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Author: s0l0ist

lambda-http/src/streaming.rs

@@ -172,3 +172,56 @@ where
         }
     }
 }
+
+#[cfg(test)]
+mod test_stream_adapter {
+    use super::*;
+
+    use crate::Body;
+    use http::StatusCode;
+
+    // A middleware that logs requests before forwarding them to another service
+    struct LogService<S> {
+        inner: S,
+    }
+
+    impl<S> Service<LambdaEvent<LambdaRequest>> for LogService<S>
+    where
+        S: Service<LambdaEvent<LambdaRequest>>,
+    {
+        type Response = S::Response;
+        type Error = S::Error;
+        type Future = S::Future;
+
+        fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+            self.inner.poll_ready(cx)
+        }
+
+        fn call(&mut self, event: LambdaEvent<LambdaRequest>) -> Self::Future {
+            // Log the request
+            println!("Lambda event: {event:#?}");
+
+            self.inner.call(event)
+        }
+    }
+
+    /// This tests that `StreamAdapter` can be used in a `tower::Service` where
+    /// the user may require additional middleware between `lambda_runtime::run`
+    /// and where the `LambdaEvent` is converted into a `Request`.
+    #[test]
+    fn stream_adapter_is_boxable() {
+        let _svc = ServiceBuilder::new()
+            .layer_fn(|service| {
+                // This could be any middleware that logs, inspects, or
+                // manipulates the `LambdaEvent` before it's converted to a
+                // `Request` by `Adapter`.
+
+                LogService { inner: service }
+            })
+            .layer_fn(StreamAdapter::from)
+            .service_fn(
+                |_req: Request| async move { http::Response::builder().status(StatusCode::OK).body(Body::Empty) },
+            )
+            .boxed();
+    }
+}