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From Michael McGrady <michael.mcgr...@gmail.com>
Subject Re: Transparent and automatic AJAX support for CForms
Date Fri, 22 Apr 2005 04:53:29 GMT
I did not say what you say was "not true" Gallardo.  I should have
been more careful and I would have been had I known there were fragile
people out there who might be hurt.  As it was, I do not take myself
so seriously as some others do.  Anyway, I sure did not mean to
suggest that Cocoon was built by Frank Zammetti.  I thought I said:
"Thought I'd pass on to the Struts list the great success and
popularity Frank Zammetti's ideas are having on the Cocoon list."  Oh,
wait, I checked, and I did say that.  LOL  ///;-)

On 4/21/05, Antonio Gallardo <agallardo@agssa.net> wrote:
> On Jue, 21 de Abril de 2005, 3:07, Michael McGrady dijo:
> > Thought I'd pass on to the Struts list the great success and
> > popularity Frank Zammetti's ideas are having on the Cocoon list.
> 
> Hi Michael,
> 
> Unfortunately, I need to tell this just for the records:
> 
> In cocoon XmlHttpRequest was first saw in 9-Sept-2004 thanks to Ugo Cei:
> 
> $ svn log src/blocks/forms/samples/forms/xhr_carselector_template.xml
> 
> <snip/>
> ------------------------------------------------------------------------
> r43610 | ugo | 2004-09-09 10:36:28 -0500 (jue, 09 sep 2004) | 1 line
> 
> Carselector with XMLHTTPRequest sample
> ------------------------------------------------------------------------
> 
> I am not telling the article by Frank Zammetti's was not interesting. It
> was! The article helped me to understand AJAX. I am happy of that. But
> from this to tell that cocoon implemented AJAX based on the article is no
> true.
> 
> In my post I just related how I stepped. I just posted what I was trying
> to do. My answer takes almost 10 days since Sylvain original post, becaue
> I wanted to take my time to write a good answer for this great job,
> because while I was doing my small AJAX steps, Sylvain showed his own
> solution. He was faster than me for a lot of time. I don't know when I
> will finish that.
> 
> Kudos to Sylvain again! He is on my hero plate now! :-)
> 
> BTW, I expect to see this in 2.1.x soon! ;-)
> 
> Best Regards,
> 
> Antonio Gallardo.
> 
> >
> >
> > On 4/20/05, Antonio Gallardo <agallardo@agssa.net> wrote:
> >> Hi:
> >>
> >> Simply, wow, it is great! :-)
> >>
> >> I started to do something similar 4 days before you posted this
> >> solution!
> >>
> >> My main motivation was because repeater widget with comboboxes are very
> >> slow in 2.1.x. I saw a browser waiting around 2 minutes to show a form
> >> because the repeater data. The all form was +100kB! Of course, this was
> >> an
> >> unusable solution. Then we thought that a solution was break the form in
> >> more pieces, but this looked very ugly from a user POV.
> >>
> >> At that time, Tim Larson advised to look for an XmlHttpRequest solution
> >> integrated into cforms. The same day, I saw an struts related article in
> >> the theserverside:
> >>
> >> http://theserverside.com/news/thread.tss?thread_id=33056
> >>
> >> And I started to migrate this to cocoon in my free time. But with no
> >> major
> >> success. :-(
> >>
> >> I think, your solution is more elegant than what I tried to do. My idea
> >> was to generate client-side java script for every widget and send it to
> >> the browser, then the browser will react to the onfocus event of the
> >> widget and fill the list on demand. That way we don't need to fill all
> >> the
> >> lists at once and the page will load faster. I expected cocoon caching
> >> will help here.
> >>
> >> Also, given the fact that this solution was not needed on every combo, I
> >> thought to include an @ajax attribute in the "fi" namespace on the
> >> template as flag. Something similiar like I saw in the struts sample
> >> pointed above. Not at the form level as the committed solution.
> >>
> >> I have 2 questions:
> >>
> >> 1- Will this ajax implementation improve the combo loads in cforms?
> >> 2- Are you planning to merge it in 2.1.x? If not I will see the urge to
> >> move to 2.2 soon! :-D
> >>
> >> Thanks for this great improvement!
> >>
> >> Best Regards,
> >>
> >> Antonio Gallardo.
> >>
> >> On Jue, 14 de Abril de 2005, 8:19, Sylvain Wallez dijo:
> >> > Hi all,
> >> >
> >> > I've been thinking for a few weeks to add AJAX support to CForms. Ajax
> >> > is the current buzzword in the blogosphere since Google maps [1]
> >> started
> >> > and the folks at Adaptivepath found this name for the XmlHttpRequest +
> >> > JS + XML combo [2].
