Implement `Deref` for extractors (#56)

Fixes https://github.com/tokio-rs/axum/issues/54

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Implement `Stream` for `WebSocket`.
 - Implement `Sink` for `WebSocket`.
+- Implement `Deref` most extractors.
 
 ## Breaking changes
 

src/extract/mod.rs

@@ -254,6 +254,7 @@ use serde::de::DeserializeOwned;
 use std::{
     collections::HashMap,
     convert::Infallible,
+    ops::Deref,
     pin::Pin,
     str::FromStr,
     task::{Context, Poll},
@@ -596,6 +597,14 @@ where
     }
 }
 
+impl<T> Deref for Query<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 /// Extractor that deserializes `application/x-www-form-urlencoded` requests
 /// into some type.
 ///
@@ -667,6 +676,14 @@ where
     }
 }
 
+impl<T> Deref for Form<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 /// Extractor that deserializes request bodies into some type.
 ///
 /// `T` is expected to implement [`serde::Deserialize`].
@@ -731,6 +748,14 @@ where
     }
 }
 
+impl<T> Deref for Json<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 fn has_content_type<B>(
     req: &RequestParts<B>,
     expected_content_type: &str,
@@ -809,6 +834,14 @@ where
     }
 }
 
+impl<T> Deref for Extension<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 #[async_trait]
 impl<B> FromRequest<B> for Bytes
 where
@@ -1071,6 +1104,14 @@ where
     }
 }
 
+impl<T, const N: u64> Deref for ContentLengthLimit<T, N> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 /// Extractor that will get captures from the URL.
 ///
 /// # Example
@@ -1219,6 +1260,14 @@ macro_rules! impl_parse_url {
 
 impl_parse_url!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16);
 
+impl<T> Deref for UrlParams<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 fn take_body<B>(req: &mut RequestParts<B>) -> Result<B, BodyAlreadyExtracted> {
     req.take_body().ok_or(BodyAlreadyExtracted)
 }
@@ -1274,6 +1323,16 @@ where
     }
 }
 
+#[cfg(feature = "headers")]
+#[cfg_attr(docsrs, doc(cfg(feature = "headers")))]
+impl<T> Deref for TypedHeader<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 /// Extractor that extracts the raw query string, without parsing it.
 ///
 /// # Example