public function GroupMembershipController::invoke in Group 7

Overridden to take care of saving membership roles.

If this functionality were placed in GroupMembershipController::save(), we'd find ourselves in a catch-22:

• On the one hand we need a membership id to save the roles to {group_membership_role}, requiring us to first save new GroupMembership entities before saving their roles.
• On the other hand, saving an entity causes the insert or update hooks to be invoked, leaving room for buggy behavior should one try to load the recently saved entity again (it gets removed from the cache upon being saved to the database).

To solve this without overriding EntityAPIController::save() and without having to fiddle with either module or hook weight, we place the code here because GroupMembershipController::invoke() is called right after the actual insert or update and we are sure to have a membership id already.

Overrides EntityAPIController::invoke

See also

EntityAPIController::save()

GroupMembershipController::save()

File

classes/group_membership.controller.inc, line 61

Defines the Entity API CRUD class for group memberships.

Class

GroupMembershipController

Controller for group membership entities.

Code

public function invoke($hook, $group_membership) {
  if ($hook == 'update' || $hook == 'insert') {

    // Below we take care of the 'roles' property that was set on the
    // GroupMembership; saving new roles to and removing revoked roles from
    // the database. For new GroupMembership entities, we can simply grant
    // all of the roles. For existing ones, we need to run some integrity
    // checks.
    if (!empty($group_membership->is_new)) {
      $grant = $group_membership->roles;
    }
    else {

      // Load the original entity to detect changes.
      $original = entity_load_unchanged('group_membership', $group_membership->mid);

      // Flag new roles for granting.
      $grant = array_diff($group_membership->roles, $original->roles);

      // Flag old roles for revoking.
      $revoke = array_diff($original->roles, $group_membership->roles);

      // Inform update hooks if any roles have changed. This is merely a
      // helper property so update hooks don't have to check again.
      $group_membership->roles_changed = $grant || $revoke;
    }

    // Grant the roles by inserting them into {group_membership_role}.
    if (!empty($grant)) {
      $query = db_insert('group_membership_role')
        ->fields(array(
        'mid',
        'role',
      ));
      foreach ($grant as $role) {
        $query
          ->values(array(
          'mid' => $group_membership->mid,
          'role' => $role,
        ));
      }
      $query
        ->execute();
    }

    // Revoke the roles by deleting them from {group_membership_role}.
    if (!empty($revoke)) {
      $query = db_delete('group_membership_role')
        ->condition('mid', $group_membership->mid);
      $query
        ->condition('role', $revoke, 'IN');
      $query
        ->execute();
    }
  }

  // Continue running the actual invoke logic.
  parent::invoke($hook, $group_membership);
}