Organic Groups for developers

This is a placeholder for different code snippets related to the organic groups module.

Allow only a single group for every group post.

In OG every group post can be associated with several group nodes. Here's the code you can use to force it to accept only a single group per post.

// Some hook_alter() function that calls _og_form_alters_audience_form_alter().

/**
 * Helper function; Make the groups audience accept only a single group.
 */
function _og_form_alters_audience_form_alter(&$form) {
  if (!empty($form['og_nodeapi']['visible']['og_groups'])) {
    $form['og_nodeapi']['visible']['og_groups']['#multiple'] = FALSE;
    // Add own submit handler so we can cast the groups back to an array.
    $form['#submit'][] = 'og_form_alters_audience_form_alter_submit';
  }
}

/**
 * Submit handler; Since we permit only a single group per content, we need to
 * case to groups into an array
 */
function og_form_alters_audience_form_alter_submit($form, &$form_state){
  if (!empty($form_state['values']['og_groups']) && !is_array($form_state['values']['og_groups'])) {
    $form_state['values']['og_groups'] = drupal_map_assoc((array)$form_state['values']['og_groups']);
  }
}