diff --git a/src/application.rs b/src/application.rs
index 5555ee39..e53382de 100644
--- a/src/application.rs
+++ b/src/application.rs
@@ -26,7 +26,8 @@ pub struct HttpApplication<S = ()> {
     middlewares: Rc<RefCell<Vec<Box<Middleware<S>>>>>,
 }
 
-pub(crate) struct Inner<S> {
+#[doc(hidden)]
+pub struct Inner<S> {
     prefix: usize,
     default: ResourceHandler<S>,
     encoding: ContentEncoding,
@@ -136,7 +137,11 @@ impl<S: 'static> HttpApplication<S> {
 }
 
 impl<S: 'static> HttpHandler for HttpApplication<S> {
-    fn handle(&mut self, req: HttpRequest) -> Result<Box<HttpHandlerTask>, HttpRequest> {
+    type Task = Pipeline<S, Inner<S>>;
+
+    fn handle(
+        &mut self, req: HttpRequest,
+    ) -> Result<Pipeline<S, Inner<S>>, HttpRequest> {
         let m = {
             let path = req.path();
             path.starts_with(&self.prefix)
@@ -157,12 +162,7 @@ impl<S: 'static> HttpHandler for HttpApplication<S> {
 
             let tp = self.get_handler(&mut req2);
             let inner = Rc::clone(&self.inner);
-            Ok(Box::new(Pipeline::new(
-                req2,
-                Rc::clone(&self.middlewares),
-                inner,
-                tp,
-            )))
+            Ok(Pipeline::new(req2, Rc::clone(&self.middlewares), inner, tp))
         } else {
             Err(req)
         }
@@ -679,8 +679,23 @@ where
     /// # });
     /// }
     /// ```
-    pub fn boxed(mut self) -> Box<HttpHandler> {
-        Box::new(self.finish())
+    pub fn boxed(mut self) -> Box<HttpHandler<Task = Box<HttpHandlerTask>>> {
+        Box::new(BoxedApplication { app: self.finish() })
+    }
+}
+
+struct BoxedApplication<S> {
+    app: HttpApplication<S>,
+}
+
+impl<S: 'static> HttpHandler for BoxedApplication<S> {
+    type Task = Box<HttpHandlerTask>;
+
+    fn handle(&mut self, req: HttpRequest) -> Result<Self::Task, HttpRequest> {
+        self.app.handle(req).map(|t| {
+            let task: Self::Task = Box::new(t);
+            task
+        })
     }
 }
 
@@ -798,9 +813,7 @@ mod tests {
 
     #[test]
     fn test_handler() {
-        let mut app = App::new()
-            .handler("/test", |_| HttpResponse::Ok())
-            .finish();
+        let mut app = App::new().handler("/test", |_| HttpResponse::Ok()).finish();
 
         let req = TestRequest::with_uri("/test").finish();
         let resp = app.run(req);
@@ -825,9 +838,7 @@ mod tests {
 
     #[test]
     fn test_handler2() {
-        let mut app = App::new()
-            .handler("test", |_| HttpResponse::Ok())
-            .finish();
+        let mut app = App::new().handler("test", |_| HttpResponse::Ok()).finish();
 
         let req = TestRequest::with_uri("/test").finish();
         let resp = app.run(req);
@@ -881,29 +892,21 @@ mod tests {
     #[test]
     fn test_route() {
         let mut app = App::new()
-            .route("/test", Method::GET, |_: HttpRequest| {
-                HttpResponse::Ok()
-            })
+            .route("/test", Method::GET, |_: HttpRequest| HttpResponse::Ok())
             .route("/test", Method::POST, |_: HttpRequest| {
                 HttpResponse::Created()
             })
             .finish();
 
-        let req = TestRequest::with_uri("/test")
-            .method(Method::GET)
-            .finish();
+        let req = TestRequest::with_uri("/test").method(Method::GET).finish();
         let resp = app.run(req);
         assert_eq!(resp.as_msg().status(), StatusCode::OK);
 
-        let req = TestRequest::with_uri("/test")
-            .method(Method::POST)
-            .finish();
+        let req = TestRequest::with_uri("/test").method(Method::POST).finish();
         let resp = app.run(req);
         assert_eq!(resp.as_msg().status(), StatusCode::CREATED);
 
