change node access with drupal module

Question

I run drupal 6 and want to code this functionality: after the user filled out the formular he can click an extra button, which will make the form readonly for him.

I thought about an hidden_field and an extra button, which after the user clicked the extra button set the hidden_field to a true state. When I load the node and the hidden_field has the true state, I want to set all the fields in the node to readonly. (hook_access, node_access?!?)

puh.. hope this all is not too confusing (because even I am now a little confused...)

Answer 1

Firstly you won't be able to stop someone who has access to the database or the root user from seeing the data (at least not without some encryption).

In terms of normal site operation this isn't too hard to do. The two hooks you need to invoke are hook_node_grants() and hook_node_access_records(), there is quite a good example, which also pretty much does what you want in the question, here.

Put simply hook_node_access_records() returns a structure detailing relms and ids which can perform actions on it, and hook_node_grants() returns the relms and ids for a user. If there is a match between the two then access (read or write) is granted.

This gives you a lot of flexibility. One example would be that people could only read nodes created by other people with the same star sign. In hook_node_grants you would examine the user object to get the starsign and return $grants['starsign'] = 2

When a node is saved hook_node_access_records would have to check the star sign of the user who created it do something like:

 $grants = array();
 $grants[] = array(
  'realm' => 'starsign',
  'gid' => $account->starsign,
  'grant_view' => 1,
  'grant_update' => 0,
  'grant_delete' => 0,
  'priority' => 0,
);
return $grants

That way if the relm and group id match the user will be given read access.