axum - v0.5.0

• added: Document sharing state between handler and middleware (#783)

• added: Extension<_> can now be used in tuples for building responses, and will set an
  extension on the response (#797)

• added: extract::Host for extracting the hostname of a request (#827)

• added: Add IntoResponseParts trait which allows defining custom response
  types for adding headers or extensions to responses (#797)

• added: TypedHeader implements the new IntoResponseParts trait so they
  can be returned from handlers as parts of a response (#797)

• changed: Router::merge now accepts Into<Router> (#819)

• breaking: sse::Event now accepts types implementing AsRef<str> instead of Into<String>
  as field values.

• breaking: sse::Event now panics if a setter method is called twice instead of silently
  overwriting old values.

• breaking: Require Output = () on WebSocketStream::on_upgrade (#644)

• breaking: Make TypedHeaderRejectionReason #[non_exhaustive] (#665)

• breaking: Using HeaderMap as an extractor will no longer remove the headers and thus
  they'll still be accessible to other extractors, such as axum::extract::Json. Instead
  HeaderMap will clone the headers. You should prefer to use TypedHeader to extract only the
  headers you need (#698)

  This includes these breaking changes:

  • RequestParts::take_headers has been removed.
  • RequestParts::headers returns &HeaderMap.
  • RequestParts::headers_mut returns &mut HeaderMap.
  • HeadersAlreadyExtracted has been removed.
  • The HeadersAlreadyExtracted variant has been removed from these rejections:
    • RequestAlreadyExtracted
    • RequestPartsAlreadyExtracted
    • JsonRejection
    • FormRejection
    • ContentLengthLimitRejection
    • WebSocketUpgradeRejection
  • <HeaderMap as FromRequest<_>>::Rejection has been changed to std::convert::Infallible.

• breaking: axum::http::Extensions is no longer an extractor (ie it
  doesn't implement FromRequest). The axum::extract::Extension extractor is
  not impacted by this and works the same. This change makes it harder to
  accidentally remove all extensions which would result in confusing errors
  elsewhere (#699)
  This includes these breaking changes:

  • RequestParts::take_extensions has been removed.
  • RequestParts::extensions returns &Extensions.
  • RequestParts::extensions_mut returns &mut Extensions.
  • RequestAlreadyExtracted has been removed.
  • <Request as FromRequest>::Rejection is now BodyAlreadyExtracted.
  • <http::request::Parts as FromRequest>::Rejection is now Infallible.
  • ExtensionsAlreadyExtracted has been removed.
  • The ExtensionsAlreadyExtracted removed variant has been removed from these rejections:
    • ExtensionRejection
    • PathRejection
    • MatchedPathRejection
    • WebSocketUpgradeRejection

• breaking: Redirect::found has been removed (#800)

• breaking: AddExtensionLayer has been removed. Use Extension instead. It now implements
  tower::Layer (#807)

• breaking: AddExtension has been moved from the root module to middleware

• breaking: .nest("/foo/", Router::new().route("/bar", _)) now does the right thing and
  results in a route at /foo/bar instead of /foo//bar (#824)

• breaking: Routes are now required to start with /. Previously routes such as :foo would
  be accepted but most likely result in bugs (#823)

• breaking: Headers has been removed. Arrays of tuples directly implement
  IntoResponseParts so ([("x-foo", "foo")], response) now works (#797)

• breaking: InvalidJsonBody has been replaced with JsonDataError to clearly signal that the
  request body was syntactically valid JSON but couldn't be deserialized into the target type

• breaking: Handler is no longer an #[async_trait] but instead has an
  associated Future type. That allows users to build their own Handler types
  without paying the cost of #[async_trait] (#879)

• changed: New JsonSyntaxError variant added to JsonRejection. This is returned when the
  request body contains syntactically invalid JSON

• fixed: Correctly set the Content-Length header for response to HEAD
  requests (#734)

• fixed: Fix wrong content-length for HEAD requests to endpoints that returns chunked
  responses (#755)

• fixed: Fixed several routing bugs related to nested "opaque" tower services (i.e.
  non-Router services) (#841 and #842)

• changed: Update to tokio-tungstenite 0.17 (#791)

• breaking: Redirect::{to, temporary, permanent} now accept &str instead
  of Uri (#889)

• breaking: Remove second type parameter from Router::into_make_service_with_connect_info
  and Handler::into_make_service_with_connect_info to support MakeServices
  that accept multiple targets (#892)