Drupal : add filter short code

filter_example.module

<?php
/**
 * filter_example.info
 * name = Filter example
 * description = An example module showing how to define a custom filter.
 * package = Example modules
 * core = 7.x
 * files[] = filter_example.test
 * 
 * ; Information added by  packaging script on 2013-11-04
 * version = "7.x-1.x-dev"
 * core = "7.x"
 * project = "examples"
 * datestamp = "1383601761"
 * 
 */

/**
 * @file
 * Module file for filter_example.
 *
 * 1-visit : http://localhost/drupal-7.24/admin/config/content/formats
 * 2- set checkbox : Foo Filter (example) , Time Tag (example)
 * 3- you can configure foo replacment word at the bottom input box
 * 4- go to any article enable full html and write foo or  <time />
 */

/**
 * Implements hook_menu().
 */
function filter_example_menu() {
  $items['examples/filter_example'] = array(
    'title' => 'Filter Example',
    'page callback' => '_filter_example_information',
    'access callback' => TRUE,
  );
  return $items;
}

/**
 * Implements hook_help().
 */
function filter_example_help($path, $arg) {
  switch ($path) {
    case 'admin/help#filter_example':
      return _filter_example_information();
  }
}

/**
 * Simply returns a little bit of information about the example.
 */
function _filter_example_information() {
  return t("<p>This example provides two filters.</p><p>Foo Filter replaces
    'foo' with a configurable replacement.</p><p>Time Tag replaces the string
    '&lt;time /&gt;' with the current time.</p><p>To use these filters, go to !link and
    configure an input format, or create a new one.</p>",
    array('!link' => l("admin/config/content/formats", "admin/config/content/formats"))
  );
}

/**
 * Implements hook_filter_info().
 *
 * Here we define the different filters provided by the module. For this example,
 * time_filter is a very static and simple replacement, but it requires some
 * preparation of the string because of the special html tags < and >. The
 * foo_filter is more complex, including its own settings and inline tips.
 */
function filter_example_filter_info() {
  $filters['filter_foo'] = array(
    'title' => t('Foo Filter (example)'),
    'description' => t('Every instance of "foo" in the input text will be replaced with a preconfigured replacement.'),
    'process callback'  => '_filter_example_filter_foo_process',
    'default settings' => array(
      'filter_example_foo' => 'bar',
    ),
    'settings callback' => '_filter_example_filter_foo_settings',
    //under Text format select in create article when select full html tips is shown
    'tips callback' => '_filter_example_filter_foo_tips',
  );
  $filters['filter_time'] = array(
    'title' => t('Time Tag (example)'),
    'description' => t('Every instance of the special &lt;time /&gt; tag will be replaced with the current date and time in the user\'s specified time zone.'),
    'prepare callback' => '_filter_example_filter_time_prepare',
    'process callback' => '_filter_example_filter_time_process',
    'tips callback' => '_filter_example_filter_time_tips',
  );
  return $filters;
}

/*
 * Foo filter
 *
 * Drupal has several text formats (they are not filters), and in our example
 * the foo replacement can be configured for each one of them, so the module
 * includes a settings callback, with options to configure those replacements.
 * Also, a Tips callback will help showing the current replacement
 * for the content type being edited.
 */

/**
 * Settings callback for foo filter
 *
 * Make use of $format to have different replacements for every input format.
 * Since we allow the administrator to define the string that gets substituted
 * when "foo" is encountered, we need to provide an interface for this kind of
 * customization. The object format is also an argument of the callback.
 *
 * The settings defined in this form are stored in database by the filter
 * module, and they will be available in the $filter argument.
 */
function _filter_example_filter_foo_settings($form, $form_state, $filter, $format, $defaults) {
  $settings['filter_example_foo'] = array(
    '#type' => 'textfield',
    '#title' => t('Substitution string'),
    '#default_value' => isset($filter->settings['filter_example_foo']) ? $filter->settings['filter_example_foo'] : $defaults['filter_example_foo'],
    '#description' => t('The string to substitute for "foo" everywhere in the text.')
  );
  return $settings;
}

/**
 * Foo filter process callback.
 *
 * The actual filtering is performed here. The supplied text should be returned,
 * once any necessary substitutions have taken place. The example just replaces
 * foo with our custom defined string in the settings page.
 */
function _filter_example_filter_foo_process($text, $filter, $format) {
  $replacement = isset($filter->settings['filter_example_foo']) ? $filter->settings['filter_example_foo'] : 'bar';
  return str_replace('foo', $replacement, $text);
}


/**
 * Filter tips callback for foo filter.
 *
 * The tips callback allows filters to provide help text to users during the
 * content editing process. Short tips are provided on the content editing
 * screen, while long tips are provided on a separate linked page. Short tips
 * are optional, but long tips are highly recommended.
 */
function _filter_example_filter_foo_tips($filter, $format, $long = FALSE) {
  $replacement = isset($filter->settings['filter_example_foo']) ? $filter->settings['filter_example_foo'] : 'bar';
  if (!$long) {
    // This string will be shown in the content add/edit form
    return t('<em>foo</em> replaced with %replacement.', array('%replacement' => $replacement));
  }
  else {
    //this show when click on the "More information about text formats" link behind "Text format" select in create article view
    return t('Every instance of "foo" in the input text will be replaced with a configurable value. You can configure this value and put whatever you want there. The replacement value is "%replacement".', array('%replacement' => $replacement));
  }
}

/**
 * Time filter prepare callback.
 *
 * We'll use [filter-example-time] as a replacement for the time tag.
 * Note that in a more complicated filter a closing tag may also be
 * required. For more information, see "Temporary placeholders and
 * delimiters" at http://drupal.org/node/209715.
 */
function _filter_example_filter_time_prepare($text, $filter) {
  return preg_replace('!<time ?/>!', '[filter-example-time]', $text);
}

/**
 * Time filter process callback.
 *
 * Now, in the "process" step, we'll search for our escaped time tags and
 * do the real filtering: replace the xml tag with the date.
 */
function _filter_example_filter_time_process($text, $filter) {
  return str_replace('[filter-example-time]', '<em>' . format_date(time()) . '</em>', $text);
}


/**
 * Filter tips callback for time filter.
 *
 * The tips callback allows filters to provide help text to users during the
 * content editing process. Short tips are provided on the content editing
 * screen, while long tips are provided on a separate linked page. Short tips
 * are optional, but long tips are highly recommended.
 */
function _filter_example_filter_time_tips($filter, $format, $long = FALSE) {
  return t('<em>&lt;time /&gt;</em> is replaced with the current time.');
}

/**
 * @} End of "defgroup filter_example".
 */