strip IPv6 brackets before connecting to IP

src/lib.rs

@@ -377,12 +377,24 @@ where
 pub(crate) fn domain(
     request: &tungstenite::handshake::client::Request,
 ) -> Result<String, tungstenite::Error> {
-    match request.uri().host() {
-        Some(d) => Ok(d.to_string()),
-        None => Err(tungstenite::Error::Url(
-            tungstenite::error::UrlError::NoHostName,
-        )),
-    }
+    request
+        .uri()
+        .host()
+        .map(|host| {
+            // If host is an IPv6 address, it might be surrounded by brackets. These brackets are
+            // *not* part of a valid IP, so they must be stripped out.
+            //
+            // The URI from the request is guaranteed to be valid, so we don't need a separate
+            // check for the closing bracket.
+            let host = if host.starts_with('[') {
+                &host[1..host.len() - 1]
+            } else {
+                host
+            };
+
+            host.to_owned()
+        })
+        .ok_or_else(|| tungstenite::Error::Url(tungstenite::error::UrlError::NoHostName))
 }
 
 #[cfg(any(
@@ -407,3 +419,29 @@ pub(crate) fn port(
             tungstenite::error::UrlError::UnsupportedUrlScheme,
         ))
 }
+
+#[cfg(test)]
+mod tests {
+    #[cfg(any(
+        feature = "async-tls",
+        feature = "async-std-runtime",
+        feature = "tokio-runtime",
+        feature = "gio-runtime"
+    ))]
+    #[test]
+    fn domain_strips_ipv6_brackets() {
+        use tungstenite::client::IntoClientRequest;
+
+        let request = "ws://[::1]:80".into_client_request().unwrap();
+        assert_eq!(crate::domain(&request).unwrap(), "::1");
+    }
+
+    #[test]
+    fn requests_cannot_contain_invalid_uris() {
+        use tungstenite::client::IntoClientRequest;
+
+        assert!("ws://[".into_client_request().is_err());
+        assert!("ws://[blabla/bla".into_client_request().is_err());
+        assert!("ws://[::1/bla".into_client_request().is_err());
+    }
+}