From 71ba4d28a3293c37db1e9d8974b6eab020006406 Mon Sep 17 00:00:00 2001
From: Nikolay Kim <fafhrd91@gmail.com>
Date: Wed, 15 Jan 2025 15:59:26 +0500
Subject: [PATCH] Add EitherService/EitherServiceFactory (#500)

---
 ntex-util/CHANGES.md             |   4 +
 ntex-util/Cargo.toml             |   2 +-
 ntex-util/src/services/either.rs | 239 +++++++++++++++++++++++++++++++
 ntex-util/src/services/mod.rs    |   1 +
 4 files changed, 245 insertions(+), 1 deletion(-)
 create mode 100644 ntex-util/src/services/either.rs

diff --git a/ntex-util/CHANGES.md b/ntex-util/CHANGES.md
index 3cad994d..7388ee15 100644
--- a/ntex-util/CHANGES.md
+++ b/ntex-util/CHANGES.md
@@ -1,5 +1,9 @@
 # Changes
 
+## [2.9.0] - 2025-01-15
+
+* Add EitherService/EitherServiceFactory
+
 ## [2.8.0] - 2024-12-04
 
 * Use updated Service trait
diff --git a/ntex-util/Cargo.toml b/ntex-util/Cargo.toml
index b43366f3..96ceff5f 100644
--- a/ntex-util/Cargo.toml
+++ b/ntex-util/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "ntex-util"
-version = "2.8.0"
+version = "2.9.0"
 authors = ["ntex contributors <team@ntex.rs>"]
 description = "Utilities for ntex framework"
 keywords = ["network", "framework", "async", "futures"]
diff --git a/ntex-util/src/services/either.rs b/ntex-util/src/services/either.rs
new file mode 100644
index 00000000..a17d7672
--- /dev/null
+++ b/ntex-util/src/services/either.rs
@@ -0,0 +1,239 @@
+//! Either service allows to use different services for handling request
+use std::{fmt, task::Context};
+
+use ntex_service::{Service, ServiceCtx, ServiceFactory};
+
+use crate::future::Either;
+
+#[derive(Clone)]
+/// Either service
+///
+/// Either service allows to use different services for handling requests
+pub struct EitherService<SLeft, SRight> {
+    svc: Either<SLeft, SRight>,
+}
+
+#[derive(Clone)]
+/// Either service factory
+///
+/// Either service allows to use different services for handling requests
+pub struct EitherServiceFactory<ChooseFn, SFLeft, SFRight> {
+    left: SFLeft,
+    right: SFRight,
+    choose_left_fn: ChooseFn,
+}
+
+impl<ChooseFn, SFLeft, SFRight> EitherServiceFactory<ChooseFn, SFLeft, SFRight> {
+    /// Create `Either` service factory
+    pub fn new(choose_left_fn: ChooseFn, sf_left: SFLeft, sf_right: SFRight) -> Self {
+        EitherServiceFactory {
+            choose_left_fn,
+            left: sf_left,
+            right: sf_right,
+        }
+    }
+}
+
+impl<ChooseFn, SFLeft, SFRight> fmt::Debug
+    for EitherServiceFactory<ChooseFn, SFLeft, SFRight>
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("EitherServiceFactory")
+            .field("left", &std::any::type_name::<SFLeft>())
+            .field("right", &std::any::type_name::<SFRight>())
+            .field("choose_fn", &std::any::type_name::<ChooseFn>())
+            .finish()
+    }
+}
+
+impl<R, C, ChooseFn, SFLeft, SFRight> ServiceFactory<R, C>
+    for EitherServiceFactory<ChooseFn, SFLeft, SFRight>
+where
+    ChooseFn: Fn(&C) -> bool,
+    SFLeft: ServiceFactory<R, C>,
+    SFRight: ServiceFactory<
+        R,
+        C,
+        Response = SFLeft::Response,
+        InitError = SFLeft::InitError,
+        Error = SFLeft::Error,
+    >,
+{
+    type Response = SFLeft::Response;
+    type Error = SFLeft::Error;
+    type InitError = SFLeft::InitError;
+    type Service = EitherService<SFLeft::Service, SFRight::Service>;
+
+    async fn create(&self, cfg: C) -> Result<Self::Service, Self::InitError> {
+        let choose_left = (self.choose_left_fn)(&cfg);
+
+        if choose_left {
+            let svc = self.left.create(cfg).await?;
+            Ok(EitherService {
+                svc: Either::Left(svc),
+            })
+        } else {
+            let svc = self.right.create(cfg).await?;
+            Ok(EitherService {
+                svc: Either::Right(svc),
+            })
+        }
+    }
+}
+
+impl<SLeft, SRight> EitherService<SLeft, SRight> {
+    /// Create `Either` service
+    pub fn left(svc: SLeft) -> Self {
+        EitherService {
+            svc: Either::Left(svc),
+        }
+    }
+
+    /// Create `Either` service
+    pub fn right(svc: SRight) -> Self {
+        EitherService {
+            svc: Either::Right(svc),
+        }
+    }
+}
+
+impl<SLeft, SRight> fmt::Debug for EitherService<SLeft, SRight> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("EitherService")
