From 66eee6152a690e5b6afa693600954c3e1f2d9b5f Mon Sep 17 00:00:00 2001
From: Fangdun Tsai <fundon@pindash.io>
Date: Sun, 17 Dec 2023 03:33:16 +0800
Subject: [PATCH] feat(core): improve handlers and add ServiceHandler (#117)

---
 viz-core/src/handler.rs                   | 36 ++++++++++++-----
 viz-core/src/handler/after.rs             |  3 +-
 viz-core/src/handler/and_then.rs          |  3 +-
 viz-core/src/handler/around.rs            |  3 +-
 viz-core/src/handler/before.rs            |  3 +-
 viz-core/src/handler/catch_error.rs       |  3 +-
 viz-core/src/handler/catch_unwind.rs      |  5 ++-
 viz-core/src/handler/either.rs            |  7 ++--
 viz-core/src/handler/fn_ext_hanlder.rs    |  4 +-
 viz-core/src/handler/into_handler.rs      |  4 +-
 viz-core/src/handler/map.rs               |  3 +-
 viz-core/src/handler/map_err.rs           |  3 +-
 viz-core/src/handler/map_into_response.rs |  4 +-
 viz-core/src/handler/or_else.rs           |  3 +-
 viz-core/src/handler/service.rs           | 48 +++++++++++++++++++++++
 15 files changed, 104 insertions(+), 28 deletions(-)
 create mode 100644 viz-core/src/handler/service.rs

diff --git a/viz-core/src/handler.rs b/viz-core/src/handler.rs
index efe5337a..a312d4d9 100644
--- a/viz-core/src/handler.rs
+++ b/viz-core/src/handler.rs
@@ -50,6 +50,9 @@ pub use or_else::OrElse;
 mod transform;
 pub use transform::Transform;
 
+mod service;
+pub use service::ServiceHandler;
+
 /// A simplified asynchronous interface for handling input and output.
 ///
 /// Composable request handlers.
@@ -83,14 +86,6 @@ where
 /// [`FutureExt`]: https://docs.rs/futures/latest/futures/future/trait.FutureExt.html
 /// [`StreamExt`]: https://docs.rs/futures/latest/futures/stream/trait.StreamExt.html
 pub trait HandlerExt<I>: Handler<I> {
-    /// Converts this Handler into a [`BoxHandler`].
-    fn boxed(self) -> BoxHandler<I, Self::Output>
-    where
-        Self: Sized,
-    {
-        Box::new(self)
-    }
-
     /// Maps the input before the handler calls.
     fn before<F>(self, f: F) -> Before<Self, F>
     where
@@ -115,6 +110,21 @@ pub trait HandlerExt<I>: Handler<I> {
         Around::new(self, f)
     }
 
+    /// Wraps this handler in an Either handler, making it the left-hand variant of that Either.
+    ///
+    /// Returns the left-hand variant if `enable` is true, otherwise returns the right-hand
+    /// variant.
+    fn either<R>(self, r: R, enable: bool) -> Either<Self, R>
+    where
+        Self: Sized,
+    {
+        if enable {
+            Either::Left(self)
+        } else {
+            Either::Right(r)
+        }
+    }
+
     /// Maps the `Ok` value of the output if after the handler called.
     fn map<F>(self, f: F) -> Map<Self, F>
     where
@@ -173,7 +183,15 @@ pub trait HandlerExt<I>: Handler<I> {
         CatchUnwind::new(self, f)
     }
 
-    /// Returns a new [Handler] that wrapping the `Self` and a type implementing [`Transform`].
+    /// Converts this Handler into a [`BoxHandler`].
+    fn boxed(self) -> BoxHandler<I, Self::Output>
+    where
+        Self: Sized,
+    {
+        Box::new(self)
+    }
+
+    /// Returns a new [`Handler`] that wrapping the `Self` and a type implementing [`Transform`].
     fn with<T>(self, t: T) -> T::Output
     where
         T: Transform<Self>,
diff --git a/viz-core/src/handler/after.rs b/viz-core/src/handler/after.rs
index b478a56e..0ff25ba1 100644
--- a/viz-core/src/handler/after.rs
+++ b/viz-core/src/handler/after.rs
@@ -8,8 +8,9 @@ pub struct After<H, F> {
 }
 
 impl<H, F> After<H, F> {
+    /// Creates an [`After`] handler.
     #[inline]
-    pub(super) fn new(h: H, f: F) -> Self {
+    pub fn new(h: H, f: F) -> Self {
         Self { h, f }
     }
 }
diff --git a/viz-core/src/handler/and_then.rs b/viz-core/src/handler/and_then.rs
index 579497d5..aa32dc24 100644
--- a/viz-core/src/handler/and_then.rs
+++ b/viz-core/src/handler/and_then.rs
@@ -8,8 +8,9 @@ pub struct AndThen<H, F> {
 }
 
