webui: configs: Some minor fixes

* configs.py/_set_configs(): Also return the original data if the input
  values failed the validation;
* setServerConfigs(): Success callback also reset value if the input
  value failed pass the server-side validation;
* getServerConfigs(): Return "undefined" if key does not exists.

2 files changed, 22 insertions, 9 deletions

diff --git a/fg21sim/webui/handlers/configs.py b/fg21sim/webui/handlers/configs.py
index 296bd11..857138b 100644
--- a/fg21sim/webui/handlers/configs.py
+++ b/fg21sim/webui/handlers/configs.py
@@ -99,7 +99,7 @@ class ConfigsAJAXHandler(BaseRequestHandler):
         if action == "set":
             # Set the values of the specified options
             try:
-                errors = self._set_configs(data=request["data"])
+                data, errors = self._set_configs(request["data"])
                 success = True
             except KeyError:
                 success = False
@@ -198,10 +198,15 @@ class ConfigsAJAXHandler(BaseRequestHandler):
 
         Returns
         -------
+        data_orig : dict
+            When the supplied value failed to pass the specification
+            validation, then its original value was returned to the client
+            to reset its value.
         errors : dict
             When error occurs (e.g., invalid key, invalid values), then the
             specific errors with details are stored in this dictionary.
         """
+        data_orig = {}
         errors = {}
         for key, value in data.items():
             if key in ["workdir", "configfile"]:
@@ -215,10 +220,13 @@ class ConfigsAJAXHandler(BaseRequestHandler):
             else:
                 try:
                     self.configs.setn(key, value)
-                except (KeyError, ConfigError) as e:
+                except KeyError as e:
+                    errors[key] = str(e)
+                except ConfigError as e:
+                    data_orig[key] = self.configs.getn(key)
                     errors[key] = str(e)
         #
-        return errors
+        return (data_orig, errors)
 
     def _reset_configs(self):
         """Reset the configurations to the defaults."""
diff --git a/fg21sim/webui/static/js/configs.js b/fg21sim/webui/static/js/configs.js
index f7e3731..f321881 100644
--- a/fg21sim/webui/static/js/configs.js
+++ b/fg21sim/webui/static/js/configs.js
@@ -118,8 +118,9 @@ var resetFormConfigs = function () {
  *
  * @param {String} name - The name of filed name
  *
- * @returns value - value of the option field
- *                  + `null` if the field not exists or empty (no value)
+ * @returns value - value of the configuration option field
+ *                  + `null` if the field is empty (no value)
+ *                  + `undefined` if the field does not exists
  */
 var getFormConfigSingle = function (name) {
   var value = null;
@@ -143,8 +144,11 @@ var getFormConfigSingle = function (name) {
         value = target.filter(":checked").map(
           function () { return $(this).val(); }).get();
       } else if (target.is(":text") && target.data("type") === "array") {
-        // Convert back to Array
+        // Convert comma-separated string back to Array
         value = target.val().split(/\s*,\s*/);
+        if (value.length === 1 && value[0] === "") {
+          value = [];  // Empty Array
+        }
       } else {
         value = target.val();
       }
@@ -153,6 +157,7 @@ var getFormConfigSingle = function (name) {
         value = null;
       }
     } else {
+      value = undefined;
       console.error("No such element:", selector);
     }
   }
@@ -241,11 +246,11 @@ var setFormConfigSingle = function (name, value) {
 var setFormConfigs = function (data, errors) {
   // Set the values of form field to the input configurations data
   $.each(data, function (name, value) {
-    if (value == null) {
+    if (value === null) {
       value = "";  // Default to empty string
     }
     var val_old = getFormConfigSingle(name);
-    if (val_old !== value) {
+    if (typeof val_old !== "undefined" && val_old !== value) {
       setFormConfigSingle(name, value);
       console.log("Set input '" + name + "' to:", value, " <-", val_old);
     }
@@ -388,7 +393,7 @@ var setServerConfigs = function (url, data) {
   data = typeof data !== "undefined" ? data : {};
   return $.postJSON(url, {action: "set", data: data},
                     function (response) {
-                      setFormConfigs({}, response.errors);
+                      setFormConfigs(response.data, response.errors);
                     })
     .fail(function (jqxhr) {
       var modalData = {};