Re: Writing a beginners tutorial, some D2W questions on Webassistant and ERAtachment
Re: Writing a beginners tutorial, some D2W questions on Webassistant and ERAtachment
- Subject: Re: Writing a beginners tutorial, some D2W questions on Webassistant and ERAtachment
- From: David Chaney <email@hidden>
- Date: Sat, 19 Jan 2008 18:37:38 -0500
Johan,
Your proposed tutorial would have been extremely beneficial when I was
starting. Especialy since my first real project was a media content
site using D2W. Looking forward to seeing it when its done.
-david
On Jan 19, 2008, at 5:11 PM, Johan Henselmans <email@hidden> wrote:
On 19 jan 2008, at 22:01, Guido Neitzer wrote:
On 19.01.2008, at 13:47, Johan Henselmans wrote:
The application would be a shop, with a D2W backend for the
products (with ERAttachment for the product-pictures), fulfilment
(some kind of app that could run in an ipod touch) and some
statistics app that would make use of displaygroups and SVG.
The only thing I can say about that: Don't make beginners miserable
with D2W. To use D2W and to be able to customize an application to
your needs, you need a way more deep understanding of WebObjects
than a tutorial can provide.
I planned it to only use it for the backend application to add
products and product categories, and uploading pictures of the
products. That's it. just give a feel of DirectToWeb. Explain the
rule system, and how to customize a part. The other stuff would be
normal WebObjects stuff. Sorry if my phrasing was not precise. The
fulfillment and the statistics would make use of the other tools.
And personally I think that your tutorial is way overfilled with
stuff. Beginners can take only so much in a tutorial. If you don't
want to write a 600 page book, you will not be able to bring all
that stuff in, add diagrams and screenshots and explain everything
a beginner needs to know. And believe me: I know what I'm talking
about as I'm facing the same problem.
That tutorial is nearly finished, so I am starting with the
DirectToWeb part. On Leopard, the DirectToWeb Assistant does not
work.
If you really want to use D2W - stay away from that rule-breaking,
stupid assistant. Nobody will ever understand D2W in the necessary
way with seeing and writing actual rules. In my opinion that
assistant was a bad idea from the very beginning. And I do a lot of
D2W.
If you do a lot of D2W, you know the rulesystem, you'll have your
working examples and you'll know all the rules.
Now suppose you are a beginner. You are starting with a Direct2Web
app, which is supposed to be better than sliced bread, especially if
you are using Wonder. So he starts a WonderD2W Application in
WOLips, has an EOModel (a shop with a product, productcategory and
an n:m relation), and opens the app. He logs in, and adds some
products. It works. Nice. Than he adds a few product categories. Now
he wants to link the products and productcategories. Instead of
seeing the productcategories in a product he sees something called
com.webobjects.eocontrol._EOCheapCopyMutableArray[b2f057] , whatever
that may mean. A little disappointed, the developer tries to edit
the product. But where? By default he can only inspect them, and not
edit them. Why is that?
How is he going to change that? Very simple, the Direct2Web tutorial
says. You are too inexperienced. First learn all the intricacies.
Then, fire up the rule editor. Then add a rule: it is very simple,
just add
{
rules = (
{
author = 100;
class = "com.webobjects.directtoweb.Rule";
lhs = {
class = "com.webobjects.eocontrol.EOKeyValueQualifier";
key = task;
selectorName = isEqualTo;
value = list;
};
rhs = {
class = "com.webobjects.directtoweb.Assignment";
keyPath = isEntityEditable;
value = true;
};
}
);
}
See: it's that simple.
Now start reading again about all the tasks, of which you take one
then take one from the 17 right hand side classes and the 300
something right hand side keys, and some right hand side value. Very
Simple. You just have to know all the combinations, and you'll be
fine.
All the experienced Direct2Web developers have started this way.
His promise to whip up quick interface for the backend so he could
concentrate on the frontend can be thrown out of the window.
Oh well. On to Ruby On Rails, or sticking to PHP, or WebObjects
without D2W.
D2W has changed from a gentle introduction to webobjects and a quick
interfacebuilder to the steepest learning cliff...
(and no, Rule Editor is not an easy and quick tool if you're a
beginner and you don't want to shoot yourself in the foot)
Again: D2W is WAY OVER THE HEAD for a beginner to be happy with. It
is a very cool technology demonstration and it is an incredibly
powerful tool for WO developers who really understand WO but it is
also something where beginners will hit the wall with the first
customization they want to make.
cug
D2W without a proper assistant is. So how is one suppose to learn
D2W? How did you learn it?
I am not going to demonstrate all the intricacies of a d2w app: just
standard interface, a login routine, and a file-upload for a
picture. That's it, for now. It is meant to be a tutorial for
beginners, to give them a feeling of how it works, and give them a
feeling of one should go about. And then he/she can go on and find
out that for the really nifty stuff, he should get a training at the
Big Nerd Ranch ;-)
--
Real-World WebObjects class at the Big Nerd Ranch
March 2008, Frankfurt, Germany
http://www.bignerdranch.com/classes/webobjects.shtml
Regards,
Johan Henselmans
http://www.netsense.nl
Tel: +31-20-6267538
Fax: +31-20-6273852
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