Use constants for header names

tonic-build/src/server.rs

@@ -167,7 +167,7 @@ pub(crate) fn generate_internal<T: Service>(
                         _ => Box::pin(async move {
                             let mut response = http::Response::new(empty_body());
                             let headers = response.headers_mut();
-                            headers.insert("grpc-status", (tonic::Code::Unimplemented as i32).into());
+                            headers.insert(tonic::Status::GRPC_STATUS, (tonic::Code::Unimplemented as i32).into());
                             headers.insert(http::header::CONTENT_TYPE, tonic::metadata::GRPC_CONTENT_TYPE);
                             Ok(response)
                         }),

tonic-health/src/generated/grpc_health_v1.rs

@@ -423,7 +423,7 @@ pub mod health_server {
                         let headers = response.headers_mut();
                         headers
                             .insert(
-                                "grpc-status",
+                                tonic::Status::GRPC_STATUS,
                                 (tonic::Code::Unimplemented as i32).into(),
                             );
                         headers

tonic-reflection/src/generated/grpc_reflection_v1.rs

@@ -425,7 +425,7 @@ pub mod server_reflection_server {
                         let headers = response.headers_mut();
                         headers
                             .insert(
-                                "grpc-status",
+                                tonic::Status::GRPC_STATUS,
                                 (tonic::Code::Unimplemented as i32).into(),
                             );
                         headers

tonic-reflection/src/generated/grpc_reflection_v1alpha.rs

@@ -425,7 +425,7 @@ pub mod server_reflection_server {
                         let headers = response.headers_mut();
                         headers
                             .insert(
-                                "grpc-status",
+                                tonic::Status::GRPC_STATUS,
                                 (tonic::Code::Unimplemented as i32).into(),
                             );
                         headers

tonic-web/src/call.rs

@@ -522,8 +522,11 @@ mod tests {
     #[test]
     fn decode_trailers() {
         let mut headers = HeaderMap::new();
-        headers.insert("grpc-status", 0.into());
-        headers.insert("grpc-message", "this is a message".try_into().unwrap());
+        headers.insert(Status::GRPC_STATUS, 0.into());
+        headers.insert(
+            Status::GRPC_MESSAGE,
+            "this is a message".try_into().unwrap(),
+        );
 
         let trailers = make_trailers_frame(headers.clone());
 
@@ -566,7 +569,7 @@ mod tests {
         let trailers = decode_trailers_frame(Bytes::copy_from_slice(&buf[81..]))
             .unwrap()
             .unwrap();
-        let status = trailers.get("grpc-status").unwrap();
+        let status = trailers.get(Status::GRPC_STATUS).unwrap();
         assert_eq!(status.to_str().unwrap(), "0")
     }
 
@@ -624,8 +627,8 @@ mod tests {
             .unwrap();
 
         let mut expected = HeaderMap::new();
-        expected.insert("grpc-status", "0".parse().unwrap());
-        expected.insert("grpc-message", "".parse().unwrap());
+        expected.insert(Status::GRPC_STATUS, "0".parse().unwrap());
+        expected.insert(Status::GRPC_MESSAGE, "".parse().unwrap());
         expected.insert("a", "1".parse().unwrap());
         expected.insert("b", "2".parse().unwrap());
 

tonic-web/src/lib.rs

@@ -109,14 +109,17 @@ mod service;
 
 use http::header::HeaderName;
 use std::time::Duration;
-use tonic::{body::BoxBody, server::NamedService};
+use tonic::{body::BoxBody, server::NamedService, Status};
 use tower_http::cors::{AllowOrigin, CorsLayer};
 use tower_layer::Layer;
 use tower_service::Service;
 
 const DEFAULT_MAX_AGE: Duration = Duration::from_secs(24 * 60 * 60);
-const DEFAULT_EXPOSED_HEADERS: [&str; 3] =
-    ["grpc-status", "grpc-message", "grpc-status-details-bin"];
+const DEFAULT_EXPOSED_HEADERS: [HeaderName; 3] = [
+    Status::GRPC_STATUS,
+    Status::GRPC_MESSAGE,
+    Status::GRPC_STATUS_DETAILS,
+];
 const DEFAULT_ALLOW_HEADERS: [&str; 4] =
     ["x-grpc-web", "content-type", "x-user-agent", "grpc-timeout"];
 
@@ -136,13 +139,7 @@ where
         .allow_origin(AllowOrigin::mirror_request())
         .allow_credentials(true)
         .max_age(DEFAULT_MAX_AGE)
-        .expose_headers(
-            DEFAULT_EXPOSED_HEADERS
-                .iter()
-                .cloned()
-                .map(HeaderName::from_static)
-                .collect::<Vec<HeaderName>>(),
-        )
+        .expose_headers(DEFAULT_EXPOSED_HEADERS.iter().cloned().collect::<Vec<_>>())
         .allow_headers(
             DEFAULT_ALLOW_HEADERS
                 .iter()

tonic/src/codec/prost.rs

@@ -267,7 +267,7 @@ mod tests {
             frame
                 .into_trailers()
                 .expect("got trailers")
-                .get("grpc-status")
+                .get(Status::GRPC_STATUS)
                 .expect("grpc-status header"),
             "11"
         );
@@ -302,7 +302,7 @@ mod tests {
             frame
                 .into_trailers()
                 .expect("got trailers")
-                .get("grpc-status")
+                .get(Status::GRPC_STATUS)
                 .expect("grpc-status header"),
             "8"
         );

