Enum SmtpError 

pub enum SmtpError {
    Io(IoError),
    Protocol(ProtocolError),
    Auth(AuthError),
    InvalidInput(InvalidInputError),
    Policy(PolicyError),
}

Top-level error type for all SMTP operations.

Logging caveat

The Display output of SmtpError (and of the variants Protocol(ProtocolError) and Auth(AuthError) in particular) embeds the server’s reply text verbatim. SMTP servers commonly include the rejected envelope address in their reply — e.g. 550 5.1.1 <user@example.com>: recipient does not exist — and may include other PII the application would not log of its own accord. When emitting these errors to a shared log channel, consider:

• Logging only the structured fields you care about (during, actual, enhanced, code) and not the free-text message field.
• Truncating the message to a fixed length.
• Filtering / redacting addresses with an application-level regex if your compliance posture requires it.

joined_text() (the source of the message fields) is documented to potentially contain \n; see crate::protocol::Reply::joined_text.

Variants

Io(IoError)

Underlying transport (socket) failure, including connection close.

Protocol(ProtocolError)

Server response did not match SMTP grammar or expected code.

Auth(AuthError)

Authentication exchange failed or no compatible mechanism was offered.

InvalidInput(InvalidInputError)

Caller-supplied input violated SMTP constraints before any byte was sent on the wire.

Policy(PolicyError)

A crate::policy::SendPolicy rejected the send before any SMTP command was issued.

Trait Implementations

impl Debug for SmtpError

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

Formats the value using the given formatter.

impl Display for SmtpError

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

Formats the value using the given formatter.

impl Error for SmtpError

fn source(&self) -> Option<&(dyn StdError + '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<AuthError> for SmtpError

fn from(value: AuthError) -> Self

Converts to this type from the input type.

impl From<InvalidInputError> for SmtpError

fn from(value: InvalidInputError) -> Self

Converts to this type from the input type.

impl From<IoError> for SmtpError

fn from(value: IoError) -> Self

Converts to this type from the input type.

impl From<PolicyError> for SmtpError

fn from(value: PolicyError) -> Self

Converts to this type from the input type.

impl From<ProtocolError> for SmtpError

fn from(value: ProtocolError) -> Self

Converts to this type from the input type.