pub struct Extension<T>(pub T);
Expand description
Extractor and response for extensions.
As extractor
This is commonly used to share state across handlers.
use axum::{
Router,
Extension,
routing::get,
};
use std::sync::Arc;
// Some shared state used throughout our application
struct State {
// ...
}
async fn handler(state: Extension<Arc<State>>) {
// ...
}
let state = Arc::new(State { /* ... */ });
let app = Router::new().route("/", get(handler))
// Add middleware that inserts the state into all incoming request's
// extensions.
.layer(Extension(state));
If the extension is missing it will reject the request with a 500 Internal Server Error
response.
As response
Response extensions can be used to share state with middleware.
use axum::{
Extension,
response::IntoResponse,
};
async fn handler() -> (Extension<Foo>, &'static str) {
(
Extension(Foo("foo")),
"Hello, World!"
)
}
#[derive(Clone)]
struct Foo(&'static str);
Tuple Fields
0: T
Trait Implementations
sourceimpl<T, S> FromRequestParts<S> for Extension<T>where
T: Clone + Send + Sync + 'static,
S: Send + Sync,
impl<T, S> FromRequestParts<S> for Extension<T>where
T: Clone + Send + Sync + 'static,
S: Send + Sync,
type Rejection = ExtensionRejection
type Rejection = ExtensionRejection
If the extractor fails it’ll use this “rejection” type. A rejection is
a kind of error that can be converted into a response. Read more
sourceimpl<T> IntoResponse for Extension<T>where
T: Send + Sync + 'static,
impl<T> IntoResponse for Extension<T>where
T: Send + Sync + 'static,
sourcefn into_response(self) -> Response
fn into_response(self) -> Response
Create a response.
sourceimpl<T> IntoResponseParts for Extension<T>where
T: Send + Sync + 'static,
impl<T> IntoResponseParts for Extension<T>where
T: Send + Sync + 'static,
type Error = Infallible
type Error = Infallible
The type returned in the event of an error. Read more
sourcefn into_response_parts(
self,
res: ResponseParts
) -> Result<ResponseParts, Self::Error>
fn into_response_parts(
self,
res: ResponseParts
) -> Result<ResponseParts, Self::Error>
Set parts of the response
impl<T: Copy> Copy for Extension<T>
Auto Trait Implementations
impl<T> RefUnwindSafe for Extension<T>where
T: RefUnwindSafe,
impl<T> Send for Extension<T>where
T: Send,
impl<T> Sync for Extension<T>where
T: Sync,
impl<T> Unpin for Extension<T>where
T: Unpin,
impl<T> UnwindSafe for Extension<T>where
T: UnwindSafe,
Blanket Implementations
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<S, B, T> FromRequest<S, B, ViaParts> for Twhere
B: 'static + Send,
S: Send + Sync,
T: FromRequestParts<S>,
impl<S, B, T> FromRequest<S, B, ViaParts> for Twhere
B: 'static + Send,
S: Send + Sync,
T: FromRequestParts<S>,
type Rejection = <T as FromRequestParts<S>>::Rejection
type Rejection = <T as FromRequestParts<S>>::Rejection
If the extractor fails it’ll use this “rejection” type. A rejection is
a kind of error that can be converted into a response. Read more