Handle case where params is null (#65)

* if request does not have parameters, set params to empty [{}]

src/rpc/RPC.cpp

@@ -37,7 +37,7 @@ make_HttpContext(
     if (command == "subscribe" || command == "unsubscribe")
         return {};
 
-    if (!request.contains("params") || !request.at("params").is_array())
+    if (!request.at("params").is_array())
         return {};
 
     boost::json::array const& array = request.at("params").as_array();

src/webserver/HttpBase.h

@@ -111,6 +111,9 @@ handle_request(
         try
         {
             request = boost::json::parse(req.body()).as_object();
+            
+            if (!request.contains("params"))
+                request["params"] = boost::json::array({ boost::json::object {} });
         }
         catch (std::runtime_error const& e)
         {