From 40536dc13428f6338610d74f7b45a5f9c87d9335 Mon Sep 17 00:00:00 2001
From: Francesco Guardiani <francescoguard@gmail.com>
Date: Fri, 28 Oct 2022 19:59:01 +0200
Subject: [PATCH] feat(web): Implement tower::Layer for tonic_web::Config
 (#1119)

Signed-off-by: slinkydeveloper <francescoguard@gmail.com>
---
 tonic-web/Cargo.toml     |  1 +
 tonic-web/src/config.rs  |  4 +---
 tonic-web/src/layer.rs   | 31 +++++++++++++++++++++++++++++++
 tonic-web/src/lib.rs     |  7 ++++---
 tonic-web/src/service.rs | 10 ++++++++++
 5 files changed, 47 insertions(+), 6 deletions(-)
 create mode 100644 tonic-web/src/layer.rs

diff --git a/tonic-web/Cargo.toml b/tonic-web/Cargo.toml
index fed2817f2..d8e4b7bb6 100644
--- a/tonic-web/Cargo.toml
+++ b/tonic-web/Cargo.toml
@@ -24,6 +24,7 @@ hyper = "0.14"
 pin-project = "1"
 tonic = {version = "0.8", path = "../tonic", default-features = false, features = ["transport"]}
 tower-service = "0.3"
+tower-layer = "0.3"
 tracing = "0.1"
 
 [dev-dependencies]
diff --git a/tonic-web/src/config.rs b/tonic-web/src/config.rs
index e27698f2e..5c965a18a 100644
--- a/tonic-web/src/config.rs
+++ b/tonic-web/src/config.rs
@@ -4,7 +4,6 @@ use std::time::Duration;
 
 use http::{header::HeaderName, HeaderValue};
 use tonic::body::BoxBody;
-use tonic::transport::NamedService;
 use tower_service::Service;
 
 use crate::service::GrpcWeb;
@@ -152,11 +151,10 @@ impl Config {
     pub fn enable<S>(&self, service: S) -> GrpcWeb<S>
     where
         S: Service<http::Request<hyper::Body>, Response = http::Response<BoxBody>>,
-        S: NamedService + Clone + Send + 'static,
+        S: Clone + Send + 'static,
         S::Future: Send + 'static,
         S::Error: Into<BoxError> + Send,
     {
-        tracing::trace!("enabled for {}", S::NAME);
         GrpcWeb::new(service, self.clone())
     }
 }
diff --git a/tonic-web/src/layer.rs b/tonic-web/src/layer.rs
new file mode 100644
index 000000000..95ca2ef66
--- /dev/null
+++ b/tonic-web/src/layer.rs
@@ -0,0 +1,31 @@
+use super::{BoxBody, BoxError, Config, GrpcWeb};
+
+use tower_layer::Layer;
+use tower_service::Service;
+
+/// Layer implementing the grpc-web protocol.
+#[derive(Debug, Clone)]
+pub struct GrpcWebLayer {
+    _priv: (),
+}
+
+impl GrpcWebLayer {
+    /// Create a new grpc-web layer.
+    pub fn new() -> GrpcWebLayer {
+        Self { _priv: () }
+    }
+}
+
+impl<S> Layer<S> for GrpcWebLayer
+where
+    S: Service<http::Request<hyper::Body>, Response = http::Response<BoxBody>>,
+    S: Clone + Send + 'static,
+    S::Future: Send + 'static,
+    S::Error: Into<BoxError> + Send,
+{
+    type Service = GrpcWeb<S>;
+
+    fn layer(&self, inner: S) -> Self::Service {
+        Config::default().enable(inner)
+    }
+}
diff --git a/tonic-web/src/lib.rs b/tonic-web/src/lib.rs
index eb46b3d04..ad8799d2c 100644
--- a/tonic-web/src/lib.rs
+++ b/tonic-web/src/lib.rs
@@ -88,17 +88,18 @@
 #![doc(issue_tracker_base_url = "https://github.com/hyperium/tonic/issues/")]
 
 pub use config::Config;
+pub use layer::GrpcWebLayer;
+pub use service::GrpcWeb;
 
 mod call;
 mod config;
 mod cors;
+mod layer;
 mod service;
 
-use crate::service::GrpcWeb;
 use std::future::Future;
 use std::pin::Pin;
 use tonic::body::BoxBody;
-use tonic::transport::NamedService;
 use tower_service::Service;
 
 /// enable a tonic service to handle grpc-web requests with the default configuration.
@@ -107,7 +108,7 @@ use tower_service::Service;
 pub fn enable<S>(service: S) -> GrpcWeb<S>
 where
     S: Service<http::Request<hyper::Body>, Response = http::Response<BoxBody>>,
-    S: NamedService + Clone + Send + 'static,
+    S: Clone + Send + 'static,
     S::Future: Send + 'static,
     S::Error: Into<BoxError> + Send,
 {
diff --git a/tonic-web/src/service.rs b/tonic-web/src/service.rs
index 03f31b221..c4beac1a0 100644
--- a/tonic-web/src/service.rs
+++ b/tonic-web/src/service.rs
@@ -15,6 +15,7 @@ use crate::{BoxError, BoxFuture, Config};
 
 const GRPC: &str = "application/grpc";
 
+/// Service implementing the grpc-web protocol.
 #[derive(Debug, Clone)]
 pub struct GrpcWeb<S> {
     inner: S,
@@ -266,6 +267,7 @@ mod tests {
     mod grpc_web {
         use super::*;
         use http::HeaderValue;
+        use tower_layer::Layer;
 
         fn request() -> Request<Body> {
             Request::builder()
@@ -284,6 +286,14 @@ mod tests {
             assert_eq!(res.status(), StatusCode::OK);
         }
 
+        #[tokio::test]
+        async fn web_layer() {
+            let mut svc = crate::GrpcWebLayer::new().layer(Svc);
+            let res = svc.call(request()).await.unwrap();
+
+            assert_eq!(res.status(), StatusCode::OK);
+        }
+
         #[tokio::test]
         async fn without_origin() {
             let mut svc = crate::enable(Svc);