Setting and getting custom field values in CiviCRM hooks

CiviCRM isn't always the most predictable codebase. Recently I needed to get and set some custom field values in a hook I was writing. The hook's job was to calculate some custom field values and create some contact references when a contribution was created or updated. As always, dlobo was a huge help (he's the CiviCRM guru, find him in #civicrm on Freenode). Here's what I did to set a couple of custom fields in my _pre hook:


$custom_fields = array('foo' => 'custom_1', 'bar' => 'custom_2');
function modulename_civicrm_pre ($op, objectName, $objectId, &$objectRef) {
  if ($objectName != 'Contribution' || ($op != 'edit' && $op != 'create')) {
    return;
  }
  $contribution_id = $objectId;
  require_once 'CRM/Core/BAO/CustomValueTable.php';
  $my_foo = 'blah';
  $my_bar = 'baz';
  $set_params = array('entityID' => $contribution_id,
    $custom_fields['foo'] => $my_foo, $custom_fields['bar'] => $my_bar);
  CRM_Core_BAO_CustomValueTable::setValues($set_params);
}


And here's an example for retrieving some custom field values from the contact object in the same hook:


$custom_fields = array('contact_foo' => 'custom_3', 'contact_bar' => 'custom_4');
function modulename_civicrm_pre ($op, objectName, $objectId, &$objectRef) {
  if ($objectName != 'Contribution' || ($op != 'edit' && $op != 'create')) {
    return;
  }
  // set the field names to 1 that we want to get back
  $get_params = array('entityID' => $objectRef['contact_id'],
    $custom_fields['contact_foo'] => 1, $custom_fields['contact_bar'] => 1);
  require_once 'CRM/Core/BAO/CustomValueTable.php';
  $values = CRM_Core_BAO_CustomValueTable::getValues($get_params);
  $my_cfoo = $values[$custom_fields['contact_foo']];
  $my_cbar = $values[$custom_fields['contact_bar']];
}


So it's not ideal that you have to hard-code the custom field IDs; there should be a way to look them up (maybe there is). But it's not the worst thing in the world unless you're in the habit of destroying and recreating your custom fields from time to time. Probably you're not on a production system.