tonic/src/service/router.rs

@@ -2,8 +2,9 @@ use crate::{
     body::{boxed, BoxBody},
     metadata::GRPC_CONTENT_TYPE,
     server::NamedService,
+    Status,
 };
-use http::{HeaderName, HeaderValue, Request, Response};
+use http::{HeaderValue, Request, Response};
 use std::{
     convert::Infallible,
     fmt,
@@ -124,10 +125,7 @@ impl From<axum::Router> for Routes {
 async fn unimplemented() -> impl axum::response::IntoResponse {
     let status = http::StatusCode::OK;
     let headers = [
-        (
-            HeaderName::from_static("grpc-status"),
-            HeaderValue::from_static("12"),
-        ),
+        (Status::GRPC_STATUS, HeaderValue::from_static("12")),
         (http::header::CONTENT_TYPE, GRPC_CONTENT_TYPE),
     ];
     (status, headers)

tonic/src/status.rs

@@ -21,10 +21,6 @@ const ENCODING_SET: &AsciiSet = &CONTROLS
     .add(b'{')
     .add(b'}');
 
-const GRPC_STATUS_HEADER_CODE: HeaderName = HeaderName::from_static("grpc-status");
-const GRPC_STATUS_MESSAGE_HEADER: HeaderName = HeaderName::from_static("grpc-message");
-const GRPC_STATUS_DETAILS_HEADER: HeaderName = HeaderName::from_static("grpc-status-details-bin");
-
 /// A gRPC status describing the result of an RPC call.
 ///
 /// Values can be created using the `new` function or one of the specialized
@@ -442,10 +438,10 @@ impl Status {
 
     /// Extract a `Status` from a hyper `HeaderMap`.
     pub fn from_header_map(header_map: &HeaderMap) -> Option<Status> {
-        header_map.get(GRPC_STATUS_HEADER_CODE).map(|code| {
+        header_map.get(Self::GRPC_STATUS).map(|code| {
             let code = Code::from_bytes(code.as_ref());
             let error_message = header_map
-                .get(GRPC_STATUS_MESSAGE_HEADER)
+                .get(Self::GRPC_MESSAGE)
                 .map(|header| {
                     percent_decode(header.as_bytes())
                         .decode_utf8()
@@ -454,7 +450,7 @@ impl Status {
                 .unwrap_or_else(|| Ok(String::new()));
 
             let details = header_map
-                .get(GRPC_STATUS_DETAILS_HEADER)
+                .get(Self::GRPC_STATUS_DETAILS)
                 .map(|h| {
                     crate::util::base64::STANDARD
                         .decode(h.as_bytes())
@@ -464,9 +460,9 @@ impl Status {
                 .unwrap_or_default();
 
             let mut other_headers = header_map.clone();
-            other_headers.remove(GRPC_STATUS_HEADER_CODE);
-            other_headers.remove(GRPC_STATUS_MESSAGE_HEADER);
-            other_headers.remove(GRPC_STATUS_DETAILS_HEADER);
+            other_headers.remove(Self::GRPC_STATUS);
+            other_headers.remove(Self::GRPC_MESSAGE);
+            other_headers.remove(Self::GRPC_STATUS_DETAILS);
 
             match error_message {
                 Ok(message) => Status {
@@ -525,15 +521,15 @@ impl Status {
     pub fn add_header(&self, header_map: &mut HeaderMap) -> Result<(), Self> {
         header_map.extend(self.metadata.clone().into_sanitized_headers());
 
-        header_map.insert(GRPC_STATUS_HEADER_CODE, self.code.to_header_value());
+        header_map.insert(Self::GRPC_STATUS, self.code.to_header_value());
 
         if !self.message.is_empty() {
             let to_write = Bytes::copy_from_slice(
                 Cow::from(percent_encode(self.message().as_bytes(), ENCODING_SET)).as_bytes(),
             );
 
             header_map.insert(
-                GRPC_STATUS_MESSAGE_HEADER,
+                Self::GRPC_MESSAGE,
                 HeaderValue::from_maybe_shared(to_write).map_err(invalid_header_value_byte)?,
             );
         }
@@ -542,7 +538,7 @@ impl Status {
             let details = crate::util::base64::STANDARD_NO_PAD.encode(&self.details[..]);
 
             header_map.insert(
-                GRPC_STATUS_DETAILS_HEADER,
+                Self::GRPC_STATUS_DETAILS,
                 HeaderValue::from_maybe_shared(details).map_err(invalid_header_value_byte)?,
             );
         }
@@ -591,6 +587,13 @@ impl Status {
         self.add_header(response.headers_mut()).unwrap();
         response
     }
+
+    #[doc(hidden)]
+    pub const GRPC_STATUS: HeaderName = HeaderName::from_static("grpc-status");
+    #[doc(hidden)]
+    pub const GRPC_MESSAGE: HeaderName = HeaderName::from_static("grpc-message");
+    #[doc(hidden)]
+    pub const GRPC_STATUS_DETAILS: HeaderName = HeaderName::from_static("grpc-status-details-bin");
 }
 
 fn find_status_in_source_chain(err: &(dyn Error + 'static)) -> Option<Status> {
@@ -1005,7 +1008,7 @@ mod tests {
 
         let b64_details = crate::util::base64::STANDARD_NO_PAD.encode(DETAILS);
 
-        assert_eq!(header_map[super::GRPC_STATUS_DETAILS_HEADER], b64_details);
+        assert_eq!(header_map[Status::GRPC_STATUS_DETAILS], b64_details);
 
         let status = Status::from_header_map(&header_map).unwrap();