Sunday, 24 March 2013

Inspecting nested Seaside components

I'm spending most of my time working on the tools to support a web port of a VW fat client application. We read windowSpecs and use them to build our own web 'widget' instances that know how to render themselves in Seaside using absolute positioning. This, combined with widget attribute meta data, has allowed us to automate most of the VW to Seaside port.

A challenge with this approach is that the Seaside views can get complex, with deeply nested subcanvas components. When debugging a button or input field widget, it's nice to not have to spend time getting to the specific instance. Seaside's Halos work well for that, but not when the view has a lot of components; things get lost is the noise.

A few fields... all it takes to make things messy...

To make things easier we added a hidden 'inspect' icon to each VW based component that is only rendered if 'WAAdmin developmentToolsEnabled' is true. It's toggled by a WAToolPlugin subclass icon. Here is how the same view looks with the inspect anchors visible (the title for each inspect icon is the display string of the objedt that would be inspected when clicked)...

Each 'widget' is contained in a div for absolute positioning. Inside this div we added the inspect render method...

renderInspectOn: html
Seaside.WAAdmin developmentToolsEnabled ifFalse: [^self].
html anchor
class: 'subcanvasInspector'; 
style: 'display: none; position: absolute; '; 
title: self displayString; 
onClick: (html jQuery ajax 
    script: [:s | s << (html jQuery ajax callback: [self inspect])]);
with: [html image style: 'width: 12px; height: 12px; '; url: RepWebFileLibrary / #inspect16Gif].

...and then we toggle the display with...

renderInspectWidgetsToggleOn: html
    html anchor 
      onClick: (html jQuery class: 'subcanvasInspector') toggle;
      onClick: (html jQuery class: 'subcanvasInspectorPlus') toggle;
      with: [
        html image 
  class: 'subcanvasInspectorPlus'; 
     url: Portal.RepWebFileLibrary / #inspectPlus24Gif.
html image 
  class: 'subcanvasInspectorPlus'; 
     style: 'display: none; '; 
  url: Portal.RepWebFileLibrary / #inspectMinus24Gif].


The other icons are for root component inspect, matching VW component inspect and a button to open the VW view (the deployed Seaside image has no VW domain view classes; these are being used during the application port).

With this setup we're able to port a VW application with 4497 window spec methods and keep our manual code work manageable.

Simple things should be simple. Complex things should be possible.


  1. Hi,
    I am new in Smalltalk and I was wondering if it supports a kind of reflection like Java/.Net do?
    I want to create a UI automation framework, which is why I have to communicate with a running Smalltalk UI to get its controls and states

  2. Reflection in Smalltalk comes naturally, since everything can be inspected. What I don't know is how that compares to Java / .Net. I'd suggest you post a question on Stack oveflow with a #smalltalk tag.