Fix websockets failing on Firefox (#76)

Axum expected the `Connection` header to be _exactly_ `upgrade`. Turns
out thats a bit too strict as this didn't work in Firefox.

Turns out `Connection` just has to contain `upgrade`. At least that is
what [warp does](https://github.com/seanmonstar/warp/blob/master/src/filters/ws.rs#L46).

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Improve documentation for routing ([#71](https://github.com/tokio-rs/axum/pull/71))
 - Clarify required response body type when routing to `tower::Service`s ([#69](https://github.com/tokio-rs/axum/pull/69))
 - Add `axum::body::box_body` to converting an `http_body::Body` to `axum::body::BoxBody` ([#69](https://github.com/tokio-rs/axum/pull/69))
+- Fix WebSockets failing on Firefox ([#76](https://github.com/tokio-rs/axum/pull/76))
 
 ## Breaking changes
 

src/ws/mod.rs

@@ -236,29 +236,21 @@ where
                 return response(StatusCode::NOT_FOUND, "Request method must be `GET`");
             }
 
-            if !header_eq(
-                &req,
-                header::CONNECTION,
-                HeaderValue::from_static("upgrade"),
-            ) {
+            if !header_contains(&req, header::CONNECTION, "upgrade") {
                 return response(
                     StatusCode::BAD_REQUEST,
                     "Connection header did not include 'upgrade'",
                 );
             }
 
-            if !header_eq(&req, header::UPGRADE, HeaderValue::from_static("websocket")) {
+            if !header_eq(&req, header::UPGRADE, "websocket") {
                 return response(
                     StatusCode::BAD_REQUEST,
                     "`Upgrade` header did not include 'websocket'",
                 );
             }
 
-            if !header_eq(
-                &req,
-                header::SEC_WEBSOCKET_VERSION,
-                HeaderValue::from_static("13"),
-            ) {
+            if !header_eq(&req, header::SEC_WEBSOCKET_VERSION, "13") {
                 return response(
                     StatusCode::BAD_REQUEST,
                     "`Sec-Websocket-Version` header did not include '13'",
@@ -320,6 +312,8 @@ where
 }
 
 fn response<E>(status: StatusCode, body: &'static str) -> Result<Response<BoxBody>, E> {
+    dbg!((status, body));
+
     let res = Response::builder()
         .status(status)
         .body(box_body(Full::from(body)))
@@ -327,7 +321,7 @@ fn response<E>(status: StatusCode, body: &'static str) -> Result<Response<BoxBod
     Ok(res)
 }
 
-fn header_eq<B>(req: &Request<B>, key: HeaderName, value: HeaderValue) -> bool {
+fn header_eq<B>(req: &Request<B>, key: HeaderName, value: &'static str) -> bool {
     if let Some(header) = req.headers().get(&key) {
         header.as_bytes().eq_ignore_ascii_case(value.as_bytes())
     } else {
@@ -335,6 +329,20 @@ fn header_eq<B>(req: &Request<B>, key: HeaderName, value: HeaderValue) -> bool {
     }
 }
 
+fn header_contains<B>(req: &Request<B>, key: HeaderName, value: &'static str) -> bool {
+    let header = if let Some(header) = req.headers().get(&key) {
+        header
+    } else {
+        return false;
+    };
+
+    if let Ok(header) = std::str::from_utf8(header.as_bytes()) {
+        header.to_ascii_lowercase().contains(value)
+    } else {
+        false
+    }
+}
+
 fn sign(key: &[u8]) -> HeaderValue {
     let mut sha1 = Sha1::default();
     sha1.update(key);