Drupal settings snippet

drupal_stubs.inc

<?php

/**
 * @file
 * Stub code to fake drupal variable settings/getting functions
 */

$variables;

function variable_get($name, $default) {
  global $variables;
  return isset($variables[$name]) ? $variables[$name] : $default;
}

function variable_set($name, $value) {
  global $variables;
  $variables[$name] = $value;
}

example.api.inc

<?php

/**
 * @file
 *
 * For all of my modules, I create a class that represents the modules public API.
 *
 * Of course, I don't have to do this, this part isn't a normal Drupal convention, but its
 * a little nicer to me as the programmer, because the classes static functions act sort of
 * like a namespace, I get private functions and variables.  Also, the class frequently doubles
 * as an instantiable object (I'm breaking a serious OOP principle in doing that, I know -- each
 * class should have a single responsibility -- but PHP is a pain in the ass and so cut some corners
 * for convenience).
 *
 * Anyway, here I declare the concrete settings class and instantiate it.  In the end, I get to
 * do:
 *
 *   ExampleModule::$settings->config_option
 */

require_once('settings.inc');

class ExampleModuleSettings extends LingwoSettings {
  protected $base_name = 'example_module';

  /* taken from a real module:
   *   https://github.com/dsnopek/lingwo/blob/master/lingwo_entry/lingwo_entry.api.inc
   */
  private $defaults = array(
    'lookup_path' => 'dictionary',
    'node_title_munging' => array('language' => TRUE, 'pos' => TRUE),
    'redirect_node' => TRUE,
    'content_type' => 'lingwo_entry',
    'pos_allowed_values' => "noun|Noun\nadjective|Adjective\nverb|Verb\nadverb|Adverb\nother|Other",
    // except this one
    'automatic' => NULL,
  );

  /* made up code to show how automatic generation can happen */
  public function getDefault($name) {
    switch ($name) {
      case 'automatic':
        // the default is to depend on the value of a different variable
        return $this->lookup_path . "/automatic";

      default:
        return $this->defaults[$name];
    }
  }

  public function getNames() {
    return array_map(array($this, 'name'), array_keys($this->defaults));
  }

  public function isValid($name) {
    return array_key_exists($name, $this->defaults);
  }

  // singleton boilerplate
  private static $settings = NULL;
  public static function get() {
    if (is_null(self::$settings)) {
      self::$settings = new self();
    }
    return self::$settings;
  }
}

class ExampleModule {
  static public $settings;
}
ExampleModule::$settings = ExampleModuleSettings::get();

settings.inc

<?php

/**
 * @file
 * Helper code for managing module variables
 *
 * Taken directly from:
 *
 *    https://github.com/dsnopek/lingwo/blob/master/includes/settings.inc
 */

class LingwoSettings {
  protected $base_name = '';

  function __construct() {
    if (empty($this->base_name)) {
      throw new Exception('You must sub-class LingwoSettings and change $base_name!');
    }
  }

  public function __get($name) {
    $res = variable_get($this->name($name), NULL);
    if (is_null($res)) {
      $res = $this->getDefault($name);
    }
    return $res;
  }

  public function __set($name, $value) {
    variable_set($this->name($name), $value);
  }

  public function __isset($name) {
    return !is_null(variable_get($this->name($name), NULL));
  }

  public function __unset($name) {
    variable_del($this->name($name));
  }

  public function name($name) {
    if (!$this->isValid($name)) {
      throw new Exception('Invalid setting name: ' . $name);
    }
    return $this->base_name . '_' . $name;
  }

  public function getDefault($name) {
    return NULL;
  }

  public function isValid($name) {
    return TRUE;
  }
}

test.php

<?php
require_once('drupal_stubs.inc');
require_once('example.api.inc');

print 'lookup_path: ' . ExampleModule::$settings->lookup_path . "\n";
print 'automatic: ' . ExampleModule::$settings->automatic . "\n";
ExampleModule::$settings->lookup_path = 'zumma';
print 'lookup_path: ' . ExampleModule::$settings->lookup_path . "\n";
print 'automatic: ' . ExampleModule::$settings->automatic . "\n";
ExampleModule::$settings->automatic = 'zumma/foo';
print 'automatic: ' . ExampleModule::$settings->automatic . "\n";