add support for private network access cors header

closes #294

actix-cors/CHANGES.md

@@ -1,6 +1,7 @@
 # Changes
 
 ## Unreleased - 2022-xx-xx
+- Add `Cors::allow_private_network_access()` behind an unstable flag (`draft-private-network-access`). [#297]
 
 
 ## 0.6.3 - 2022-09-21

actix-cors/Cargo.toml

@@ -12,9 +12,12 @@ repository = "https://github.com/actix/actix-extras.git"
 license = "MIT OR Apache-2.0"
 edition = "2018"
 
-[lib]
-name = "actix_cors"
-path = "src/lib.rs"
+[package.metadata.docs.rs]
+rustdoc-args = ["--cfg", "docsrs"]
+all-features = true
+
+[features]
+draft-private-network-access = []
 
 [dependencies]
 actix-utils = "3"

actix-cors/src/builder.rs

@@ -101,6 +101,8 @@ impl Cors {
             preflight: true,
             send_wildcard: false,
             supports_credentials: true,
+            #[cfg(feature = "draft-private-network-access")]
+            allow_private_network_access: false,
             vary_header: true,
             block_on_origin_mismatch: true,
         };
@@ -370,7 +372,7 @@ impl Cors {
     /// [Fetch Standard CORS protocol]: https://fetch.spec.whatwg.org/#http-cors-protocol
     pub fn max_age(mut self, max_age: impl Into<Option<usize>>) -> Cors {
         if let Some(cors) = cors(&mut self.inner, &self.error) {
-            cors.max_age = max_age.into()
+            cors.max_age = max_age.into();
         }
 
         self
@@ -389,7 +391,7 @@ impl Cors {
     /// Defaults to `false`.
     pub fn send_wildcard(mut self) -> Cors {
         if let Some(cors) = cors(&mut self.inner, &self.error) {
-            cors.send_wildcard = true
+            cors.send_wildcard = true;
         }
 
         self
@@ -412,7 +414,27 @@ impl Cors {
     /// [Fetch Standard CORS protocol]: https://fetch.spec.whatwg.org/#http-cors-protocol
     pub fn supports_credentials(mut self) -> Cors {
         if let Some(cors) = cors(&mut self.inner, &self.error) {
-            cors.supports_credentials = true
+            cors.supports_credentials = true;
+        }
+
+        self
+    }
+
+    /// Allow private network access.
+    ///
+    /// If true, injects the `Access-Control-Allow-Private-Network: true` header in responses if the
+    /// request contained the `Access-Control-Request-Private-Network: true` header.
+    ///
+    /// For more information on this behavior, see the draft [Private Network Access] spec.
+    ///
+    /// Defaults to `false`.
+    ///
+    /// [Private Network Access]: https://wicg.github.io/private-network-access
+    #[cfg(feature = "draft-private-network-access")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "draft-private-network-access")))]
+    pub fn allow_private_network_access(mut self) -> Cors {
+        if let Some(cors) = cors(&mut self.inner, &self.error) {
+            cors.allow_private_network_access = true;
         }
 
         self
@@ -430,7 +452,7 @@ impl Cors {
     /// By default, `Vary` header support is enabled.
     pub fn disable_vary_header(mut self) -> Cors {
         if let Some(cors) = cors(&mut self.inner, &self.error) {
-            cors.vary_header = false
+            cors.vary_header = false;
         }
 
         self
@@ -444,7 +466,7 @@ impl Cors {
     /// By default *preflight* support is enabled.
     pub fn disable_preflight(mut self) -> Cors {
         if let Some(cors) = cors(&mut self.inner, &self.error) {
-            cors.preflight = false
+            cors.preflight = false;
         }
 
         self
@@ -462,7 +484,7 @@ impl Cors {
     /// Defaults to `true`.
     pub fn block_on_origin_mismatch(mut self, block: bool) -> Cors {
         if let Some(cors) = cors(&mut self.inner, &self.error) {
-            cors.block_on_origin_mismatch = block
+            cors.block_on_origin_mismatch = block;
         }
 
