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 <[EMAIL PROTECTED]> 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 >> > >> >> >
