[Zope] Zclass subclassing Image - how to manage uploads?

[Marius Kjeldahl]

I've seen numerous postings about this, but so far I have been
unsuccessful in successfully subclassing the Image with my own ZClass
(called VProduct for this case). Here's what I have managed to do:

* Create my new VProduct ZClass with Image as a base class
* Add a couple of new simple (string) properties to VProduct
* Modify the VProduct_add and VProduct_addForm methods so that my new
properties gets asked for and filled in (and using the system clock to
generate  unique id's)

This seem to work great, and I can move about in the Zope filesystem and
add instances of my VProduct class as I want to.

I have not been able to successfully integrate the file upload feature.
What I have done is:

* Add an input file <input type=file name=file> in the addForm method
* Putting a file name in this field and pressing submit button

From here I am not quite sure what to do with the image, but from
browsing earlier postings about this, it seems to have something to do
with calling manage_upload one way or the other.

In the VProduct_add method, I have the following special code:

<dtml-call "REQUEST.set('ts', ZopeTime ())">
<dtml-call "REQUEST.set('id', _.str(_.int('ts')))">

The above code generates a unique id for my VProduct instances, and this
works fine.

Inside the automatically generated:

<dtml-with "VProduct.createInObjectManager(REQUEST['id'], REQUEST)">

further down in the VProduct_add method I have the following stuff:

  <dtml-call "propertysheets.Basic.mange_editProperties (REQUEST)">

that code should take care of modifying the properties of my VProduct
instance (and assumes I guess that the input field names match the
property names). This seams to work great.

Right before the "propertysheets..." line I have tried adding the
following:

  <dtml-call "manage_upload(REQUEST['file'])"> 

It does not generate an error. But it does not seem to manage the upload
part either, since my VProduct instance gets the content_type
"text/plain" (instead of image/jpeg which is the right type for the jpeg
file I try to upload). And when I try to "view" the VProduct instance, I
get a simple <img src="91231912" alt="sometext"> tag which displays like
a missing image in a web browser (no wonder since the content_type is
wrong). I have tried manually setting the content_type to "image/jpeg",
but the image still does not display correctly. My guess is that the
image never got uploaded.

Any ideas on how to handle the upload properly? I've done some 30
searches through the list archive, without any clear answers to how the
image uploads are handled (or should be handled). I've looked carefully
through the howto's but have not found anything.

Any help would be appreciated.

Marius Kjeldahl