Drupal 7 Module Development

Chapter 9
When hook_node_access_records() fires, it passes a single parameter, the $node
object being acted upon. Our module must respond based on the information in the
$node object or be able to derive its rules from that information.
This last statement may seem obvious, but bears repeating. If
your business rules rely on special information not found in the
default $node object, it is your responsibility to add that data
using hook_node_load(). We will look at this in more detail
later in this chapter.
For Role Access, we need to know the roles assigned to the user who authored
the node.
/**
* Implement hook_node_access_records().
*
* We want to store a row for each role assigned
* to the author of the content.
*
*/
function role_access_node_access_records($node) {
// First get the user record. Note that we avoid using $user here,
// since that is the global $user object.
$account = user_load($node->uid);
// Now, get the roles array from the $account object.
$roles = array_keys($account->roles);
Here we use the Drupal API to grab the roles assigned to the node author. The use of
array_keys() in the last line means that we will be given a simple array of role ids.
These role ids will be used as the grant ids that we store in the {node_access} table.
A typical $roles result will look like this if we var_dump() its value:
array(2) {
[0]=> int(2)
[1]=> int(4)
}
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