Enum MailerError 

pub enum MailerError {
    InvalidMessage(String),
    Unauthorized(String),
    Rejected(String),
    Transport(String),
    RateLimited(String),
    Unknown(String),
}

Why a send failed, classified in a backend-neutral way.

The inner String carries backend-provided detail suitable for logs and error pages. Do not parse it; use the variant for branching.

Variants

InvalidMessage(String)

The message is malformed before the backend even tries to send: missing recipient, empty body, forbidden header, attachment too large. The caller MUST NOT retry blindly — the message needs to change.

Unauthorized(String)

The caller is not authorised to send as from.email (SES unverified sender, SMTP AUTH refused for that domain, etc). Usually a config problem.

Rejected(String)

The backend explicitly rejected the message after accepting the request: policy reasons, spam filter, recipient on suppression list. Do not retry.

Transport(String)

Transient delivery problem at the transport layer (TCP reset, DNS failure, 5xx SMTP reply, 5xx API response). Safe to retry with backoff.

RateLimited(String)

The backend asked the caller to slow down (SMTP 421, SES throttling exception). Retry after a delay.

Unknown(String)

Anything the backend couldn’t classify. Treat like Transport unless you have reason to believe otherwise.

Implementations

impl MailerError

pub fn invalid(message: impl Into<String>) -> Self

pub fn unauthorized(message: impl Into<String>) -> Self

pub fn rejected(message: impl Into<String>) -> Self

pub fn transport(message: impl Into<String>) -> Self

pub fn rate_limited(message: impl Into<String>) -> Self

pub fn unknown(message: impl Into<String>) -> Self

pub fn message(&self) -> &str

Borrow the inner detail string, regardless of variant.

Trait Implementations

impl Clone for MailerError

fn clone(&self) -> MailerError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MailerError

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for MailerError

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for MailerError

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

Formats the value using the given formatter.

impl Error for MailerError

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 PartialEq for MailerError

fn eq(&self, other: &MailerError) -> 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 Serialize for MailerError

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for MailerError

impl StructuralPartialEq for MailerError