Add Either{2..8} to axum-extra (#1263)

* Add `Either{2..8}`

* Apply suggestions from code review

Co-authored-by: Jonas Platte <[email protected]>

* Either2 => Either

* Update axum-extra/src/either.rs

Co-authored-by: Jonas Platte <[email protected]>

Co-authored-by: Jonas Platte <[email protected]>

axum-extra/src/lib.rs

@@ -63,13 +63,8 @@
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
 #![cfg_attr(test, allow(clippy::float_cmp))]
 
-use axum::{
-    async_trait,
-    extract::{FromRequest, RequestParts},
-    response::IntoResponse,
-};
-
 pub mod body;
+pub mod either;
 pub mod extract;
 pub mod handler;
 pub mod response;
@@ -81,46 +76,6 @@ pub mod json_lines;
 #[cfg(feature = "protobuf")]
 pub mod protobuf;
 
-/// Combines two extractors or responses into a single type.
-#[derive(Debug, Copy, Clone)]
-pub enum Either<L, R> {
-    /// A value of type L.
-    Left(L),
-    /// A value of type R.
-    Right(R),
-}
-
-#[async_trait]
-impl<L, R, B> FromRequest<B> for Either<L, R>
-where
-    L: FromRequest<B>,
-    R: FromRequest<B>,
-    B: Send,
-{
-    type Rejection = R::Rejection;
-
-    async fn from_request(req: &mut RequestParts<B>) -> Result<Self, Self::Rejection> {
-        if let Ok(l) = req.extract().await {
-            return Ok(Either::Left(l));
-        }
-
-        Ok(Either::Right(req.extract().await?))
-    }
-}
-
-impl<L, R> IntoResponse for Either<L, R>
-where
-    L: IntoResponse,
-    R: IntoResponse,
-{
-    fn into_response(self) -> axum::response::Response {
-        match self {
-            Self::Left(inner) => inner.into_response(),
-            Self::Right(inner) => inner.into_response(),
-        }
-    }
-}
-
 #[cfg(feature = "typed-routing")]
 #[doc(hidden)]
 pub mod __private {