Module development and code questions

Say that I want to create user groups where each class is its own user group. And I each want them to view their own data but not somebody elses. How would I accomplish that? I want each class to read its own announcements, its own forum data, etc etc. Is there something I can do with taxonomy to make that happen? I don't really want to have to build custom modules for everything or hack a bunch of modules to get this accomplished.

Thanks!

Jay

I have a page on my site where I show nodes of a certain category and right now they're in order of date. Is there a way to make them in order of their weight and add a weight (like with blocks) to each node? Does that make sense?

I already have a form that I was using to suscribe to a newsletter (using webform module) and I read in the simplenews features that you can suscribe
"to the newsletters is managed through blocks, and/or a subscription form, and/or a custom page" but I can't find how to connect them... :-\

Is there a setting or a way to add an edit field for "Full Name" when suscribing to the newsletter?.. OR how can I use the webform I already have?

Thanks!

Just curious are there any functions or variables to get the Drupal's version in place? This could be very useful when people try to develop a version-independent module.

Has anyone been able to, or will we soon be able to implement the stock and stock.api module into 4.7?

I am using Drupal 4.7b4 and am having a problem with hook_nodeapi('validate'...) that I am really hoping someone can shed some light on.

I am using hook_nodeapi and hook_form_alter to add an image upload function to some of my existing nodetypes. My code works fine except if I preview a node before submitting it.

The problem is that hook_nodeapi('validate'...) is being called multiple times. My code looks as follows:

case 'validate':
if ($file = file_check_upload('nodeimage_upload'))
{
   $file = file_save_upload('_upload', _get_filename($file->filename), FILE_EXISTS_RENAME);
   ...
}

The first time $op='validate' is called, everything works fine, except that file_save_upload() removes the temporary file created when the node is submitted.
What this means is that for every subsequent call of hook_nodeapi('validate'...), I get the following error:
"The selected file could not be copied, because no file by that name exists. Please check that you supplied the correct filename."

I have read the forums and everthing else that I can find in the docs and I still cant find out how to fix my problem. Very similar code in 4.6 worked fine. Is this a bug, a new feature introduced in 4.7 or simply a huge gap in my understanding?

The sequence of nodeapi calls I am getting is as follows:

• load
• prepare
• validate
• view
• validate