I've struggled with doing this, too. I updated some of the CCK developer documentation on drupal.org to Drupal 6 as I went along figuring things out, but obviously only hit minor bits and pieces.
You can look at the source for the moodle module (http://drupal.org/project/moodle) in the moodle.cckfield.inc file for the development code I was last working on to do this a few months ago. It is a very hacked up copy of the computed field code, if I remember correctly. Please, please! -- if anyone figures out any pieces of how CCK works in Drupal 6 -- add documentation below the top-level page at http://drupal.org/node/101742 . The only 2 people who know how it really works are the maintainers, and they're busy working on Drupal 7. ..chris On Mon, Jun 22, 2009 at 12:05 PM, David Hautbois<[email protected]> wrote: > I've done this using the CCK Computed Field. > > But I would like to learn more about CCK fields development. > And my company give some time to do this... > > Thanks. > > David > > Brian Vuyk wrote: >> >> Is it something that could be done using a CCK Computed Field? It allows >> the field to be populated using PHP, and had the contents of the other >> fields available to it. >> >> Might be a little simpler than doing something in a module. Unless, of >> course, you don't want it's function accessible from the frontend. >> >> Brian >> >> On 06/22/2009 12:44 PM, David Hautbois wrote: >>> >>> Hi >>> I'm developping a custom CCK field for Drupal 6. >>> I'm don't want the user set the value himself. So, this field has no >>> widget. >>> >>> I'm looking for how to set the value when the node is saved. (the value >>> is set when the node is created et not updated) >>> In hook_field, I tried to use 'presave' ou 'validate' for $op, but I've >>> some problems to work with it : >>> - 'presave' seems to be called when the node is displayed... >>> - when the node is created, the field has no value ($items[0]['value'] >>> does not exists) >>> - ... >>> >>> I 've look in some others CCK fields, but no one work like this. >>> >>> I copied the text_field CCK field, renamed all 'text_field' references, >>> simplified it and removed the widget. >>> >>> Can someone help me or point me to a good web page ? (not the CCK dev >>> documentation !, I read it many times!) >>> >>> Thanks. >>> >>> David >> >> >> -- >> *Brian Vuyk* >> Web Design & Development >> T: 613-534-2916 >> Skype: brianvuyk >> [email protected] | http://www.brianvuyk.com >
