Subsonic API: added common answer fields

src/libs/subsonic/impl/ProtocolVersion.hpp

@@ -31,6 +31,7 @@ namespace API::Subsonic
     };
 
     static inline constexpr ProtocolVersion defaultServerProtocolVersion{ 1, 16, 0 };
+    static inline constexpr std::string_view serverVersion{ "1" };
 }
 
 namespace StringUtils

src/libs/subsonic/impl/SubsonicResponse.cpp

@@ -130,7 +130,11 @@ namespace API::Subsonic
 
         responseNode.setAttribute("status", "ok");
         responseNode.setVersionAttribute(protocolVersion);
-        responseNode.setAttribute("type", "lms"); // non standard field to ease client hacks
+
+        // OpenSubsonic mandatory fields
+        responseNode.setAttribute("type", "lms");
+        responseNode.setAttribute("serverVersion", serverVersion);
+        responseNode.setAttribute("openSubsonic", true);
 
         return response;
     }