[Zope] Help wanted on Zope ZClasses/DTML please.

[Bowyer, Alex]

Hi,

I have only just started developing in Zope over this last week. I like it a
lot, but I am having problems finding solutions to some of my more specific
problems in the various zope documentations. I am hoping that if I describe
my problems, one of you more-experienced Zope users out there will be able
to help me.

First some background:

Basically I have written a news page which allows you to add/edit/delete
articles from it. It is similar in some ways to the Zope HowTo "Build a
searchable job board". It revolves around two classes:

(UA stands for Update Australia, the name of the news page)

UAArticle : A single article, to be included on the page.
---------
Properties:
 article_title,article_author and article_text (self-explanatory)
DTML Methods:
 index_html - renders the data from the three properties into HTML ready for
inclusion in the news page
 edit - a page with a form to allow you to modify the content, submits to
"update"
 update - processes the form results from "edit", updates the properties and
redirects

UAPage : the page itself, inherits from ObjectManager and has Add UAArticle
permission defined. Each instance contains 0 or more UAArticles.
------
Properties:
 issue_date, issue_number, intro_text (self-explanatory)
Methods:
 index_html - renders the page to HTML, both from these properties and by
calling the index_html of each subcomponent UAArticle.
 edit - a set of forms for modifications to edit the above three properties
and add a new article, or select an article to edit or delete.
 update - processes updates to the UAPage properties that have been made on
the edit page.
 edit_article - once an article is selected and the Edit button is clicked,
this finds the article, calls the edit method and gives feedback.
 add_article - a form to create a new article and add it to the UAPage.
 create_article - processes the data from the add_article form and actually
makes the object and adds it.
 delete_article - once an article is selected and the Delete button is
clicked, this finds the article, deletes it and gives feedback.

Now to the problems I have got:

1) I cannot get my delete_article method to work. I figured I need to use
manage_delObjects, but I can't find a working example to copy from and my
code doesn't seem to do anything. The following code gets called by a form
with a field called article_to_delete which is the title of the article we
want to delete:

<dtml-var standard_html_header>
<!-- set a flag to NULL, change it if found -->
<dtml-call "REQUEST.set('id_to_delete','NULL')">
<!-- get the title of the article to delete -->
<dtml-let the_match="REQUEST['article_to_delete']">
<!-- search for the article -->
<dtml-in objectValues>
  <dtml-with sequence-item><dtml-with propertysheets><dtml-with
UAArticleClassPropertySheet>
  <dtml-if expr="article_title==the_match">
    <dtml-call "REQUEST.set('id_to_delete',title_or_id)">
    <!-- found it, update the flag -->
  </dtml-if>
  </dtml-with></dtml-with></dtml-with>
</dtml-in>
<!-- test the flag to see if found -->
<dtml-if expr="REQUEST['id_to_delete']=='NULL'">
  <!-- not found -->
  <h2>Article not found</h2>
  <P>Could not find the article to delete.</P><P><A HREF=edit>Return to
maintenance page</A></P>
<dtml-else>
  <!-- found -->
  <dtml-let the_id="REQUEST['id_to_delete']">
  <!-- do the deletion - this is the bit that doesn't work -->
  <dtml-call "manage_delObjects('the_id')">
  <h2>Article deleted</h2>
  <P>Deleted article '&dtml-the_match;' (id='&dtml-the_id;').</P><P><A
HREF=edit>Return to maintenance page</A></P>
  </dtml-let>
</dtml-if>
</dtml-let>
<dtml-var standard_html_footer>

This gets an error that the_id does not exist. But I can't put <dtml-call
"manage_delObjects('REQUEST['id_to_delete']')"> because that is quotes
within quotes within quotes. I also tried  <dtml-with the_id><dtml-call
"manage_delObjects()"></dtml-with> but that doesn't seem to do anything.
What is the correct way to use manage_delObjects?

2) I need to be able to make a "Back" button on the UAArticle's edit page
that will return to the UAPage's edit page. The problem is that if I use <A
HREF=edit> it just goes to the edit page of the object, because our current
location is within the UAArticle not the UAPage. Is there a way to get the
name of an object's parent (or its own name for that matter) and use it to
construct a URL?

3) When redirecting or linking to a page I have already visited, how can I
force a refresh? I tried the JavaScript window.location.reload(true) but I
think that is only supported by Netscape. It didn't work in IE5 for me
anyway.

4) What is the best way to handle security with ZClasses. In my example I
want the index_html pages to be public but everything else to require a
password. I managed to require a password for a particular instance of the
UAPage, but that affects both the index_html and the edit pages.

Thanks very much for taking the time to read this - I hope someone can put
me out of my misery! - I have been fiddling around with the code for ages,
getting nowhere fast, and the documentation wasn't much help in these areas.
It just seems to cover the basics of ZClasses.

Regards,

Alex

==================================
Alex Bowyer
IT Contractor, Logica Australasia
Tel    : +61 2 9202 8130
Fax    : +61 2 9922 7466
E-mail : bowyera@logica.com
WWW    : http://www.logica.com.au/
==================================