Writing conditions

Conditions are the least complex Rules extension. To provide new conditions to Rules, you need two things – a function returning TRUE or FALSE, and an implementation of hook_rules_condition_info() to tell Rules about your condition. The info hook should return an array on the following form:

$conditions = array('mymodule_rules_condition_check_a_node_value' => array(
  'group' => t('My module'),
  'label' => t('My condition'),
  'parameter' => array(
    'var_1' => array(
    'type' => 'node',
    'label' => t('Condition parameter 1 (node)'),
  ),
  'var_2' => array(
    'type' => 'text',
    'label' => t('Condition parameter 2 (text)'),
  ),),
);),
return $conditions;

The outermost key in the array above is by default the name of the callback function for the condition – more than one condition can be declared by adding more keys. As usual, make sure to prefix your functions with your module name. Especially note the property parameter, used for telling Rules which type of data the condition uses as input. There can be any number of parameters – including none – for a condition callback. These are used by the callback function, which returns TRUE or FALSE:

function mymodule_rules_condition_check_a_ node_value($var_1, $var_2) {
// Condition logic goes here...
  return $result;
}