 impl<H, F> AndThen<H, F> {
+    /// Creates an [`AndThen`] handler.
     #[inline]
-    pub(super) fn new(h: H, f: F) -> Self {
+    pub fn new(h: H, f: F) -> Self {
         Self { h, f }
     }
 }
diff --git a/viz-core/src/handler/around.rs b/viz-core/src/handler/around.rs
index 455ccb17..342efafe 100644
--- a/viz-core/src/handler/around.rs
+++ b/viz-core/src/handler/around.rs
@@ -11,8 +11,9 @@ pub struct Around<H, F> {
 }
 
 impl<H, F> Around<H, F> {
+    /// Creates an [`Around`] handler.
     #[inline]
-    pub(super) fn new(h: H, f: F) -> Self {
+    pub fn new(h: H, f: F) -> Self {
         Self { h, f }
     }
 }
diff --git a/viz-core/src/handler/before.rs b/viz-core/src/handler/before.rs
index 11d495a7..309fa7ec 100644
--- a/viz-core/src/handler/before.rs
+++ b/viz-core/src/handler/before.rs
@@ -8,8 +8,9 @@ pub struct Before<H, F> {
 }
 
 impl<H, F> Before<H, F> {
+    /// Creates a [`Before`] handler.
     #[inline]
-    pub(super) fn new(h: H, f: F) -> Self {
+    pub fn new(h: H, f: F) -> Self {
         Self { h, f }
     }
 }
diff --git a/viz-core/src/handler/catch_error.rs b/viz-core/src/handler/catch_error.rs
index 0ad10a6c..692f31ce 100644
--- a/viz-core/src/handler/catch_error.rs
+++ b/viz-core/src/handler/catch_error.rs
@@ -25,8 +25,9 @@ where
 }
 
 impl<H, F, R, E> CatchError<H, F, R, E> {
+    /// Creates a [`CatchError`] handler.
     #[inline]
-    pub(super) fn new(h: H, f: F) -> Self {
+    pub fn new(h: H, f: F) -> Self {
         Self {
             h,
             f,
diff --git a/viz-core/src/handler/catch_unwind.rs b/viz-core/src/handler/catch_unwind.rs
index 7dcc9cb8..81fe847d 100644
--- a/viz-core/src/handler/catch_unwind.rs
+++ b/viz-core/src/handler/catch_unwind.rs
@@ -12,8 +12,9 @@ pub struct CatchUnwind<H, F> {
 }
 
 impl<H, F> CatchUnwind<H, F> {
+    /// Creates an [`CatchUnwind`] handler.
     #[inline]
-    pub(super) fn new(h: H, f: F) -> Self {
+    pub fn new(h: H, f: F) -> Self {
         Self { h, f }
     }
 }
@@ -22,8 +23,8 @@ impl<H, F> CatchUnwind<H, F> {
 impl<H, F, I, O, R> Handler<I> for CatchUnwind<H, F>
 where
     I: Send + 'static,
-    O: IntoResponse + Send,
     H: Handler<I, Output = Result<O>> + Clone,
+    O: IntoResponse + Send,
     F: Handler<Box<dyn Any + Send>, Output = R> + Clone,
     R: IntoResponse,
 {
diff --git a/viz-core/src/handler/either.rs b/viz-core/src/handler/either.rs
index 0fecc3e9..5a3ad828 100644
--- a/viz-core/src/handler/either.rs
+++ b/viz-core/src/handler/either.rs
@@ -19,9 +19,10 @@ where
     type Output = O;
 
     async fn call(&self, i: I) -> Self::Output {
-        match self {
-            Self::Left(l) => l.call(i).await,
-            Self::Right(r) => r.call(i).await,
+        match &self {
+            Self::Left(l) => l.call(i),
+            Self::Right(r) => r.call(i),
         }
+        .await
     }
 }
diff --git a/viz-core/src/handler/fn_ext_hanlder.rs b/viz-core/src/handler/fn_ext_hanlder.rs
index 99fd3026..665f9bb9 100644
--- a/viz-core/src/handler/fn_ext_hanlder.rs
+++ b/viz-core/src/handler/fn_ext_hanlder.rs
@@ -16,8 +16,8 @@ where
 }
 
 impl<H, E, O> FnExtHandler<H, E, O> {
-    /// Create a new `Handler` for the extractors.
-    pub(super) fn new(h: H) -> Self {
+    /// Creates a new `Handler` for the extractors.
+    pub fn new(h: H) -> Self {
         Self(h, PhantomData)
     }
 }
diff --git a/viz-core/src/handler/into_handler.rs b/viz-core/src/handler/into_handler.rs
index c62bd8b0..5ca17b8d 100644
--- a/viz-core/src/handler/into_handler.rs
+++ b/viz-core/src/handler/into_handler.rs
@@ -2,12 +2,12 @@ use crate::{FromRequest, IntoResponse, Request, Result};
 
 use super::{FnExt, FnExtHandler, Handler};
 