         self
@@ -492,6 +514,8 @@ impl Default for Cors {
             preflight: true,
             send_wildcard: false,
             supports_credentials: false,
+            #[cfg(feature = "draft-private-network-access")]
+            allow_private_network_access: false,
             vary_header: true,
             block_on_origin_mismatch: true,
         };

actix-cors/src/inner.rs

@@ -64,6 +64,8 @@ pub(crate) struct Inner {
     pub(crate) preflight: bool,
     pub(crate) send_wildcard: bool,
     pub(crate) supports_credentials: bool,
+    #[cfg(feature = "draft-private-network-access")]
+    pub(crate) allow_private_network_access: bool,
     pub(crate) vary_header: bool,
     pub(crate) block_on_origin_mismatch: bool,
 }
@@ -219,8 +221,20 @@ pub(crate) fn add_vary_header(headers: &mut HeaderMap) {
             let mut val: Vec<u8> = Vec::with_capacity(hdr.len() + 71);
             val.extend(hdr.as_bytes());
             val.extend(b", Origin, Access-Control-Request-Method, Access-Control-Request-Headers");
+
+            #[cfg(feature = "draft-private-network-access")]
+            val.extend(b", Access-Control-Allow-Private-Network");
+
             val.try_into().unwrap()
         }
+
+        #[cfg(feature = "draft-private-network-access")]
+        None => HeaderValue::from_static(
+            "Origin, Access-Control-Request-Method, Access-Control-Request-Headers, \
+            Access-Control-Allow-Private-Network",
+        ),
+
+        #[cfg(not(feature = "draft-private-network-access"))]
         None => HeaderValue::from_static(
             "Origin, Access-Control-Request-Method, Access-Control-Request-Headers",
         ),

actix-cors/src/lib.rs

@@ -1,11 +1,16 @@
 //! Cross-Origin Resource Sharing (CORS) controls for Actix Web.
 //!
-//! This middleware can be applied to both applications and resources. Once built, a
-//! [`Cors`] builder can be used as an argument for Actix Web's `App::wrap()`,
-//! `Scope::wrap()`, or `Resource::wrap()` methods.
+//! This middleware can be applied to both applications and resources. Once built, a [`Cors`]
+//! builder can be used as an argument for Actix Web's `App::wrap()`, `Scope::wrap()`, or
+//! `Resource::wrap()` methods.
 //!
 //! This CORS middleware automatically handles `OPTIONS` preflight requests.
 //!
+//! # Crate Features
+//! - `draft-private-network-access`: ⚠️ Unstable. Adds opt-in support for the [Private Network
+//!   Access] spec extensions. This feature is unstable since it will follow any breaking changes in
+//!   the draft spec until it is finalized.
+//!
 //! # Example
 //! ```no_run
 //! use actix_cors::Cors;
@@ -40,12 +45,15 @@
 //!     Ok(())
 //! }
 //! ```
+//!
+//! [Private Network Access]: https://wicg.github.io/private-network-access
 
 #![forbid(unsafe_code)]
 #![deny(rust_2018_idioms, nonstandard_style)]
 #![warn(future_incompatible, missing_docs, missing_debug_implementations)]
 #![doc(html_logo_url = "https://actix.rs/img/logo.png")]
 #![doc(html_favicon_url = "https://actix.rs/favicon.ico")]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 mod all_or_some;
 mod builder;

actix-cors/src/middleware.rs

@@ -93,6 +93,18 @@ impl<S> CorsMiddleware<S> {
             res.insert_header((header::ACCESS_CONTROL_ALLOW_HEADERS, headers.clone()));
         }
 
+        #[cfg(feature = "draft-private-network-access")]
+        if inner.allow_private_network_access
+            && req
+                .headers()
+                .contains_key("access-control-request-private-network")
+        {
+            res.insert_header((
+                header::HeaderName::from_static("access-control-allow-private-network"),
+                HeaderValue::from_static("true"),
+            ));
+        }
+
         if inner.supports_credentials {
             res.insert_header((
                 header::ACCESS_CONTROL_ALLOW_CREDENTIALS,
@@ -162,6 +174,19 @@ impl<S> CorsMiddleware<S> {
             );
         }
 
