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use axum::{
extract::Request,
http::StatusCode,
response::{IntoResponse, Response},
};
use std::pin::Pin;
use std::task::{Context, Poll};
use tower::Service;
use crate::{app::App, error::Internal};
const UNAVAILABLE: (StatusCode, &str) = (
StatusCode::SERVICE_UNAVAILABLE,
"initial setup not completed",
);
#[derive(Clone)]
pub struct Layer<F> {
app: App,
fallback: F,
}
impl Layer<(StatusCode, &'static str)> {
pub fn or_unavailable(app: App) -> Self {
Self::with_fallback(app, UNAVAILABLE)
}
}
impl<F> Layer<F> {
pub fn with_fallback(app: App, fallback: F) -> Self {
Layer { app, fallback }
}
}
impl<S, F> tower::Layer<S> for Layer<F>
where
Self: Clone,
{
type Service = Middleware<S, F>;
fn layer(&self, inner: S) -> Self::Service {
let Self { app, fallback } = self.clone();
Middleware {
inner,
app,
fallback,
}
}
}
#[derive(Clone)]
pub struct Middleware<S, F> {
inner: S,
app: App,
fallback: F,
}
impl<S, F> Service<Request> for Middleware<S, F>
where
Self: Clone,
S: Service<Request, Response = Response> + Send + 'static,
S::Future: Send,
F: IntoResponse + Clone + Send + 'static,
{
type Response = S::Response;
type Error = S::Error;
type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;
fn poll_ready(&mut self, ctx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.inner.poll_ready(ctx)
}
fn call(&mut self, req: Request) -> Self::Future {
let Self {
mut inner,
app,
fallback,
} = self.clone();
Box::pin(async move {
match app.setup().completed().await {
Ok(true) => inner.call(req).await,
Ok(false) => Ok(fallback.into_response()),
Err(error) => Ok(Internal::from(error).into_response()),
}
})
}
}
|
