[Bese-devel] say a warm welcome to ucw+, event-based ucw implementing ajax.

[Evrim ULU]

Hi,

I'm very proud to announce ucw+ implementing ajax. 

* What is ucw+?

This is an add-on to ucw_dev repository implementing event-based web
programming. It makes easier to write web applications and provides a
desktop like programming style to web applications.

* What is event-based/event-driven programming?

Event based programming is the idea that decouples controller from the
view. Current <ucw: tags couples view(html) with the controller
(actions) and makes html output unreadable, unmaintanable. So,
event-based programming allows us to define controller seperately and
blesses us with the MVC pattern.

* What about ajax?

ucw+ implements ajax very cleanly and elegantly discarding <ucw: tags.
As said, It encourages implementing controller seperately via
(render-javascript ajax-component) method of ajax-component.  The rule
is, provide all necessary actions in the controller and provide only
permalinks in the render method (i.e. (<:a :href (href "show-user.ucw"
:id *id*)) so that search engines can crawl. This cleans the view(html)
which can be observed in the tests.

Also, as a bonus, every ajax-component has a render-css method which
provides component specific style. Via this component specific style
option, It enables us to produce "style customizable web applications"
which is a unique feature afaik.

Ucw+ enables us to connect any DOM events of any html element, and
resulting applications will be more interactive and more responsive.

Finally, i've added some dojo fade-in/out special effects.

* Does ucw+ interfere with ucw_dev?

No. ucw+ does not change/alter anything that currently ucw_dev has.
This's a very big advantage for those who wants to use vanilla ucw_dev. 
I'll be happy to merge ucw+ with ucw_dev if everybody likes the idea.

* Why not ucw_ajax?

Current ucw_ajax has lots of ucw_dev refactoring which i personaly has
strong opposing ideas. Let me summarize them:

- Action refractoring is not needed to provide ajax actions and
complicates action handling a lot. I didn't like the
raw-request-handling macros since it breaks the usual request-response
loop. It's very hard to debug and catch the cycle for me:(
- with-action-args macro is nearly the same as in lol code that Drew
Crampsie owns. It is very long, hairy and unmaintainable imo.
- Coupling controller and view makes "back-button" support impossible to
implement since frames are going to expire and ucw will tell you "No
Frame/Action found". This is a very big design handicap since average
web users will use "backbutton" a lot.  I'vent implemented back-button
support yet since i couldn't able to run backbutton support of
dojo.io.bind but the rest is trivial, just go to previous frame and call
render method of the current-window.
- Disabling frame generation at action handling is something that
disobeys the nature of the ucw and i really didn't want to break
session/frame/action chain.
- Current ucw_ajax supports only onclick event which is not enough to
implement an interactive web application.  To hook another type of
event, users have to implement additional js stack and modify <ucw: tags
which is a hard task for average user to do.
- ucw+ js stack implementation is much smaller and readble than current
ucw_ajax.
- afaik, ucw_ajax does not support IE6. (Attila, please correct me if
i'm wrong, dojo.dom.textContent fails in IE6)

* Which browsers it supports?

I've tested ucw+ with Mozilla, Firefox, Internet Explorer 6 and Opera.
On safari, ucw+ gives [Dom Exception 8]. Unfortunately, i don't own a
Mac so fixes are welcome.

* Enough, show me it in action.

Aycan Irican is currently working on a project using ucw+, until it's
done one may see tests at:
http://coretal.core.gen.tr:8080/ucw-plus/index.core

* How to use it?

Just load ucw+ asdf system i.e. (asdf:oos 'asdf:load-op :ucw+) to get
ucw+ code go into ucw package. It does not defines any packages in order
not to complicate the situation more. To see the tests running, create a
*default-server* and load ucw+.test system i.e. (asdf:oos 'asdf:load-op
:ucw+.test) and go to the url http://localhost/ucw-plus/index.core. If
you don't have a *default-server* running, it'll try to create a
mod-lisp backended server which is what i'm using.

I've provided the dojo profile that i use as c0r3.profile.js for users
who wants to build dojo by their own. If not, just set *dojo-url* to
"http://coretal.core.gen.tr/dojo/dojo.js" and use it over the net.

*Currently*, as 07.07.2006, parenscript is broken. So, please unpull the
patches belonging to that date.  I'm sure Attila Lendvai is going to fix
it soon.

* Where is the code?
To grab a fresh copy, one may execute: darcs get
http://common-lisp.net/project/core-services/repos/ucw+

Have a nice day.
Evrim.