-/// Trait implemented by types that can be converted to a [`Handler`].
+/// The trait implemented by types that can be converted to a [`Handler`].
 pub trait IntoHandler<E, I> {
     /// The target handler.
     type Handler: Handler<I>;
 
-    /// Convert self to a [Handler].
+    /// Converts self to a [`Handler`].
     #[must_use]
     fn into_handler(self) -> Self::Handler;
 }
diff --git a/viz-core/src/handler/map.rs b/viz-core/src/handler/map.rs
index 9f7c9dd6..2a5a0503 100644
--- a/viz-core/src/handler/map.rs
+++ b/viz-core/src/handler/map.rs
@@ -8,8 +8,9 @@ pub struct Map<H, F> {
 }
 
 impl<H, F> Map<H, F> {
+    /// Creates a [`Map`] handler.
     #[inline]
-    pub(super) fn new(h: H, f: F) -> Self {
+    pub fn new(h: H, f: F) -> Self {
         Self { h, f }
     }
 }
diff --git a/viz-core/src/handler/map_err.rs b/viz-core/src/handler/map_err.rs
index 22fe4a19..54bdcdd4 100644
--- a/viz-core/src/handler/map_err.rs
+++ b/viz-core/src/handler/map_err.rs
@@ -8,8 +8,9 @@ pub struct MapErr<H, F> {
 }
 
 impl<H, F> MapErr<H, F> {
+    /// Creates a [`MapErr`] handler.
     #[inline]
-    pub(super) fn new(h: H, f: F) -> Self {
+    pub fn new(h: H, f: F) -> Self {
         Self { h, f }
     }
 }
diff --git a/viz-core/src/handler/map_into_response.rs b/viz-core/src/handler/map_into_response.rs
index c923f3d5..4718990d 100644
--- a/viz-core/src/handler/map_into_response.rs
+++ b/viz-core/src/handler/map_into_response.rs
@@ -5,9 +5,9 @@ use crate::{async_trait, Handler, IntoResponse, Response, Result};
 pub struct MapInToResponse<H>(pub(crate) H);
 
 impl<H> MapInToResponse<H> {
-    /// Creates a new `Responder`.
+    /// Creates a [`MapInToResponse`] handler.
     #[inline]
-    pub(super) fn new(h: H) -> Self {
+    pub fn new(h: H) -> Self {
         Self(h)
     }
 }
diff --git a/viz-core/src/handler/or_else.rs b/viz-core/src/handler/or_else.rs
index 752128b6..5b8c71b4 100644
--- a/viz-core/src/handler/or_else.rs
+++ b/viz-core/src/handler/or_else.rs
@@ -8,8 +8,9 @@ pub struct OrElse<H, F> {
 }
 
 impl<H, F> OrElse<H, F> {
+    /// Creates an [`OrElse`] handler.
     #[inline]
-    pub(super) fn new(h: H, f: F) -> Self {
+    pub fn new(h: H, f: F) -> Self {
         Self { h, f }
     }
 }
diff --git a/viz-core/src/handler/service.rs b/viz-core/src/handler/service.rs
new file mode 100644
index 00000000..af53e054
--- /dev/null
+++ b/viz-core/src/handler/service.rs
@@ -0,0 +1,48 @@
+use http_body_util::BodyExt;
+use hyper::service::Service;
+
+use crate::{async_trait, Body, Bytes, Error, Handler, Request, Response, Result};
+
+/// Converts a hyper [`Service`] to a viz [`Handler`].
+#[derive(Debug, Clone)]
+pub struct ServiceHandler<S> {
+    s: S,
+}
+
+impl<S> ServiceHandler<S> {
+    /// Creates a new [`ServiceHandler`].
+    pub fn new(s: S) -> Self {
+        Self { s }
+    }
+}
+
+#[async_trait]
+impl<I, O, S> Handler<Request<I>> for ServiceHandler<S>
+where
+    I: Body + Send + Unpin + 'static,
+    // O: Body + Send + 'static,
+    O: Body + Send + Sync + 'static,
+    O::Data: Into<Bytes>,
+    O::Error: Into<Error>,
+    S: Service<Request<I>, Response = Response<O>> + Send + Sync + Clone + 'static,
+    S::Future: Send,
+    S::Error: Into<Error>,
+{
+    type Output = Result<Response>;
+
+    async fn call(&self, req: Request<I>) -> Self::Output {
+        self.s
+            .call(req)
+            .await
+            .map(|resp| {
+                resp.map(|body| {
+                    body.map_frame(|f| f.map_data(Into::into))
+                        .map_err(Into::into)
+                        // .boxed_unsync()
+                        .boxed()
+                })
+                .map(Into::into)
+            })
+            .map_err(Into::into)
+    }
+}