Drupal 7 Snippet: Add "Cancel" button to Content edit / create forms

Based on the snippet from Pascal Duez:
https://gist.github.com/pascalduez/1888373 (thanks a lot!) I modified a bit, here's a snippet to add a "Cancel" button in Content (Node) create / edit forms.

Simply use your own mini module to implement it.

/**
* Custom cancel button callback.
*/
function mymodule_form_cancel($form, &$form_state) {
$fallback_destinaton = '';
// If edit, use the node itself as fallback.
if (!empty($form['#node'])) {
if (!empty($form['#node']->nid)) {
$nid = $form['#node']->nid;
$node = node_load($nid);
$node_uri = node_uri($node);
$fallback_destinaton = $node_uri['path'];
}
}
// Go to destination or fallback.
$url = isset($_GET['destination']) ? $_GET['destination'] : $fallback_destinaton;
drupal_goto($url);
}
?>

function mymodule_form_alter(&$form, &$form_state, $form_id) {
if (stristr($form_id, '_node_form') !== FALSE) {
$form['actions']['cancel'] = array(
'#type' => 'submit',
'#value' => t('Cancel'),
'#access' => TRUE,
'#weight' => 999,
'#submit' => array('mymodule_form_cancel', 'node_form_submit_build_node'),
'#limit_validation_errors' => array(),
'#attributes' => array('class' => array('btn-cancel')),
);
}
}
?>

If the "Cancel" button is clicked, the user is being redirected the following way:

1. If a "destination" paramter is set, this is used
2. If no destination parameter is set and we're in an edit form, the user is being redirected to the node display
3. Otherwise the user is being redirected to the frontpage