Enum Error 

pub enum Error {
    Io(Error),
    Config {
        file: String,
        line: usize,
        message: String,
    },
    Json {
        line: usize,
        column: usize,
        message: String,
    },
    Template {
        file: String,
        line: usize,
        column: usize,
        message: String,
    },
    Protocol(String),
    Unavailable(String),
    Message(String),
}

Every failure the framework itself can produce.

Application errors are expected to convert into this through From, which is what lets a handler return Result<T, E> and still be a valid handler.

Variants

Io(Error)

A file could not be read or written.

Config

A .env or config file was malformed.

Fields

file: String

line: usize

message: String

Json

A JSON document could not be parsed.

Fields

line: usize

column: usize

message: String

Template

A template could not be parsed or rendered.

Carries the position because a view is written by hand, often by someone who is not the person reading the stack trace.

Fields

file: String

line: usize

column: usize

message: String

Protocol(String)

A malformed HTTP request reached the parser.

Unavailable(String)

A dependency was not tried, because it is known to be failing.

Distinct from a failure on purpose: nothing was sent, so nothing can have had an effect, and a caller may safely fall back to a cache, a default, or a degraded answer. Raised by the circuit breaker in rustlavel-client.

Message(String)

Anything raised by application code.

Implementations

impl Error

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

pub fn status(&self) -> u16

The HTTP status this error should surface as when it escapes a handler.

pub fn title(&self) -> &'static str

A short, human title for the dev error page.

pub fn hint(&self) -> Option<String>

A suggestion shown on the dev error page — the Ignition touch.

Trait Implementations

impl Debug for Error

Deliberately the same as Display.

Rust prints the error a main returns with Debug, not Display, so the derived form is what people actually see when an application fails to start. It reads like this:

Error: Io(Os { code: 48, kind: AddrInUse, message: "Address already in use" })

which names the struct that holds the problem rather than the problem, and tells somebody nothing they can act on. Delegating to Display gives them the sentence that was written for them instead. Test output improves for the same reason: unwrap_err() on a bad config now says which file and line, not which variant.

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

Formats the value using the given formatter.

impl Display for Error

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

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<&str> for Error

fn from(s: &str) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(e: Error) -> Self

Converts to this type from the input type.

impl From<String> for Error

fn from(s: String) -> Self

Converts to this type from the input type.