add some useful header name constants

actix-http/CHANGES.md

@@ -4,12 +4,20 @@
 ### Added
 - Implement `MessageBody` for `&mut B` where `B: MessageBody + Unpin`. [#2868]
 - Implement `MessageBody` for `Pin<B>` where `B::Target: MessageBody`. [#2868]
+- New header name constants in `header` module. [#????]
+  - `CROSS_ORIGIN_EMBEDDER_POLICY`
+  - `CROSS_ORIGIN_OPENER_POLICY`
+  - `PERMISSIONS_POLICY`
+  - `X_FORWARDED_FOR`
+  - `X_FORWARDED_HOST`
+  - `X_FORWARDED_PROTO`
 
 ### Performance
 - Improve overall performance of operations on `Extensions`. [#2890]
 
 [#2868]: https://github.com/actix/actix-web/pull/2868
 [#2890]: https://github.com/actix/actix-web/pull/2890
+[#????]: https://github.com/actix/actix-web/pull/????
 
 
 ## 3.2.2 - 2022-09-11

actix-http/src/header/mod.rs

@@ -1,5 +1,8 @@
 //! Pre-defined `HeaderName`s, traits for parsing and conversion, and other header utility methods.
 
+// declaring new header consts will yield this error
+#![allow(clippy::declare_interior_mutable_const)]
+
 use percent_encoding::{AsciiSet, CONTROLS};
 
 // re-export from http except header map related items
@@ -27,6 +30,21 @@ pub use http::header::{
     X_XSS_PROTECTION,
 };
 
+// other common headers not defined in `http`
+
+pub const CROSS_ORIGIN_EMBEDDER_POLICY: HeaderName =
+    HeaderName::from_static("cross-origin-embedder-policy");
+pub const CROSS_ORIGIN_OPENER_POLICY: HeaderName =
+    HeaderName::from_static("cross-origin-opener-policy");
+
+pub const PERMISSIONS_POLICY: HeaderName = HeaderName::from_static("permissions-policy");
+
+pub const X_FORWARDED_FOR: HeaderName = HeaderName::from_static("x-forwarded-for");
+pub const X_FORWARDED_HOST: HeaderName = HeaderName::from_static("x-forwarded-host");
+pub const X_FORWARDED_PROTO: HeaderName = HeaderName::from_static("x-forwarded-proto");
+
+// end other common headers
+
 use crate::{error::ParseError, HttpMessage};
 
 mod as_name;