chore: generalize type of body

relay-lib/src/hyper_body.rs

@@ -5,19 +5,22 @@ use hyper::body::{Bytes, Incoming};
 
 /// Type for synthetic boxed body
 pub(crate) type BoxBody = combinators::BoxBody<Bytes, hyper::Error>;
-/// Type for either passthrough body or synthetic body
-pub(crate) type EitherBody = Either<Incoming, BoxBody>;
+/// Type for either passthrough body or given body type, specifically synthetic boxed body
+pub(crate) type IncomingOr<B> = Either<Incoming, B>;
 
 /// helper function to build http response with passthrough body
-pub(crate) fn passthrough_response(response: Response<Incoming>) -> Result<Response<EitherBody>> {
-  Ok(response.map(EitherBody::Left))
+pub(crate) fn passthrough_response<B>(response: Response<Incoming>) -> Result<Response<IncomingOr<B>>>
+where
+  B: hyper::body::Body,
+{
+  Ok(response.map(IncomingOr::Left))
 }
 
 /// build http response with status code of 4xx and 5xx
-pub(crate) fn synthetic_error_response(status_code: StatusCode) -> Result<Response<EitherBody>> {
+pub(crate) fn synthetic_response(status_code: StatusCode) -> Result<Response<IncomingOr<BoxBody>>> {
   let res = Response::builder()
     .status(status_code)
-    .body(EitherBody::Right(BoxBody::new(empty())))
+    .body(IncomingOr::Right(BoxBody::new(empty())))
     .unwrap();
   Ok(res)
 }

relay-lib/src/relay/relay_main.rs

@@ -2,7 +2,7 @@ use super::{count::RequestCount, forwarder::InnerForwarder, socket::bind_tcp_soc
 use crate::{
   error::*,
   globals::Globals,
-  hyper_body::{passthrough_response, synthetic_error_response, EitherBody},
+  hyper_body::{passthrough_response, synthetic_response, BoxBody, IncomingOr},
   hyper_executor::LocalExecutor,
   log::*,
   validator::Validator,
@@ -47,7 +47,7 @@ pub async fn serve_request_with_validation<C>(
   // forwarder: Arc<InnerForwarder<C, B>>,
   forwarder: Arc<InnerForwarder<C>>,
   validator: Option<Arc<Validator<C>>>,
-) -> Result<hyper::Response<EitherBody>>
+) -> Result<hyper::Response<IncomingOr<BoxBody>>>
 where
   C: Send + Sync + Connect + Clone + 'static,
 {
@@ -62,7 +62,7 @@ where
       }
       Err(e) => {
         warn!("token validation failed: {}", e);
-        return synthetic_error_response(StatusCode::from(e));
+        return synthetic_response(StatusCode::from(e));
       }
     };
     debug!(
@@ -75,7 +75,7 @@ where
   // serve query as relay
   let res = match forwarder.serve(req, peer_addr, validation_passed).await {
     Ok(res) => passthrough_response(res),
-    Err(e) => synthetic_error_response(StatusCode::from(e)),
+    Err(e) => synthetic_response(StatusCode::from(e)),
   };
   debug!("serve query finish");
   res