-        let req = TestRequest::with_uri("/test")
-            .method(Method::HEAD)
-            .finish();
+        let req = TestRequest::with_uri("/test").method(Method::HEAD).finish();
         let resp = app.run(req);
         assert_eq!(resp.as_msg().status(), StatusCode::NOT_FOUND);
     }
@@ -972,9 +975,6 @@ mod tests {
         let req = TestRequest::with_uri("/some").finish();
         let resp = app.run(req);
         assert_eq!(resp.as_msg().status(), StatusCode::OK);
-        assert_eq!(
-            resp.as_msg().body(),
-            &Body::Binary(Binary::Slice(b"some"))
-        );
+        assert_eq!(resp.as_msg().body(), &Body::Binary(Binary::Slice(b"some")));
     }
 }
diff --git a/src/pipeline.rs b/src/pipeline.rs
index e5eb51d5..d08a739d 100644
--- a/src/pipeline.rs
+++ b/src/pipeline.rs
@@ -18,14 +18,16 @@ use httpresponse::HttpResponse;
 use middleware::{Finished, Middleware, Response, Started};
 use server::{HttpHandlerTask, Writer, WriterState};
 
+#[doc(hidden)]
 #[derive(Debug, Clone, Copy)]
-pub(crate) enum HandlerType {
+pub enum HandlerType {
     Normal(usize),
     Handler(usize),
     Default,
 }
 
-pub(crate) trait PipelineHandler<S> {
+#[doc(hidden)]
+pub trait PipelineHandler<S> {
     fn encoding(&self) -> ContentEncoding;
 
     fn handle(
@@ -33,7 +35,8 @@ pub(crate) trait PipelineHandler<S> {
     ) -> AsyncResult<HttpResponse>;
 }
 
-pub(crate) struct Pipeline<S, H>(PipelineInfo<S>, PipelineState<S, H>);
+#[doc(hidden)]
+pub struct Pipeline<S, H>(PipelineInfo<S>, PipelineState<S, H>);
 
 enum PipelineState<S, H> {
     None,
@@ -207,7 +210,7 @@ impl<S: 'static, H: PipelineHandler<S>> HttpHandlerTask for Pipeline<S, H> {
         }
     }
 
-    fn poll(&mut self) -> Poll<(), Error> {
+    fn poll_completed(&mut self) -> Poll<(), Error> {
         let info: &mut PipelineInfo<_> = unsafe { &mut *(&mut self.0 as *mut _) };
 
         loop {
diff --git a/src/server/channel.rs b/src/server/channel.rs
index 34f6733c..a38ecc93 100644
--- a/src/server/channel.rs
+++ b/src/server/channel.rs
@@ -11,7 +11,7 @@ use super::{h1, h2, utils, HttpHandler, IoStream};
 
 const HTTP2_PREFACE: [u8; 14] = *b"PRI * HTTP/2.0";
 
-enum HttpProtocol<T: IoStream, H: 'static> {
+enum HttpProtocol<T: IoStream, H: HttpHandler + 'static> {
     H1(h1::Http1<T, H>),
     H2(h2::Http2<T, H>),
     Unknown(Rc<WorkerSettings<H>>, Option<SocketAddr>, T, BytesMut),
diff --git a/src/server/h1.rs b/src/server/h1.rs
index 689d64dc..ababda6b 100644
--- a/src/server/h1.rs
+++ b/src/server/h1.rs
@@ -8,7 +8,7 @@ use bytes::{BufMut, BytesMut};
 use futures::{Async, Future, Poll};
 use tokio_timer::Delay;
 
-use error::PayloadError;
+use error::{Error, PayloadError};
 use httprequest::HttpRequest;
 use httpresponse::HttpResponse;
 use payload::{Payload, PayloadStatus, PayloadWriter};
@@ -43,7 +43,7 @@ bitflags! {
     }
 }
 
-pub(crate) struct Http1<T: IoStream, H: 'static> {
+pub(crate) struct Http1<T: IoStream, H: HttpHandler + 'static> {
     flags: Flags,
     settings: Rc<WorkerSettings<H>>,
     addr: Option<SocketAddr>,
@@ -51,12 +51,38 @@ pub(crate) struct Http1<T: IoStream, H: 'static> {
     decoder: H1Decoder,
     payload: Option<PayloadType>,
     buf: BytesMut,
-    tasks: VecDeque<Entry>,
+    tasks: VecDeque<Entry<H>>,
     keepalive_timer: Option<Delay>,
 }
 
