Is there a rest api for the drupal admin interface (e.g. for clearing the cache)

I'm using cloud based continuous integration to deploy my theme to my drupal site, and I would like to be able to automate the clearing of the cache after the theme files are copied in place.

Is there a way of doing this remotely?

I'm thinking it would be great if there was a rest api to do things like this, so I could do for example:

curl http://mysite.example.com/admin-api/clear-cache?key=<secret>

This would be done remotely from a script. I'm thinking of this as a complement to drush, a kind of "remote drush" for the cases where you don't have ssh access to the server but you still want to automate things.

Is there a module for this? Or some other strategy?

Solution

You could write a small module that hooks into cron:

// function that will be triggered on next cron run
function <MODULE>_cron() {
   // clear all caches
   drupal_flush_all_caches();
}

Then you could simply run cron:

curl http://mysite.example.com/cron.php?cron_key=<YOUR_CRON_KEY>

Which in turn will trigger <MODULE>_cron() that will clear the cache.

Another approach would be to create a small module that adds a callback through hook_menu():

function <MODULE>_menu() {
  $menu['cache/clear/%'] = array(
    'page callback' => '<MODULE>_clear_cache',
    'access arguments' => array('access content'),
    'page arguments' => array(2)
  );
  return $menu;
}

function <MODULE>_clear_cache($cache) {
  // check so we have a valid access_token
  $access_token = variable_get('cache_access_token');
  $token = filter_input(INPUT_GET, 'access_token');
  if($token == $access_token) {
    switch($cache) {
      case 'all':
        drupal_flush_all_caches();
        break;
      case 'theme':
        cache_clear_all('theme_registry', 'cache', TRUE);
        break;
    }
  }
}

function <MODULE>_form_alter(&$form, &$form_state, $form_id) {
  if($form_id == 'system_site_information_settings') {
    // add a cache access token field under site information
    $form['cache_access_token'] = array(
        '#type' => 'textfield',
        '#title' => t('Access Token'),
        '#description' => t('Token used to access clear cache remotely'),
        '#default_value' => variable_get('cache_access_token')
    );
  }
}

Enable the module and you should be able to clear you cache by running:

curl http://mysite.example.com/cache/clear/all?access_token=<YOUR_ACCESS_TOKEN>

if you only would like to clear the theme cache you would do like this:

curl http://mysite.example.com/cache/clear/theme?access_token=<YOUR_ACCESS_TOKEN>

There is also a module called Clear Cache Remotely that I think does exactly what you want.