[gen] Allow an ajax request to return a message, carried as a custom HTTP header and retrieved by appy.js to display a message.

gen/wrappers/ToolWrapper.py

@@ -239,14 +239,16 @@ class ToolWrapper(AbstractWrapper):
 
     # The message that is shown when a user triggers an action.
     pxMessage = Px('''
-     <div var="messages=ztool.consumeMessages()" if="messages"
-          class=":inPopup and 'messagePopup message' or 'message'">
+     <div class=":inPopup and 'messagePopup message' or 'message'"
+          style="display:none" id="appyMessage">
       <!-- The icon for closing the message -->
       <img src=":url('close')" align=":dright" class="clickable"
            onclick="this.parentNode.style.display='none'"/>
       <!-- The message content -->
-      <x>::messages</x>
-     </div>''')
+      <div id="appyMessageContent"></div>
+     </div>
+     <script type="text/javascript" var="messages=ztool.consumeMessages()"
+             if="messages">::'showAppyMessage(%s)' % q(messages)</script>''')
 
     # The page footer.
     pxFooter = Px('''

gen/wrappers/__init__.py

@@ -632,10 +632,12 @@ class AbstractWrapper(object):
              x=resp.setHeader('Content-type', ztool.xhtmlEncoding);
              x=resp.setHeader('Expires', 'Thu, 11 Dec 1975 12:05:00 GMT+2');
              x=resp.setHeader('Content-Language', lang);
-             x=resp.setHeader('CacheControl', 'no-cache')">
+             x=resp.setHeader('Cache-Control', 'no-cache')">
 
       <!-- If an action is defined, execute it on p_zobj or on p_field. -->
-      <x if="action" var2="x=ztool.executeAjaxAction(action, obj, field)"></x>
+      <x if="action"
+         var2="msg=ztool.executeAjaxAction(action, obj, field) or '';
+               x=resp.setHeader('Appy-Message', msg)"></x>
 
       <!-- Then, call the PX on p_obj or on p_field. -->
       <x if="not field">:getattr(obj, px[0])</x>