-struct Entry {
-    pipe: Box<HttpHandlerTask>,
+enum EntryPipe<H: HttpHandler> {
+    Task(H::Task),
+    Error(Box<HttpHandlerTask>),
+}
+
+impl<H: HttpHandler> EntryPipe<H> {
+    fn disconnected(&mut self) {
+        match *self {
+            EntryPipe::Task(ref mut task) => task.disconnected(),
+            EntryPipe::Error(ref mut task) => task.disconnected(),
+        }
+    }
+    fn poll_io(&mut self, io: &mut Writer) -> Poll<bool, Error> {
+        match *self {
+            EntryPipe::Task(ref mut task) => task.poll_io(io),
+            EntryPipe::Error(ref mut task) => task.poll_io(io),
+        }
+    }
+    fn poll_completed(&mut self) -> Poll<(), Error> {
+        match *self {
+            EntryPipe::Task(ref mut task) => task.poll_completed(),
+            EntryPipe::Error(ref mut task) => task.poll_completed(),
+        }
+    }
+}
+
+struct Entry<H: HttpHandler> {
+    pipe: EntryPipe<H>,
     flags: EntryFlags,
 }
 
@@ -181,7 +207,7 @@ where
         let mut io = false;
         let mut idx = 0;
         while idx < self.tasks.len() {
-            let item: &mut Entry = unsafe { &mut *(&mut self.tasks[idx] as *mut _) };
+            let item: &mut Entry<H> = unsafe { &mut *(&mut self.tasks[idx] as *mut _) };
 
             // only one task can do io operation in http/1
             if !io && !item.flags.contains(EntryFlags::EOF) {
@@ -232,7 +258,7 @@ where
                     }
                 }
             } else if !item.flags.contains(EntryFlags::FINISHED) {
-                match item.pipe.poll() {
+                match item.pipe.poll_completed() {
                     Ok(Async::NotReady) => (),
                     Ok(Async::Ready(_)) => item.flags.insert(EntryFlags::FINISHED),
                     Err(err) => {
@@ -342,7 +368,7 @@ where
 
                                             if !ready {
                                                 let item = Entry {
-                                                    pipe,
+                                                    pipe: EntryPipe::Task(pipe),
                                                     flags: EntryFlags::EOF,
                                                 };
                                                 self.tasks.push_back(item);
@@ -358,7 +384,7 @@ where
                                     }
                                 }
                                 self.tasks.push_back(Entry {
-                                    pipe,
+                                    pipe: EntryPipe::Task(pipe),
                                     flags: EntryFlags::empty(),
                                 });
                                 continue 'outer;
@@ -369,7 +395,9 @@ where
 
                     // handler is not found
                     self.tasks.push_back(Entry {
-                        pipe: Pipeline::error(HttpResponse::NotFound()),
+                        pipe: EntryPipe::Error(
+                            Pipeline::error(HttpResponse::NotFound()),
+                        ),
                         flags: EntryFlags::empty(),
                     });
                 }
diff --git a/src/server/h2.rs b/src/server/h2.rs
index e194bc7d..993376ef 100644
--- a/src/server/h2.rs
+++ b/src/server/h2.rs
@@ -15,7 +15,7 @@ use modhttp::request::Parts;
 use tokio_io::{AsyncRead, AsyncWrite};
 use tokio_timer::Delay;
 
-use error::PayloadError;
+use error::{Error, PayloadError};
 use httpmessage::HttpMessage;
 use httprequest::HttpRequest;
 use httpresponse::HttpResponse;
@@ -38,7 +38,7 @@ bitflags! {
 pub(crate) struct Http2<T, H>
 where
     T: AsyncRead + AsyncWrite + 'static,
-    H: 'static,
+    H: HttpHandler + 'static,
 {
     flags: Flags,
     settings: Rc<WorkerSettings<H>>,
@@ -142,7 +142,7 @@ where
                             break;
                         }
                     } else if !item.flags.contains(EntryFlags::FINISHED) {
-                        match item.task.poll() {
+                        match item.task.poll_completed() {
                             Ok(Async::NotReady) => (),
                             Ok(Async::Ready(_)) => {
                                 not_ready = false;
@@ -288,15 +288,41 @@ bitflags! {
     }
 }
 
