diff --git a/src/either.rs b/src/either.rs
new file mode 100644
index 00000000..efc6b3d5
--- /dev/null
+++ b/src/either.rs
@@ -0,0 +1,103 @@
+//! Contains `Either` service and related types and functions.
+use futures::{future, Async, Future, Poll};
+
+use super::service::{NewService, Service};
+
+/// Combine two different service types into a single type.
+///
+/// Both services must be of the same request, response, and error types.
+/// `EitherService` is useful for handling conditional branching in service
+/// middleware to different inner service types.
+pub enum EitherService<A, B> {
+    A(A),
+    B(B),
+}
+
+impl<A, B> Service for EitherService<A, B>
+where
+    A: Service,
+    B: Service<Request = A::Request, Response = A::Response, Error = A::Error>,
+{
+    type Request = A::Request;
+    type Response = A::Response;
+    type Error = A::Error;
+    type Future = future::Either<A::Future, B::Future>;
+
+    fn poll_ready(&mut self) -> Poll<(), Self::Error> {
+        match self {
+            EitherService::A(ref mut inner) => inner.poll_ready(),
+            EitherService::B(ref mut inner) => inner.poll_ready(),
+        }
+    }
+
+    fn call(&mut self, req: Self::Request) -> Self::Future {
+        match self {
+            EitherService::A(ref mut inner) => future::Either::A(inner.call(req)),
+            EitherService::B(ref mut inner) => future::Either::B(inner.call(req)),
+        }
+    }
+}
+
+/// Combine two different new service types into a single type.
+pub enum Either<A, B> {
+    A(A),
+    B(B),
+}
+
+impl<A, B> NewService for Either<A, B>
+where
+    A: NewService,
+    B: NewService<
+        Request = A::Request,
+        Response = A::Response,
+        Error = A::Error,
+        InitError = A::InitError,
+    >,
+{
+    type Request = A::Request;
+    type Response = A::Response;
+    type Error = A::Error;
+    type InitError = A::InitError;
+    type Service = EitherService<A::Service, B::Service>;
+    type Future = EitherNewService<A, B>;
+
+    fn new_service(&self) -> Self::Future {
+        match self {
+            Either::A(ref inner) => EitherNewService::A(inner.new_service()),
+            Either::B(ref inner) => EitherNewService::B(inner.new_service()),
+        }
+    }
+}
+
+#[doc(hidden)]
+pub enum EitherNewService<A: NewService, B: NewService> {
+    A(A::Future),
+    B(B::Future),
+}
+
+impl<A, B> Future for EitherNewService<A, B>
+where
+    A: NewService,
+    B: NewService<
+        Request = A::Request,
+        Response = A::Response,
+        Error = A::Error,
+        InitError = A::InitError,
+    >,
+{
+    type Item = EitherService<A::Service, B::Service>;
+    type Error = A::InitError;
+
+    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
+        match self {
+            EitherNewService::A(ref mut fut) => {
+                let service = try_ready!(fut.poll());
+                Ok(Async::Ready(EitherService::A(service)))
+            }
+            EitherNewService::B(ref mut fut) => {
+                let service = try_ready!(fut.poll());
+                Ok(Async::Ready(EitherService::B(service)))
+            }
+        }
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index a1204730..f6262791 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -58,6 +58,7 @@ extern crate webpki_roots;
 pub mod cloneable;
 pub mod connector;
 pub mod counter;
+pub mod either;
 pub mod framed;
 pub mod inflight;
 pub mod keepalive;
diff --git a/src/server/services.rs b/src/server/services.rs
index a2dad1ba..43ba8ce0 100644
--- a/src/server/services.rs
+++ b/src/server/services.rs
@@ -12,8 +12,11 @@ use service::{NewService, Service};
 
 /// Server message
 pub enum ServerMessage {
+    /// New stream
     Connect(net::TcpStream),
+    /// Gracefull shutdown
     Shutdown(Duration),
+    /// Force shutdown
     ForceShutdown,
 }
 
@@ -220,6 +223,18 @@ impl InternalServiceFactory for Box<InternalServiceFactory> {
     }
 }
 
+impl<F, T> ServiceFactory for F
+where
+    F: Fn() -> T + Send + Clone + 'static,
+    T: NewService<Request = ServerMessage, Response = (), Error = (), InitError = ()>,
+{
+    type NewService = T;
+
+    fn create(&self) -> T {
+        (self)()
+    }
+}
+
 impl<F, T> StreamServiceFactory for F
 where
     F: Fn() -> T + Send + Clone + 'static,