ERPrototaculous

Introduction

ERPrototaculous was developed to provide the ajax functionality in ERDivaLook.

What is ERPrototaculous?

Features include:

• 'Organic' support for Prototype and Scriptaculous in WebObjects.
  • Light-weight dynamic elements to support Prototype
  • No custom patches to Prototype
  • Sans extensions to Prototype
• Use of Unobtrusive Javascript.
• Pseudo-stateless ajax responses
• A set of widgets in the Prototype + Scriptaculous family.

Unobtrusive Javascript in ERPrototaculous

Unobtrusive javascript is used in contrast to on-demand style of ajax programming.
By including Javascript as well as CSS globally in the page wrapper, CSS and Javascript don't have to load inside each and every ajax requests.
This keeps the ajax responses compact and simple.

The result is faster and more reliable ajax in WebObjects.

Prototype WebObjects Elements

Ajax.Updater and Ajax.Request have been implemented as WebObjects elements.

Ajax.Updater

Support for Prototype's Ajax.Updater is in the form of three elements:

• AjaxUpdaterLink
• AjaxUpdaterButton
• AjaxUpdaterForm (with onsubmit for ajax form submission)

These components will update any container on the page:

Ajax.Request

Prototype's Ajax.Request is in the form of:

• AjaxRequestLink
• AjaxRequestButton

These are used for strictly background ajax communication:

Prototype + Scriptaculous Widgets

• Accordion
• LightWindow
• ModalBox
• CalendarDateSelect
• FileUpload

Support for these widgets have been similarly implemented as button and link variants, depending whether it is used inside a form or not.

Ajax Forms in ERPrototaculous

Differences from using forms in WebObjects. i.e WOForm:

1. All ajax form controls must be named. This includes text fields, selects and buttons.
   (WebObjects dynamically assigned names are not compatible with ERPrototaculous).
2. All ajax forms in an ERPrototaculous app need to be instances of AjaxUpdaterForm.
3. Ajax form submit buttons can be a:
   • Static <button>.
   • WOSubmitButton (if the result is to update whole page/app).
   • AjaxUpdaterButton (to update a container). Or
   • AjaxRequestButton (for a background ajax request).

So forms are different in Ajax.framework and ERPrototaculous.

In ERPrototaculous you may still have typical WebObjects forms (i.e WOForm) as well as use ajax forms (i.e AjaxUpdaterForm).
They behave differently in that an AjaxUpdaterForm will update the contents of a container as opposed to the entire page.

Ajax Response Handling in ERPrototaculous

One notable difference between the ERPrototaculous and Ajax frameworks is in the way they handle ajax responses.
In ERPrototaculous, updates and actions break with The WebObjects Way by being pseudo-stateless.

In a typical WebObjects application, when a user navigates to the previous page using the browser back button and subsequently clicks on a link in on that page, WebObjects needs to remember how to handle that action and to return the correct page. This is no longer necessary for ajax.

A user never travels backwards or forwards through the ajax application history.
(i.e there is no forward/back buttons for ajax requests - just as there aren't forward/back buttons on desktop apps).

So for ajax, the current state of the page fragment component is all that is necessary.

Ajax Actions in ERPrototaculous

Typically, in a WebObjects application, an action would return the contents of the entire page.

Ajax responses are mostly page fragments or just part of a page.
So you should make sure the actions in ERPrototaculous (or AjaxUpdaterButton and AjaxRequestButton) return the proper page fragment as opposed to the entire page.
This breaks with WO-tradition (again), so this is where you need to be careful.

To assist with page fragments inside forms, you can make your ajax action responses a subclass of WXPageFragment (a utility to handle the forms processing between Prototype and WebObjects).

Update Containers in ERPrototaculous

Perhaps the only real similarity to Ajax.framework is the ajax update container.
WXGenericContainer is the ERPrototaculous update container.
It is similar to an AjaxUpdateContainer when it has the binding ajax = true, otherwise it's pretty much like WOGenericContainer.

It has been implemented as a utility or convenience for Prototype's Ajax.Updater.
That is it can be used to update from a DOM event like popup onchange, or from a Prototype callback like onComplete, etc.

Compatibility

ERPrototaculous can not be used with WebObjects 5.3 as it is dependent on the hooks for ajax added to WebObjects with version 5.4.