Re: [Zope] ZClass subclassing a File

28 Jul 1999

      I'm going to put this on the list to see if anybody else has any ideas (I note 
that I just sent it back to Brian, not the list).

The short summary is I have a ZClass (MSFile) that is based on the File 
class provided with Zope. I add some properties to it. If I add an instance of 
this type, it acts just like a File type, not showing any of the properties 
that I have defined... 

Is this a bug, or am I not doing something right? I am using some code to 
import the file that I borrowed from a posting by Ross Reedstrom (Thanks!!) 
which I'm including below to see if that helps:

Bruce

----------------

 <dtml-comment>
Taken from e-mail from:

Ross J. Reedstrom, Ph.D., <reedstrm@rice.edu> 
NSBRI Research Scientist/Programmer
Computer and Information Technology Institute
Rice University, 6100 S. Main St.,  Houston, TX 77005
Date: Mon, 14 Jun 1999 10:29:25 -0500 (11:29 EDT)
on the Zope mailing list
</dtml-comment>

We need to set the 'id' to the filename if it's not set. The second line
strips the last component from the filename passed in the REQUEST.file
object, in a platform neutral hack. It fails if someone uses the
path seperator component from one platforn in the filename on another
platform. E.g. slashed dates in filenames on Macs. I stole it from cookId
in Image.py

<!--#/comment-->
<!--#unless REQUEST['id']-->
   <!--#call "REQUEST.set('filename',REQUEST['file'].filename)"-->
   <!--#call  "REQUEST.set('id',filename[_.max(
                        _.string.rfind(filename, '/'),
                        _.string.rfind(filename, '\\'),
                        _.string.rfind(filename, ':'),
                        )+1:])"-->
<!--#/unless-->

<H4>Sorry! That name exists, try again (use your browser's back button)</H4>
 fix this up
Would you like to:
New Name:
rename existing file
replace existing file
Upload with new name

<dtml-comment>
<!--#call "_.getitem(REQUEST['id']).manage_addProperty(
                   'addedby',REQUEST.get('AUTHENTICATED_USER'),
                   'string')"-->
</dtml-comment>

<FORM ACTION=<!--#var "URL1"--> METHOD="GET">
<H3>File Added</H3>
<INPUT type=submit value="OK">
</FORM>

<!--#/if-->

<!--#var standard_html_footer-->

---------------
...
...
...
I have a ZClass that has some properties, etc. I
want it to 
be a subclass of 
other ZClasses that I have defined, and the "File"
type 
provided by Zope.
What I want is a "File" that Zope recognizes, so
that I can 
load a file in, 
etc., but have the various properties/methods
available 
also... can this be 
done?
If I define my ZClass (say MSFile) as a subclass
of 
MSFileHolder (which 
provides some generic file/image handling that I
want to do), 
and a subclass 
of File, then it works as a File (I can never seem
to see the 
Properties 
pages, etc. that I set... if I open the
instantiation of the 
object in the 
management interface, I just see it as a "File"...
its as if 
the other stuff 
doesn't exist.
Am I way off base here?
No - you just need to create "views" for the
property sheets
that you want to be able to manipulate for your
MSFile instances.
I am pretty sure I have... (I'm not at home with the
machine right this minute).
...
A quick example: go to your MSFile ZClass and click
on "Property
Sheets", and create a property sheet called
"ExtraProperties" with
a few defined properties.
Next, click on the "Views" tab of your MSFile class
and add a new
"view" that points to that property sheet (type
"Extra" in the New
text box, and select
"propertysheets/ExtraProperties/manage" from
the select list and click the "Add" button.
OK, one difference I have (at least during my
testing), is that I had a PropertySheet View defined
for the superclass (MSFileHolder) of which MSFile is a
subclass (inherits from/based on - not defined on the
method's page of MSFileHolder, but rather is a
separate ZClass with MSFileHolder chosen during create
time).
In my other classes formed this way, I get a different
tab for each superclasses Properties page (just like I
want - that's great!), but for this "File" type, they
don't appear.
Any guesses?
Thanks,
Bruce
...
Now your MSFile instances should have an "Extra" tab
in their mgmt
interface, which will take you to the form for
managing the extra
properties on that instance.
Hope this helps!
Brian Lloyd        brian@digicool.com
Software Engineer  540.371.6909              
Digital Creations  http://www.digicool.com
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===
-- 
Bruce C. Dillahunty
Peachbush Enterprises
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-- 
Bruce C. Dillahunty
Peachbush Enterprises
bdillahu@mindspring.com