add Created helper type

axum/src/response/mod.rs

@@ -82,6 +82,71 @@ impl IntoResponse for NoContent {
     }
 }
 
+/// A response with a 201 CREATED status
+///
+/// As 201 is recommended to come with a `Location` header referring to the location of the created
+/// object according to the RFC7231, using this struct can remind a user to do so.
+/// Remember that any IntoResponse struct used as an `inner` here may override the headers and status
+/// code set by this struct.
+#[derive(Clone, Debug)]
+pub struct Created<T: IntoResponse = ()> {
+    /// The value set for the `Location` header.
+    /// Existing location headers are not overwritten
+    location: Option<HeaderValue>,
+    inner: T,
+}
+impl Created {
+    #[must_use]
+    /// Creates a CREATED response with an empty body and no `Location` header
+    pub fn empty() -> Self {
+        Self {
+            location: None,
+            inner: (),
+        }
+    }
+    /// Creates a new `Created` with an empty body
+    pub fn empty_with_location(location: HeaderValue) -> Self {
+        Self {
+            location: Some(location),
+            inner: (),
+        }
+    }
+    /// Attaches a body to an empty `Created` response
+    pub fn with_body<T: IntoResponse>(self, body: T) -> Created<T> {
+        let Self {
+            location,
+            inner: (),
+        } = self;
+        Created {
+            location,
+            inner: body,
+        }
+    }
+}
+impl<T: IntoResponse> Created<T> {
+    /// Sets status and `Location` header along with the inner type's `IntoResponse` implementation.
+    /// Remember that the inner type may override headers and the status code.
+    pub fn new_with_location_header(body: T, location: HeaderValue) -> Self {
+        Self {
+            location: Some(location),
+            inner: body,
+        }
+    }
+}
+impl<T: IntoResponse> IntoResponse for Created<T> {
+    fn into_response(self) -> Response {
+        match self.location {
+            Some(l) => (
+                StatusCode::CREATED,
+                AppendHeaders([(http::header::LOCATION, l)]),
+                self.inner,
+            )
+                .into_response(),
+            None => (StatusCode::CREATED, self.inner).into_response(),
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::extract::Extension;