Validate the headers of WebSocket handshake request loosely #1602

Author: JamesChenX

turms-gateway/src/main/java/im/turms/gateway/access/client/websocket/WebSocketServerFactory.java

@@ -18,7 +18,6 @@
 package im.turms.gateway.access.client.websocket;
 
 import java.net.InetSocketAddress;
-import java.util.List;
 import jakarta.annotation.Nullable;
 
 import io.netty.buffer.ByteBuf;
@@ -228,14 +227,13 @@ private static HttpResponseStatus validateHandshakeRequest(HttpServerRequest req
                             + method
                             + "' not supported");
         }
-        if (!"WebSocket".equalsIgnoreCase(headers.get(UPGRADE))) {
+        if (!headers.containsValue(UPGRADE, "websocket", true)) {
             return new HttpResponseStatus(
                     HttpResponseStatus.BAD_REQUEST.code(),
                     "Invalid 'Upgrade' header: "
                             + headers);
         }
-        List<String> connectionValue = headers.getAll(CONNECTION);
-        if (!connectionValue.contains("Upgrade") && !connectionValue.contains("upgrade")) {
+        if (!headers.containsValue(CONNECTION, "upgrade", true)) {
             return new HttpResponseStatus(
                     HttpResponseStatus.BAD_REQUEST.code(),
                     "Invalid 'Connection' header: "