refined error model (#2253)

actix-http/tests/test_ws.rs

@@ -1,11 +1,12 @@
 use std::{
     cell::Cell,
+    convert::Infallible,
     task::{Context, Poll},
 };
 
 use actix_codec::{AsyncRead, AsyncWrite, Framed};
 use actix_http::{
-    body::BodySize,
+    body::{AnyBody, BodySize},
     h1,
     ws::{self, CloseCode, Frame, Item, Message},
     Error, HttpService, Request, Response,
@@ -13,6 +14,7 @@ use actix_http::{
 use actix_http_test::test_server;
 use actix_service::{fn_factory, Service};
 use bytes::Bytes;
+use derive_more::{Display, Error, From};
 use futures_core::future::LocalBoxFuture;
 use futures_util::{SinkExt as _, StreamExt as _};
 
@@ -33,12 +35,39 @@ impl WsService {
     }
 }
 
+#[derive(Debug, Display, Error, From)]
+enum WsServiceError {
+    #[display(fmt = "http error")]
+    Http(actix_http::Error),
+
+    #[display(fmt = "ws handshake error")]
+    Ws(actix_http::ws::HandshakeError),
+
+    #[display(fmt = "io error")]
+    Io(std::io::Error),
+
+    #[display(fmt = "dispatcher error")]
+    Dispatcher,
+}
+
+impl From<WsServiceError> for Response<AnyBody> {
+    fn from(err: WsServiceError) -> Self {
+        match err {
+            WsServiceError::Http(err) => err.into(),
+            WsServiceError::Ws(err) => err.into(),
+            WsServiceError::Io(_err) => unreachable!(),
+            WsServiceError::Dispatcher => Response::internal_server_error()
+                .set_body(AnyBody::from(format!("{}", err))),
+        }
+    }
+}
+
 impl<T> Service<(Request, Framed<T, h1::Codec>)> for WsService
 where
     T: AsyncRead + AsyncWrite + Unpin + 'static,
 {
     type Response = ();
-    type Error = Error;
+    type Error = WsServiceError;
     type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;
 
     fn poll_ready(&self, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
@@ -56,7 +85,9 @@ where
 
             let framed = framed.replace_codec(ws::Codec::new());
 
-            ws::Dispatcher::with(framed, service).await?;
+            ws::Dispatcher::with(framed, service)
+                .await
+                .map_err(|_| WsServiceError::Dispatcher)?;
 
             Ok(())
         })
@@ -72,7 +103,7 @@ async fn service(msg: Frame) -> Result<Message, Error> {
         Frame::Binary(bin) => Message::Binary(bin),
         Frame::Continuation(item) => Message::Continuation(item),
         Frame::Close(reason) => Message::Close(reason),
-        _ => return Err(Error::from(ws::ProtocolError::BadOpCode)),
+        _ => return Err(ws::ProtocolError::BadOpCode.into()),
     };
 
     Ok(msg)
@@ -82,8 +113,10 @@ async fn service(msg: Frame) -> Result<Message, Error> {
 async fn test_simple() {
     let mut srv = test_server(|| {
         HttpService::build()
-            .upgrade(fn_factory(|| async { Ok::<_, ()>(WsService::new()) }))
-            .finish(|_| async { Ok::<_, ()>(Response::not_found()) })
+            .upgrade(fn_factory(|| async {
+                Ok::<_, Infallible>(WsService::new())
+            }))
+            .finish(|_| async { Ok::<_, Infallible>(Response::not_found()) })
             .tcp()
     })
     .await;