> >> >
> >> > At first this looked like a complex problem, requiring a special
> >> > controller and special pipelines on the server to answer ajax
> >> requests,
> >> > and "ajax-aware" implementations of widget styling (i.e. having a JS
> >> > client-side part to handle page update). Lots of code for the
> >> > infrastructure, and lots of browser-dependent code each time we want
> >> to
> >> > add a new styling.
> >> >
> >> > Then a few days ago I realized that we don't need that complexity.
> >> Form
> >> > widgets have all the information needed to inform the surrounding
> >> > environment if they need to be updated, and we can use this
> >> information
> >> > to do partial updates of the browser page.
> >> >
> >> > Two days hacking, most of which dedicated to writing client-side JS
> >> and
> >> > solving cross-browser compatibility problems and here we are: adding
> >> > ajax="true" on <ft:form-template> turns on the magic.
> >> >
> >> > This is still experimental though: it's only implemented with the
> >> > JXTemplate version of the CForms template language and requires a few
> >> > changes on repeater templates.
> >> >
> >> >                                 -- oOo --
> >> >
> >> > How does this work? The idea is, when answering and Ajax request, to
> >> > send back an XML document containing browser updates directives, that
> >> > will contain document fragments that will replace their existing
> >> > counterpart in the page, based on the element id.
> >> >
> >> > These directives are represented by "bu:replace" elements (bu =
> >> browser
> >> > update) holding the id of the page element that needs to be replaced.
> >> > This is a very generic mechanism that at this point isn't specifically
> >> > related to CForms. This could for example probably be used by the
> >> portal
> >> > to update coplet contents.
> >> >
> >> > Now CForms. When a widget is updated in some way (new value, selection
> >> > list changed, repeater row added or moved, union case updated, etc),
> >> it
> >> > registers itself in a list of updated widgets in the Form object.
> >> >
> >> > The template works as usual unless there is a special "cocoon-ajax"
> >> > parameter, indicating an ajax request from the browser. In that case,
> >> > widgets that have changed are enclosed in a "bu:replace" element,
> >> > holding the widget id.
> >> >
> >> > This mix of template structure, and widget instances surrounded by
> >> > bu:replace elements goes to styling, which replaces widget instances
> >> by
> >> > their HTML styling, still in the bu:replace elements.
> >> >
> >> > A new "browser-update" transformer flattens the "bu:replace" elements,
> >> > i.e it removes all surrounding markup produced by the template. We now
> >> > have a list of partial page updates that are serialized as XML.
> >> >
> >> > On the brower, the update directives are "played" and the page is
> >> > updated. And that's all.
> >> >
> >> >                                 -- oOo --
> >> >
> >> > Any widget, any styling can now be managed this way. The only -- but
> >> > important -- constraint is that the html produced for a widget
> >> instance
> >> > need to have the same id attribute as the widget.
> >> >
> >> > This constraint is satisfied for all field stylings (I updated the
> >> > stylesheets), but not always for containers (repeaters, structs, etc).
> >> >
> >> > About repeater, this requires a change in the template language, to
> >> > separate the repeater itself from the iteration on its rows. So rather
> >> > than:
> >> >   <table>
> >> >     <!-- header -->
> >> >     <ft:repeater-widget id="myrepeater">
> >> >         <!-- row -->
> >> >     </ft:repeater-widget>
> >> >   </table>
> >> >
> >> > we now have to write:
> >> >   <ft:repeater id="myrepeater">
> >> >     <table>
> >> >       <!-- header -->
> >> >       <ft:repeater-rows>
> >> >         <!-- row -->
> >> >       </ft:repeater-rows>
> >> >     </table>
> >> >   </ft:repeater>
> >> >
> >> > I have turned on ajax mode on the following samples:
> >> > - http://localhost:8888/forms-samples/carselector
> >> > - http://localhost:8888/forms-samples/do-dynaRepeater.flow
> >> > - http://localhost:8888/forms-samples/do-datasourceChooser.flow
> >> > - http://localhost:8888/forms-samples/do-taskTree.flow
> >> >
> >> >                                 -- oOo --
> >> >
> >> > Next steps are better handling of container widgets and finer-grained
> >> > browser update for some often-used stylings such as dropdowns and
> >> inputs.
> >> >
> >> > Now that Cocoon has Spring and Ajax support, we really should post an
> >> > article on TSS ;-)
> >> >
> >> > Enjoy,
> >> > Sylvain
> >> >
> >> > [1] http://maps.google.com/
> >> > [2]
> >> http://www.adaptivepath.com/publications/essays/archives/000385.php
> >> >
> >> > --
> >> > Sylvain Wallez                        Anyware Technologies
> >> > http://apache.org/~sylvain            http://anyware-tech.com
> >> > Apache Software Foundation Member     Research & Technology Director
> >> >
> >>
> >>
> >
> 
>

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