-struct Entry<H: 'static> {
-    task: Box<HttpHandlerTask>,
+enum EntryPipe<H: HttpHandler> {
+    Task(H::Task),
+    Error(Box<HttpHandlerTask>),
+}
+
+impl<H: HttpHandler> EntryPipe<H> {
+    fn disconnected(&mut self) {
+        match *self {
+            EntryPipe::Task(ref mut task) => task.disconnected(),
+            EntryPipe::Error(ref mut task) => task.disconnected(),
+        }
+    }
+    fn poll_io(&mut self, io: &mut Writer) -> Poll<bool, Error> {
+        match *self {
+            EntryPipe::Task(ref mut task) => task.poll_io(io),
+            EntryPipe::Error(ref mut task) => task.poll_io(io),
+        }
+    }
+    fn poll_completed(&mut self) -> Poll<(), Error> {
+        match *self {
+            EntryPipe::Task(ref mut task) => task.poll_completed(),
+            EntryPipe::Error(ref mut task) => task.poll_completed(),
+        }
+    }
+}
+
+struct Entry<H: HttpHandler + 'static> {
+    task: EntryPipe<H>,
     payload: PayloadType,
     recv: RecvStream,
     stream: H2Writer<H>,
     flags: EntryFlags,
 }
 
-impl<H: 'static> Entry<H> {
+impl<H: HttpHandler + 'static> Entry<H> {
     fn new(
         parts: Parts, recv: RecvStream, resp: SendResponse<Bytes>,
         addr: Option<SocketAddr>, settings: &Rc<WorkerSettings<H>>,
@@ -333,7 +359,9 @@ impl<H: 'static> Entry<H> {
         }
 
         Entry {
-            task: task.unwrap_or_else(|| Pipeline::error(HttpResponse::NotFound())),
+            task: task.map(EntryPipe::Task).unwrap_or_else(|| {
+                EntryPipe::Error(Pipeline::error(HttpResponse::NotFound()))
+            }),
             payload: psender,
             stream: H2Writer::new(
                 resp,
diff --git a/src/server/mod.rs b/src/server/mod.rs
index 82ba24e2..91b4d1fa 100644
--- a/src/server/mod.rs
+++ b/src/server/mod.rs
@@ -122,20 +122,25 @@ impl Message for StopServer {
 /// Low level http request handler
 #[allow(unused_variables)]
 pub trait HttpHandler: 'static {
+    /// Request handling task
+    type Task: HttpHandlerTask;
+
     /// Handle request
-    fn handle(&mut self, req: HttpRequest) -> Result<Box<HttpHandlerTask>, HttpRequest>;
+    fn handle(&mut self, req: HttpRequest) -> Result<Self::Task, HttpRequest>;
 }
 
-impl HttpHandler for Box<HttpHandler> {
+impl HttpHandler for Box<HttpHandler<Task = Box<HttpHandlerTask>>> {
+    type Task = Box<HttpHandlerTask>;
+
     fn handle(&mut self, req: HttpRequest) -> Result<Box<HttpHandlerTask>, HttpRequest> {
         self.as_mut().handle(req)
     }
 }
 
-#[doc(hidden)]
+/// Low level http request handler
 pub trait HttpHandlerTask {
     /// Poll task, this method is used before or after *io* object is available
-    fn poll(&mut self) -> Poll<(), Error> {
+    fn poll_completed(&mut self) -> Poll<(), Error> {
         Ok(Async::Ready(()))
     }
 
@@ -146,6 +151,12 @@ pub trait HttpHandlerTask {
     fn disconnected(&mut self) {}
 }
 
+impl HttpHandlerTask for Box<HttpHandlerTask> {
+    fn poll_io(&mut self, io: &mut Writer) -> Poll<bool, Error> {
+        self.as_mut().poll_io(io)
+    }
+}
+
 /// Conversion helper trait
 pub trait IntoHttpHandler {
     /// The associated type which is result of conversion.