axum/examples/anyhow-error-response/src/main.rs

//! Run with
//!
//! ```not_rust
//! cd examples && cargo run -p example-anyhow-error-response
//! ```

use axum::{
    http::StatusCode,
    response::{IntoResponse, Response},
    routing::get,
    Router,
};
use std::net::SocketAddr;

#[tokio::main]
async fn main() {
    let app = Router::new().route("/", get(handler));

    let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
    println!("listening on {}", addr);
    axum::Server::bind(&addr)
        .serve(app.into_make_service())
        .await
        .unwrap();
}

async fn handler() -> Result<(), AppError> {
    try_thing()?;
    Ok(())
}

fn try_thing() -> Result<(), anyhow::Error> {
    anyhow::bail!("it failed!")
}

// Make our own error that wraps `anyhow::Error`.
struct AppError(anyhow::Error);

// Tell axum how to convert `AppError` into a response.
impl IntoResponse for AppError {
    fn into_response(self) -> Response {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            format!("Something went wrong: {}", self.0),
        )
            .into_response()
    }
}

// This enables using `?` on functions that return `Result<_, anyhow::Error>` to turn them into
// `Result<_, AppError>`. That way you don't need to do that manually.
impl<E> From<E> for AppError
where
    E: Into<anyhow::Error>,
{
    fn from(err: E) -> Self {
        Self(err.into())
    }
}