Make () and None return a HTTP 204 response instead of 200

axum-core/src/response/into_response.rs

@@ -116,15 +116,15 @@ pub trait IntoResponse {
 
 impl IntoResponse for StatusCode {
     fn into_response(self) -> Response {
-        let mut res = ().into_response();
+        let mut res = Body::empty().into_response();
         *res.status_mut() = self;
         res
     }
 }
 
 impl IntoResponse for () {
     fn into_response(self) -> Response {
-        Body::empty().into_response()
+        StatusCode::NO_CONTENT.into_response()
     }
 }
 

axum-extra/src/json_lines.rs

@@ -226,7 +226,7 @@ mod tests {
             )
             .send()
             .await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[tokio::test]

axum-extra/src/routing/mod.rs

@@ -353,14 +353,14 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
 
         let res = client.get("/foo/").send().await;
         assert_eq!(res.status(), StatusCode::PERMANENT_REDIRECT);
         assert_eq!(res.headers()["location"], "/foo");
 
         let res = client.get("/bar/").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
 
         let res = client.get("/bar").send().await;
         assert_eq!(res.status(), StatusCode::PERMANENT_REDIRECT);

axum/src/extract/connect_info.rs

@@ -197,7 +197,7 @@ axum_core::__impl_deref!(ConnectInfo);
 ///
 ///     let request = Request::new(Body::empty());
 ///     let response = app.oneshot(request).await.unwrap();
-///     assert_eq!(response.status(), StatusCode::OK);
+///     assert_eq!(response.status(), StatusCode::NO_CONTENT);
 /// }
 /// #
 /// # #[tokio::main]

axum/src/extract/matched_path.rs

@@ -205,7 +205,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo/bar").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -225,7 +225,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo/bar").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -242,7 +242,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo/bar").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[tokio::test]
@@ -259,7 +259,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo/bar").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -279,7 +279,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo/bar").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -300,7 +300,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo/bar").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -314,7 +314,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo/bar").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     // https://github.com/tokio-rs/axum/issues/1579
@@ -334,7 +334,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -349,6 +349,6 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo/bar").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 }

axum/src/extract/nested_path.rs

@@ -136,7 +136,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/api/users").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -154,7 +154,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/api/users").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -172,7 +172,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/api/v2/users").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -190,7 +190,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/api/v2/users").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -208,7 +208,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/users").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -226,7 +226,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/api/users").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -241,7 +241,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/api/doesnt-exist").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -260,6 +260,6 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/api/users").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 }

axum/src/extract/path/mod.rs

@@ -557,10 +557,10 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/users/42").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
 
         let res = client.post("/users/1337").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -570,7 +570,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/users/42").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -641,7 +641,7 @@ mod tests {
         assert_eq!(res.status(), StatusCode::NOT_FOUND);
 
         let res = client.get("/foo").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]
@@ -759,7 +759,7 @@ mod tests {
         let client = TestClient::new(app);
 
         let res = client.get("/foo/bar").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[crate::test]

axum/src/extract/request_parts.rs

@@ -110,6 +110,6 @@ mod tests {
         let client = TestClient::new(Router::new().route("/", get(handler)).layer(Extension(Ext)));
 
         let res = client.get("/").header("x-foo", "123").send().await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 }

axum/src/extract/ws.rs

@@ -858,7 +858,7 @@ mod tests {
 
         let res = svc.oneshot(req).await.unwrap();
 
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     #[allow(dead_code)]

axum/src/json.rs

@@ -263,7 +263,7 @@ mod tests {
                 .send()
                 .await;
 
-            res.status() == StatusCode::OK
+            res.status() == StatusCode::NO_CONTENT
         }
 
         assert!(valid_json_content_type("application/json").await);

axum/src/middleware/from_extractor.rs

@@ -360,7 +360,7 @@ mod tests {
             .header(http::header::AUTHORIZATION, "secret")
             .send()
             .await;
-        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.status(), StatusCode::NO_CONTENT);
     }
 
     // just needs to compile

axum/src/response/mod.rs

@@ -63,6 +63,7 @@ impl<T> From<T> for Html<T> {
 #[cfg(test)]
 mod tests {
     use crate::extract::Extension;
+    use crate::test_helpers::TestClient;
     use crate::{routing::get, Router};
     use axum_core::response::IntoResponse;
     use http::HeaderMap;
@@ -224,4 +225,14 @@ mod tests {
             .route("/", get(header_array_extension_body))
             .route("/", get(header_array_extension_mixed_body));
     }
+
+    #[tokio::test]
+    async fn test_unit_http204_response() {
+        async fn unit() {} // returns the unit () value
+
+        let app = Router::new().route("/unit", get(unit));
+        let client = TestClient::new(app);
+        let res = client.get("/unit").send().await;
+        assert_eq!(res.status(), StatusCode::NO_CONTENT)
+    }
 }

axum/src/routing/tests/fallback.rs

@@ -9,7 +9,10 @@ async fn basic() {
 
     let client = TestClient::new(app);
 
-    assert_eq!(client.get("/foo").send().await.status(), StatusCode::OK);
+    assert_eq!(
+        client.get("/foo").send().await.status(),
+        StatusCode::NO_CONTENT
+    );
 
     let res = client.get("/does-not-exist").send().await;
     assert_eq!(res.status(), StatusCode::OK);
@@ -24,7 +27,10 @@ async fn nest() {
 
     let client = TestClient::new(app);
 
-    assert_eq!(client.get("/foo/bar").send().await.status(), StatusCode::OK);
+    assert_eq!(
+        client.get("/foo/bar").send().await.status(),
+        StatusCode::NO_CONTENT
+    );
 
     let res = client.get("/does-not-exist").send().await;
     assert_eq!(res.status(), StatusCode::OK);
@@ -40,8 +46,14 @@ async fn or() {
 
     let client = TestClient::new(app);
 
-    assert_eq!(client.get("/one").send().await.status(), StatusCode::OK);
-    assert_eq!(client.get("/two").send().await.status(), StatusCode::OK);
+    assert_eq!(
+        client.get("/one").send().await.status(),
+        StatusCode::NO_CONTENT
+    );
+    assert_eq!(
+        client.get("/two").send().await.status(),
+        StatusCode::NO_CONTENT
+    );
 
     let res = client.get("/does-not-exist").send().await;
     assert_eq!(res.status(), StatusCode::OK);
@@ -195,7 +207,7 @@ async fn doesnt_panic_if_used_with_nested_router() {
     let client = TestClient::new(routes_all);
 
     let res = client.get("/foobar").send().await;
-    assert_eq!(res.status(), StatusCode::OK);
+    assert_eq!(res.status(), StatusCode::NO_CONTENT);
 }
 
 #[crate::test]