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//! Run with
//!
//! ```not_rust
//! cargo run -p example-validator
//!
//! curl '127.0.0.1:3000?name='
//! -> Input validation error: [name: Can not be empty]
//!
//! curl '127.0.0.1:3000?name=LT'
//! -> <h1>Hello, LT!</h1>
//! ```
use async_trait::async_trait;
use axum::{
extract::{rejection::FormRejection, Form, FromRequest, Request},
http::StatusCode,
response::{Html, IntoResponse, Response},
routing::get,
Router,
};
use serde::{de::DeserializeOwned, Deserialize};
use thiserror::Error;
use tokio::net::TcpListener;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
use validator::Validate;
#[tokio::main]
async fn main() {
tracing_subscriber::registry()
.with(
tracing_subscriber::EnvFilter::try_from_default_env()
.unwrap_or_else(|_| format!("{}=debug", env!("CARGO_CRATE_NAME")).into()),
)
.with(tracing_subscriber::fmt::layer())
.init();
// build our application with a route
let app = Router::new().route("/", get(handler));
// run it
let listener = TcpListener::bind("127.0.0.1:3000").await.unwrap();
tracing::debug!("listening on {}", listener.local_addr().unwrap());
axum::serve(listener, app).await.unwrap();
}
#[derive(Debug, Deserialize, Validate)]
pub struct NameInput {
#[validate(length(min = 1, message = "Can not be empty"))]
pub name: String,
}
async fn handler(ValidatedForm(input): ValidatedForm<NameInput>) -> Html<String> {
Html(format!("<h1>Hello, {}!</h1>", input.name))
}
#[derive(Debug, Clone, Copy, Default)]
pub struct ValidatedForm<T>(pub T);
#[async_trait]
impl<T, S> FromRequest<S> for ValidatedForm<T>
where
T: DeserializeOwned + Validate,
S: Send + Sync,
Form<T>: FromRequest<S, Rejection = FormRejection>,
{
type Rejection = ServerError;
async fn from_request(req: Request, state: &S) -> Result<Self, Self::Rejection> {
let Form(value) = Form::<T>::from_request(req, state).await?;
value.validate()?;
Ok(ValidatedForm(value))
}
}
#[derive(Debug, Error)]
pub enum ServerError {
#[error(transparent)]
ValidationError(#[from] validator::ValidationErrors),
#[error(transparent)]
AxumFormRejection(#[from] FormRejection),
}
impl IntoResponse for ServerError {
fn into_response(self) -> Response {
match self {
ServerError::ValidationError(_) => {
let message = format!("Input validation error: [{self}]").replace('\n', ", ");
(StatusCode::BAD_REQUEST, message)
}
ServerError::AxumFormRejection(_) => (StatusCode::BAD_REQUEST, self.to_string()),
}
.into_response()
}
}
|
