fix config function

Author: SimonDanisch

src/providers/generic_http.jl

@@ -158,11 +158,11 @@ const webio_server_config = Ref{typeof((url = "", http_port = 0, ws_url = ""))}(
 
 function global_server_config()
     if !isassigned(webio_server_config)
-        webio_server_config[] = (
-            url = get(ENV, "WEBIO_SERVER_HOST_URL", "127.0.0.1"),
-            http_port = parse(Int, get(ENV, "WEBIO_HTTP_PORT", "8081")),
-            ws_url = get(ENV, "WEBIO_WEBSOCKT_URL", url * ":" * http_port * "/webio_websocket/")
-        )
+        url = get(ENV, "WEBIO_SERVER_HOST_URL", "127.0.0.1")
+        http_port = parse(Int, get(ENV, "WEBIO_HTTP_PORT", "8081"))
+        ws_default = string(url, ":", http_port, "/webio_websocket/")
+        ws_url = get(ENV, "WEBIO_WEBSOCKT_URL", ws_default)
+        webio_server_config[] = (url = url, http_port = http_port, ws_url = ws_url)
     end
     webio_server_config[]
 end