Add custom Contextual Links to Drupal node teaser pages

contextual_demo.php

<?php
/**
* Implements hook_permission().
*/
function YOUR_MODULE_permission() {
  return array(
    'YOUR MODULE article unpublish articles' => array(
      'title' => t('YOUR MODULE Article Unpublish'),
    ),
  );
}
/**
* Implements hook_menu().
*/
function YOUR_MODULE_menu() {
  $items = array();
  $items['node/%node/article/unpublish'] = array(
    'title' => 'Unpublish',
    'access callback' => '_YOUR_MODULE_article_unpublish_access_check',
    'access arguments' => array(1),
    'page callback' => '_YOUR_MODULE_article_unpublish',
    'page arguments' => array(1),
    'type' => MENU_LOCAL_TASK,
    'context' => MENU_CONTEXT_INLINE,
  );
  return $items;
}
/**
* Custom access check for node/%node/article/unpublish menu link.
*
* @param object $node Node object from menu argument.
* @return boolean TRUE if has access, FALSE otherwise.
*/
function _YOUR_MODULE_article_unpublish_access_check($node) {
  if ($node->type == 'article' && user_access('YOUR MODULE unpublish articles')) {
    return TRUE;
  }
  return FALSE;
}
/**
* Callback action to unpublish article.
*
* @param object $node Node object.
*/
function _YOUR_MODULE_article_unpublish($node) {
  node_object_prepare($node);
  $node->status = 0;
  node_save($node);
  watchdog('YOUR_MODULE', __FUNCTION__ . ' -- Unpublished article "%title" (NID: %nid).', array('%title' => $node->title, '%nid' => $node->nid), WATCHDOG_NOTICE);
  $destination = drupal_get_destination();
  $destination = isset($destination['destination']) ? $destination['destination'] : '<front>';
  drupal_goto($destination);
}
?>