actix-website/examples/errors/src/override_error.rs

use actix_web::{web, App};
// <override>
use actix_web::{error, http, HttpRequest, HttpResponse};
use failure::Fail;

#[derive(Fail, Debug)]
enum MyError {
    #[fail(display = "internal error")]
    InternalError,
    #[fail(display = "bad request")]
    BadClientData,
    #[fail(display = "timeout")]
    Timeout,
}

impl error::ResponseError for MyError {
    fn error_response(&self) -> HttpResponse {
        match *self {
            MyError::InternalError => {
                HttpResponse::new(http::StatusCode::INTERNAL_SERVER_ERROR)
            }
            MyError::BadClientData => HttpResponse::new(http::StatusCode::BAD_REQUEST),
            MyError::Timeout => HttpResponse::new(http::StatusCode::GATEWAY_TIMEOUT),
        }
    }
}

fn index(_req: HttpRequest) -> Result<&'static str, MyError> {
    Err(MyError::BadClientData)
}
// </override>
pub fn main() {
    App::new()
        .route("/", web::get().to(index))
        .route("/e2", web::get().to(error2))
        .route("/e3", web::get().to(error3));
}

fn error2(_req: HttpRequest) -> Result<&'static str, MyError> {
    Err(MyError::InternalError)
}

fn error3(_req: HttpRequest) -> Result<&'static str, MyError> {
    Err(MyError::Timeout)
}