+            .field("left", &std::any::type_name::<SLeft>())
+            .field("right", &std::any::type_name::<SRight>())
+            .finish()
+    }
+}
+
+impl<Req, SLeft, SRight> Service<Req> for EitherService<SLeft, SRight>
+where
+    SLeft: Service<Req>,
+    SRight: Service<Req, Response = SLeft::Response, Error = SLeft::Error>,
+{
+    type Response = SLeft::Response;
+    type Error = SLeft::Error;
+
+    #[inline]
+    async fn ready(&self, ctx: ServiceCtx<'_, Self>) -> Result<(), Self::Error> {
+        match self.svc {
+            Either::Left(ref svc) => ctx.ready(svc).await,
+            Either::Right(ref svc) => ctx.ready(svc).await,
+        }
+    }
+
+    #[inline]
+    async fn shutdown(&self) {
+        match self.svc {
+            Either::Left(ref svc) => svc.shutdown().await,
+            Either::Right(ref svc) => svc.shutdown().await,
+        }
+    }
+
+    #[inline]
+    async fn call(
+        &self,
+        req: Req,
+        ctx: ServiceCtx<'_, Self>,
+    ) -> Result<Self::Response, Self::Error> {
+        match self.svc {
+            Either::Left(ref svc) => ctx.call(svc, req).await,
+            Either::Right(ref svc) => ctx.call(svc, req).await,
+        }
+    }
+
+    #[inline]
+    fn poll(&self, cx: &mut Context<'_>) -> Result<(), Self::Error> {
+        match self.svc {
+            Either::Left(ref svc) => svc.poll(cx),
+            Either::Right(ref svc) => svc.poll(cx),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use ntex_service::{Pipeline, ServiceFactory};
+
+    use super::*;
+
+    #[derive(Copy, Clone, Debug, PartialEq)]
+    struct Svc1;
+    impl Service<()> for Svc1 {
+        type Response = &'static str;
+        type Error = ();
+
+        async fn call(&self, _: (), _: ServiceCtx<'_, Self>) -> Result<&'static str, ()> {
+            Ok("svc1")
+        }
+    }
+
+    #[derive(Clone)]
+    struct Svc1Factory;
+    impl ServiceFactory<(), &'static str> for Svc1Factory {
+        type Response = &'static str;
+        type Error = ();
+        type InitError = ();
+        type Service = Svc1;
+
+        async fn create(&self, _: &'static str) -> Result<Self::Service, Self::InitError> {
+            Ok(Svc1)
+        }
+    }
+
+    #[derive(Copy, Clone, Debug, PartialEq)]
+    struct Svc2;
+    impl Service<()> for Svc2 {
+        type Response = &'static str;
+        type Error = ();
+
+        async fn call(&self, _: (), _: ServiceCtx<'_, Self>) -> Result<&'static str, ()> {
+            Ok("svc2")
+        }
+    }
+
+    #[derive(Clone)]
+    struct Svc2Factory;
+    impl ServiceFactory<(), &'static str> for Svc2Factory {
+        type Response = &'static str;
+        type Error = ();
+        type InitError = ();
+        type Service = Svc2;
+
+        async fn create(&self, _: &'static str) -> Result<Self::Service, Self::InitError> {
+            Ok(Svc2)
+        }
+    }
+
+    type Either = EitherService<Svc1, Svc2>;
+    type EitherFactory<F> = EitherServiceFactory<F, Svc1Factory, Svc2Factory>;
+
+    #[ntex_macros::rt_test2]
+    async fn test_success() {
+        let svc = Pipeline::new(Either::left(Svc1).clone());
+        assert_eq!(svc.call(()).await, Ok("svc1"));
+        assert_eq!(svc.ready().await, Ok(()));
+        svc.shutdown().await;
+
+        let svc = Pipeline::new(Either::right(Svc2).clone());
+        assert_eq!(svc.call(()).await, Ok("svc2"));
+        assert_eq!(svc.ready().await, Ok(()));
+        svc.shutdown().await;
+
+        assert!(format!("{:?}", svc).contains("EitherService"));
+    }
+
+    #[ntex_macros::rt_test2]
+    async fn test_factory() {
+        let factory =
+            EitherFactory::new(|s: &&'static str| *s == "svc1", Svc1Factory, Svc2Factory)
+                .clone();
+        assert!(format!("{:?}", factory).contains("EitherServiceFactory"));
+
+        let svc = factory.pipeline("svc1").await.unwrap();
+        assert_eq!(svc.call(()).await, Ok("svc1"));
+
+        let svc = factory.pipeline("other").await.unwrap();
+        assert_eq!(svc.call(()).await, Ok("svc2"));
+    }
+}
diff --git a/ntex-util/src/services/mod.rs b/ntex-util/src/services/mod.rs
index 6f60afb0..e3942d72 100644
--- a/ntex-util/src/services/mod.rs
+++ b/ntex-util/src/services/mod.rs
@@ -1,4 +1,5 @@
 pub mod buffer;
+pub mod either;
 mod extensions;
 pub mod inflight;
 pub mod keepalive;