+        #[cfg(feature = "draft-private-network-access")]
+        if inner.allow_private_network_access
+            && res
+                .request()
+                .headers()
+                .contains_key("access-control-request-private-network")
+        {
+            res.headers_mut().insert(
+                header::HeaderName::from_static("access-control-allow-private-network"),
+                HeaderValue::from_static("true"),
+            );
+        }
+
         if inner.vary_header {
             add_vary_header(res.headers_mut());
         }

actix-cors/tests/tests.rs

@@ -264,10 +264,16 @@ async fn test_response() {
             .get(header::ACCESS_CONTROL_ALLOW_ORIGIN)
             .map(HeaderValue::as_bytes)
     );
+    #[cfg(not(feature = "draft-private-network-access"))]
     assert_eq!(
         resp.headers().get(header::VARY).map(HeaderValue::as_bytes),
         Some(&b"Origin, Access-Control-Request-Method, Access-Control-Request-Headers"[..]),
     );
+    #[cfg(feature = "draft-private-network-access")]
+    assert_eq!(
+        resp.headers().get(header::VARY).map(HeaderValue::as_bytes),
+        Some(&b"Origin, Access-Control-Request-Method, Access-Control-Request-Headers, Access-Control-Allow-Private-Network"[..]),
+    );
 
     #[allow(clippy::needless_collect)]
     {
@@ -311,9 +317,18 @@ async fn test_response() {
         .method(Method::OPTIONS)
         .to_srv_request();
     let resp = test::call_service(&cors, req).await;
+    #[cfg(not(feature = "draft-private-network-access"))]
     assert_eq!(
-        resp.headers().get(header::VARY).map(HeaderValue::as_bytes),
-        Some(&b"Accept, Origin, Access-Control-Request-Method, Access-Control-Request-Headers"[..]),
+        resp.headers()
+            .get(header::VARY)
+            .map(HeaderValue::as_bytes)
+            .unwrap(),
+        b"Accept, Origin, Access-Control-Request-Method, Access-Control-Request-Headers",
+    );
+    #[cfg(feature = "draft-private-network-access")]
+    assert_eq!(
+        resp.headers().get(header::VARY).map(HeaderValue::as_bytes).unwrap(),
+        b"Accept, Origin, Access-Control-Request-Method, Access-Control-Request-Headers, Access-Control-Allow-Private-Network",
     );
 
     let cors = Cors::default()
@@ -463,6 +478,7 @@ async fn vary_header_on_all_handled_responses() {
     assert!(resp
         .headers()
         .contains_key(header::ACCESS_CONTROL_ALLOW_METHODS));
+    #[cfg(not(feature = "draft-private-network-access"))]
     assert_eq!(
         resp.headers()
             .get(header::VARY)
@@ -471,6 +487,15 @@ async fn vary_header_on_all_handled_responses() {
             .unwrap(),
         "Origin, Access-Control-Request-Method, Access-Control-Request-Headers",
     );
+    #[cfg(feature = "draft-private-network-access")]
+    assert_eq!(
+        resp.headers()
+            .get(header::VARY)
+            .expect("response should have Vary header")
+            .to_str()
+            .unwrap(),
+        "Origin, Access-Control-Request-Method, Access-Control-Request-Headers, Access-Control-Allow-Private-Network",
+    );
 
     // follow-up regular request
     let req = TestRequest::default()
@@ -479,6 +504,7 @@ async fn vary_header_on_all_handled_responses() {
         .to_srv_request();
     let resp = test::call_service(&cors, req).await;
     assert_eq!(resp.status(), StatusCode::OK);
+    #[cfg(not(feature = "draft-private-network-access"))]
     assert_eq!(
         resp.headers()
             .get(header::VARY)
@@ -487,6 +513,15 @@ async fn vary_header_on_all_handled_responses() {
             .unwrap(),
         "Origin, Access-Control-Request-Method, Access-Control-Request-Headers",
     );
+    #[cfg(feature = "draft-private-network-access")]
+    assert_eq!(
+        resp.headers()
+            .get(header::VARY)
+            .expect("response should have Vary header")
+            .to_str()
+            .unwrap(),
+        "Origin, Access-Control-Request-Method, Access-Control-Request-Headers, Access-Control-Allow-Private-Network",
+    );
 
