add support for specifying protocols on websocket handshake (#835)

* add support for specifying protocols on websocket handshake

* separated the handshake function with and without protocols
changed protocols type from Vec<&str> to [&str]

actix-web-actors/src/ws.rs

@@ -60,15 +60,43 @@ where
     Ok((addr, res.streaming(out_stream)))
 }
 
+/// Do websocket handshake and start ws actor.
+///
+/// `protocols` is a sequence of known protocols.
+pub fn start_with_protocols<A, T>(
+    actor: A,
+    protocols: &[&str],
+    req: &HttpRequest,
+    stream: T,
+) -> Result<HttpResponse, Error>
+where
+    A: Actor<Context = WebsocketContext<A>> + StreamHandler<Message, ProtocolError>,
+    T: Stream<Item = Bytes, Error = PayloadError> + 'static,
+{
+    let mut res = handshake_with_protocols(req, protocols)?;
+    Ok(res.streaming(WebsocketContext::create(actor, stream)))
+}
+
+/// Prepare `WebSocket` handshake response.
+///
+/// This function returns handshake `HttpResponse`, ready to send to peer.
+/// It does not perform any IO.
+pub fn handshake(req: &HttpRequest) -> Result<HttpResponseBuilder, HandshakeError> {
+    handshake_with_protocols(req, &[])
+}
+
 /// Prepare `WebSocket` handshake response.
 ///
 /// This function returns handshake `HttpResponse`, ready to send to peer.
 /// It does not perform any IO.
 ///
-// /// `protocols` is a sequence of known protocols. On successful handshake,
+/// `protocols` is a sequence of known protocols. On successful handshake,
-// /// the returned response headers contain the first protocol in this list
+/// the returned response headers contain the first protocol in this list
-// /// which the server also knows.
+/// which the server also knows.
-pub fn handshake(req: &HttpRequest) -> Result<HttpResponseBuilder, HandshakeError> {
+pub fn handshake_with_protocols(
+    req: &HttpRequest,
+    protocols: &[&str],
+) -> Result<HttpResponseBuilder, HandshakeError> {
     // WebSocket accepts only GET
     if *req.method() != Method::GET {
         return Err(HandshakeError::GetMethodRequired);
@@ -117,11 +145,28 @@ pub fn handshake(req: &HttpRequest) -> Result<HttpResponseBuilder, HandshakeErro
         hash_key(key.as_ref())
     };
 
-    Ok(HttpResponse::build(StatusCode::SWITCHING_PROTOCOLS)
+    // check requested protocols
+    let protocol =
+        req.headers()
+            .get(&header::SEC_WEBSOCKET_PROTOCOL)
+            .and_then(|req_protocols| {
+                let req_protocols = req_protocols.to_str().ok()?;
+                req_protocols
+                    .split(", ")
+                    .find(|req_p| protocols.iter().any(|p| p == req_p))
+            });
+
+    let mut response = HttpResponse::build(StatusCode::SWITCHING_PROTOCOLS)
         .upgrade("websocket")
         .header(header::TRANSFER_ENCODING, "chunked")
         .header(header::SEC_WEBSOCKET_ACCEPT, key.as_str())
-        .take())
+        .take();
+
+    if let Some(protocol) = protocol {
+        response.header(&header::SEC_WEBSOCKET_PROTOCOL, protocol);
+    }
+
+    Ok(response)
 }
 
 /// Execution context for `WebSockets` actors
@@ -609,5 +654,87 @@ mod tests {
             StatusCode::SWITCHING_PROTOCOLS,
             handshake(&req).unwrap().finish().status()
         );
+
+        let req = TestRequest::default()
+            .header(
+                header::UPGRADE,
+                header::HeaderValue::from_static("websocket"),
+            )
+            .header(
+                header::CONNECTION,
+                header::HeaderValue::from_static("upgrade"),
+            )
+            .header(
+                header::SEC_WEBSOCKET_VERSION,
+                header::HeaderValue::from_static("13"),
+            )
+            .header(
+                header::SEC_WEBSOCKET_KEY,
+                header::HeaderValue::from_static("13"),
+            )
+            .header(
+                header::SEC_WEBSOCKET_PROTOCOL,
+                header::HeaderValue::from_static("graphql"),
+            )
+            .to_http_request();
+
+        let protocols = ["graphql"];
+
+        assert_eq!(
+            StatusCode::SWITCHING_PROTOCOLS,
+            handshake_with_protocols(&req, &protocols)
+                .unwrap()
+                .finish()
+                .status()
+        );
+        assert_eq!(
+            Some(&header::HeaderValue::from_static("graphql")),
+            handshake_with_protocols(&req, &protocols)
+                .unwrap()
+                .finish()
+                .headers()
+                .get(&header::SEC_WEBSOCKET_PROTOCOL)
+        );
+
+        let req = TestRequest::default()
+            .header(
+                header::UPGRADE,
+                header::HeaderValue::from_static("websocket"),
+            )
+            .header(
+                header::CONNECTION,
+                header::HeaderValue::from_static("upgrade"),
+            )
+            .header(
+                header::SEC_WEBSOCKET_VERSION,
+                header::HeaderValue::from_static("13"),
+            )
+            .header(
+                header::SEC_WEBSOCKET_KEY,
+                header::HeaderValue::from_static("13"),
+            )
+            .header(
+                header::SEC_WEBSOCKET_PROTOCOL,
+                header::HeaderValue::from_static("p1, p2, p3"),
+            )
+            .to_http_request();
+
+        let protocols = vec!["p3", "p2"];
+
+        assert_eq!(
+            StatusCode::SWITCHING_PROTOCOLS,
+            handshake_with_protocols(&req, &protocols)
+                .unwrap()
+                .finish()
+                .status()
+        );
+        assert_eq!(
+            Some(&header::HeaderValue::from_static("p2")),
+            handshake_with_protocols(&req, &protocols)
+                .unwrap()
+                .finish()
+                .headers()
+                .get(&header::SEC_WEBSOCKET_PROTOCOL)
+        );
     }
 }