diff --git a/std/json.nas b/std/json.nas
index 82843cc8..6e4d42b0 100644
--- a/std/json.nas
+++ b/std/json.nas
@@ -30,7 +30,6 @@ var _j_content = [
 var _parse_error = 0;
 
 var parse = func() {
-    _parse_error = 0;
     var text = "";
     var line = 1;
     var text_size = 0;
@@ -226,6 +225,7 @@ var parse = func() {
     }
 
     return func(source) {
+        _parse_error = 0;
         if(typeof(source)!="str") {
             println("json::parse: must use string but get", typeof(str));
             _parse_error += 1;
@@ -247,8 +247,10 @@ var parse = func() {
 }();
 
 var stringify = func(object) {
+    _parse_error = 0;
     var object_type = typeof(object);
     if(object_type!="hash" and object_type!="vec" and object_type!="namespace") {
+        _parse_error += 1;
         println("json::stringify: must use hashmap or vector, but get ", typeof(object));
         return "[]";
     }
diff --git a/tools/fgfs_props_getter.nas b/tools/fgfs_props_getter.nas
index c19fa2ae..e0cfa87a 100644
--- a/tools/fgfs_props_getter.nas
+++ b/tools/fgfs_props_getter.nas
@@ -6,38 +6,61 @@
 use module.libsock;
 use std.json;
 
-var socket = libsock.socket;
-var sd = socket.socket(socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_TCP);
+var new_getter = func(hostname, port) {
+    var socket = libsock.socket;
+    var sd = socket.socket(
+        socket.AF_INET,
+        socket.SOCK_STREAM,
+        socket.IPPROTO_TCP
+    );
 
-while((var err = socket.connect(sd, "127.0.0.1", 5500))==socket.SOCKET_ERROR) {
-    println("[", os.time(), "] connect to 127.0.0.1:5500 failed: ", socket.errno());
-    unix.sleep(1);
-}
-println("[", os.time(), "] connect to 127.0.0.1:5500 succeeded");
+    while((var err = socket.connect(sd, hostname, port))==socket.SOCKET_ERROR) {
+        println(
+            "[", os.time(), "] connect to ",
+            hostname, ":", port, " failed: ",
+            socket.errno()
+        );
+        unix.sleep(1);
+    }
+    println("[", os.time(), "] connect to ", hostname, ":", port, " succeeded");
 
+    var getprop = func(path) {
+        var header = "GET /json"~path~" HTTP/1.1\n\r\n";
+        var res = socket.send(sd, header);
+        var message = socket.recv(sd, 1024);
 
-var header = "GET /json/ HTTP/1.1\n\r\n";
-var res = socket.send(sd, header);
-var message = socket.recv(sd, 1024);
+        var total_source = message.str;
+        while(message.size!=0) {
+            message = socket.recv(sd, 1024);
+            total_source ~= message.str;
+        }
 
-var total_source = message.str;
-var total_size = message.size;
+        var begin_position = find("{", total_source);
+        var end_position = find("0\r\n\r\n", total_source);
+        var props = substr(total_source, begin_position, end_position-begin_position);
+        props = json.parse(props);
+        json.check_error();
+        if (size(props)==0) {
+            println("getprop: node \"", path, "\" not found");
+        }
 
-while(message.size==1024) {
-    message = socket.recv(sd, 1024);
-    total_source ~= message.str;
-    total_size += message.size;
-}
+        return props;
+    }
 
-socket.closesocket(sd);
+    var close = func {
+        socket.closesocket(sd);
+    }
 
-var A3E_position = find("{", total_source);
-var end_0_position = find("0\r\n\r\n", total_source);
-var props = substr(total_source, A3E_position, end_0_position-A3E_position);
-props = json.parse(props);
-json.check_error();
+    return {
+        getprop: getprop,
+        close: close
+    };
+}
 
-var dfs = func(tree, indent = "") {
+var dump = func(tree, indent = "") {
+    if (size(tree)==0) {
+        return;
+    }
     println(indent, "---------");
     println(indent, "path : \"", tree.path, "\"");
     println(indent, "name : \"", tree.name, "\"");
@@ -49,10 +72,29 @@ var dfs = func(tree, indent = "") {
     if (contains(tree, "children")) {
         println(indent, "children :");
         foreach(var i; tree.children) {
-            dfs(i, indent~"  ");
+            dump(i, indent~"  ");
         }
     }
+}
 
+if (size(arg)<2) {
+    println("require hostname and port");
+    exit(-1);
 }
+if (size(arg)>2) {
+    println("too many arguments, only require hostname and port");
+    exit(-1);
+}
+
+var getter = new_getter(arg[0], num(arg[1]));
+
+var get_props = func(path = "/") {
+    var props = getter.getprop(path);
+    dump(props);
+}
+
+get_props();
+get_props("/e-tron/dialog/config");
+get_props("/e-tron/dialog/config/a");
 
-dfs(props);
\ No newline at end of file
+getter.close();
\ No newline at end of file