     let cors = Cors::default()
         .allow_any_method()
@@ -501,6 +536,7 @@ async fn vary_header_on_all_handled_responses() {
         .to_srv_request();
     let resp = test::call_service(&cors, req).await;
     assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
+    #[cfg(not(feature = "draft-private-network-access"))]
     assert_eq!(
         resp.headers()
             .get(header::VARY)
@@ -509,11 +545,21 @@ async fn vary_header_on_all_handled_responses() {
             .unwrap(),
         "Origin, Access-Control-Request-Method, Access-Control-Request-Headers",
     );
+    #[cfg(feature = "draft-private-network-access")]
+    assert_eq!(
+        resp.headers()
+            .get(header::VARY)
+            .expect("response should have Vary header")
+            .to_str()
+            .unwrap(),
+        "Origin, Access-Control-Request-Method, Access-Control-Request-Headers, Access-Control-Allow-Private-Network",
+    );
 
     // regular request no origin
     let req = TestRequest::default().method(Method::PUT).to_srv_request();
     let resp = test::call_service(&cors, req).await;
     assert_eq!(resp.status(), StatusCode::OK);
+    #[cfg(not(feature = "draft-private-network-access"))]
     assert_eq!(
         resp.headers()
             .get(header::VARY)
@@ -522,6 +568,15 @@ async fn vary_header_on_all_handled_responses() {
             .unwrap(),
         "Origin, Access-Control-Request-Method, Access-Control-Request-Headers",
     );
+    #[cfg(feature = "draft-private-network-access")]
+    assert_eq!(
+        resp.headers()
+            .get(header::VARY)
+            .expect("response should have Vary header")
+            .to_str()
+            .unwrap(),
+        "Origin, Access-Control-Request-Method, Access-Control-Request-Headers, Access-Control-Allow-Private-Network",
+    );
 }
 
 #[actix_web::test]
@@ -578,3 +633,42 @@ async fn expose_all_request_header_values() {
     assert!(cd_hdr.contains("content-disposition"));
     assert!(cd_hdr.contains("access-control-allow-origin"));
 }
+
+#[cfg(feature = "draft-private-network-access")]
+#[actix_web::test]
+async fn private_network_access() {
+    let cors = Cors::permissive()
+        .allowed_origin("https://public.site")
+        .allow_private_network_access()
+        .new_transform(fn_service(|req: ServiceRequest| async move {
+            let res = req.into_response(
+                HttpResponse::Ok()
+                    .insert_header((header::CONTENT_DISPOSITION, "test disposition"))
+                    .finish(),
+            );
+
+            Ok(res)
+        }))
+        .await
+        .unwrap();
+
+    let req = TestRequest::default()
+        .insert_header((header::ORIGIN, "https://public.site"))
+        .insert_header((header::ACCESS_CONTROL_REQUEST_METHOD, "POST"))
+        .insert_header((header::ACCESS_CONTROL_ALLOW_CREDENTIALS, "true"))
+        .to_srv_request();
+    let res = test::call_service(&cors, req).await;
+    assert!(res.headers().contains_key("access-control-allow-origin"));
+
+    let req = TestRequest::default()
+        .insert_header((header::ORIGIN, "https://public.site"))
+        .insert_header((header::ACCESS_CONTROL_REQUEST_METHOD, "POST"))
+        .insert_header((header::ACCESS_CONTROL_ALLOW_CREDENTIALS, "true"))
+        .insert_header(("Access-Control-Request-Private-Network", "true"))
+        .to_srv_request();
+    let res = test::call_service(&cors, req).await;
+    assert!(res.headers().contains_key("access-control-allow-origin"));
+    assert!(res
+        .headers()
+        .contains_key("access-control-allow-private-network"));
+}