Implement OptionalFromRequestParts for axum-extra's Query<T>

… and deprecate OptionalQuery.

axum-extra/src/extract/mod.rs

@@ -36,7 +36,10 @@ pub use self::cookie::SignedCookieJar;
 pub use self::form::{Form, FormRejection};
 
 #[cfg(feature = "query")]
-pub use self::query::{OptionalQuery, OptionalQueryRejection, Query, QueryRejection};
+#[allow(deprecated)]
+pub use self::query::OptionalQuery;
+#[cfg(feature = "query")]
+pub use self::query::{OptionalQueryRejection, Query, QueryRejection};
 
 #[cfg(feature = "multipart")]
 pub use self::multipart::Multipart;

axum-extra/src/extract/query.rs

@@ -1,6 +1,6 @@
 use axum::{
     async_trait,
-    extract::FromRequestParts,
+    extract::{FromRequestParts, OptionalFromRequestParts},
     response::{IntoResponse, Response},
     Error,
 };
@@ -71,6 +71,28 @@ where
     }
 }
 
+#[async_trait]
+impl<T, S> OptionalFromRequestParts<S> for Query<T>
+where
+    T: DeserializeOwned,
+    S: Send + Sync,
+{
+    type Rejection = QueryRejection;
+
+    async fn from_request_parts(
+        parts: &mut Parts,
+        _state: &S,
+    ) -> Result<Option<Self>, Self::Rejection> {
+        if let Some(query) = parts.uri.query() {
+            let value = serde_html_form::from_str(query)
+                .map_err(|err| QueryRejection::FailedToDeserializeQueryString(Error::new(err)))?;
+            Ok(Some(Self(value)))
+        } else {
+            Ok(None)
+        }
+    }
+}
+
 axum_core::__impl_deref!(Query);
 
 /// Rejection used for [`Query`].
@@ -152,9 +174,11 @@ impl std::error::Error for QueryRejection {
 ///
 /// [example]: https://github.com/tokio-rs/axum/blob/main/examples/query-params-with-empty-strings/src/main.rs
 #[cfg_attr(docsrs, doc(cfg(feature = "query")))]
+#[deprecated = "Use Option<Path<_>> instead"]
 #[derive(Debug, Clone, Copy, Default)]
 pub struct OptionalQuery<T>(pub Option<T>);
 
+#[allow(deprecated)]
 #[async_trait]
 impl<T, S> FromRequestParts<S> for OptionalQuery<T>
 where
@@ -175,6 +199,7 @@ where
     }
 }
 
+#[allow(deprecated)]
 impl<T> std::ops::Deref for OptionalQuery<T> {
     type Target = Option<T>;
 
@@ -184,6 +209,7 @@ impl<T> std::ops::Deref for OptionalQuery<T> {
     }
 }
 
+#[allow(deprecated)]
 impl<T> std::ops::DerefMut for OptionalQuery<T> {
     #[inline]
     fn deref_mut(&mut self) -> &mut Self::Target {
@@ -231,6 +257,7 @@ impl std::error::Error for OptionalQueryRejection {
 }
 
 #[cfg(test)]
+#[allow(deprecated)]
 mod tests {
     use super::*;
     use crate::test_helpers::*;