonCode(ReasonCode, Properties),
    BadTopicFilter,
    Io(Error),
    Utf8(Utf8Error),
    Nul(NulError),
    MissingSslOptions,
    Conversion,
    Timeout,
    General(&'static str),
    GeneralString(String),
}

The errors from an MQTT operation.

Variants

Failure

A generic error code indicating the failure of an MQTT client operation.

PersistenceError

Persistence error

Disconnected

The client is disconnected.

MaxMessagesInflight

The maximum number of messages allowed to be simultaneously in-flight has been reached.

BadUtf8String

An invalid UTF-8 string has been detected.

NullParameter

A NULL parameter has been supplied to the underlying C library when this is invalid.

TopicNameTruncated

The topic has been truncated (the topic string includes embedded NULL characters). String functions will not access the full topic. Use the topic length value to access the full topic.

BadStructure

A structure parameter passed down to the C library does not have the correct eyecatcher and version number.

BadQos

An invaid QoS value was used not 0, 1, or 2)

NoMoreMsgIds

All 64k MQTT message ID are currently in use

OperationIncomplete

The request is being discarded when not complete

MaxBufferedMessages

The limit on the maximum number of message buffers has been reached.

SslNotSupported

Attempting SSL connection using non-SSL version of library.

BadProtocol

A bad URL protocol/schema was requested/ Note that the TLS enabled prefixes (ssl, mqtts, wss) are only valid if the TLS version of the library is linked int the app.

BadMqttOption

Don’t use options for another version of MQTT

WrongMqttVersion

Call not applicable to the client’s version of MQTT

ZeroLenWillTopic

The LWT topic can not be zero length

CommandIgnored

Connect or disconnect command ignored because there is already a connect or disconnect command at the head of the list waiting to be processed. Use the onSuccess/onFailure callbacks to wait for the previous connect or disconnect command to be complete.

MaxBufferedZero

The max number of buffered messages can not be zero. The library needs at least one slot for the outbound message.

TcpConnectTimeout

The TCP connection timed out

TcpConnectCompletionFailure

The TCP connection failed to complete

TcpTlsConnectFailure

TCP/TLS connection failure

SocketError(i32)

A socket error occurred

ConnectReturn(ConnectReturnCode)

ReceivedDisconnect(i32)

Publish(i32, Message)

A synchronous error when publishing creating or queuing the message.

ReasonCode(ReasonCode, Properties)

An MQTT v5 error from a reason code. Any reason code >= 0x80 indicates an error.

BadTopicFilter

A bad topic filter

Io(Error)

An low-level I/O error

Utf8(Utf8Error)

An error parsing a UTF-8 string

Nul(NulError)

A string NUL error

MissingSslOptions

Missing SSL/TLS options

Conversion

Conversion error between types

Timeout

A timeout, particularly from a synchronous operation.

General(&'static str)

A general error with description

GeneralString(String)

A general error with description

Implementations

impl Error

pub fn from_return_code(rc: i32) -> Error

Create an error from a Paho C return code.

These should not be confused with Connect Return Codes (v3.x) or Reason Codes (v5), although the C lib is sometimes vague about which integer value it is returning.

pub fn from_connect_return_code(code: u8) -> Error

Create an error from an MQTT v3 Connect Return Code

pub fn from_reason_code(code: u8, props: Properties) -> Error

Create an error from an MQTT v5 Reason Code and properties

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

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.

impl From<&'static str> for Error

fn from(descr: &'static str) -> Error

Create a general error from a string.

impl From<(i32, &str)> for Error

fn from(_: (i32, &str)) -> Error

Convert a Paho C return code w/ reason string to an Error.

The Paho C library passes up error description strings that are supposed to be for “additional” information, but they actually describe specific errors that should have been enumerated. This is somewhat of a hack to use the string to enumerate errors. These strings are pulled directly from the C sources, and could change.

impl From<(i32, Option<String>)> for Error

fn from(_: (i32, Option<String>)) -> Error

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Error

Converts to this type from the input type.

impl From<IntoStringError> for Error

fn from(_: IntoStringError) -> Error

Converts to this type from the input type.

impl From<NulError> for Error

fn from(source: NulError) -> Error

Converts to this type from the input type.

impl From<String> for Error

fn from(descr: String) -> Error

Create a general error from a string.

impl From<Utf8Error> for Error

fn from(source: Utf8Error) -> Error

Converts to this type from the input type.

impl From<i32> for Error

fn from(rc: i32) -> Error

Create an error from a Paho C return code.