Provides a custom 'Back to overview' button - Block

custom_block_back_to_overview.php

<?php

/**
 * Implementation of hook_block_info().
 */
function custom_block_back_to_overview_block_info() {
  $blocks = array();

  $blocks['back-to-overview'] = array(
    'info' => t('CB - Back to overview'),
  );

  return $blocks;
}

/**
 * Implementation of hook_block_view().
 */
function custom_block_back_to_overview_block_view($delta='') {
  
  $block = array();
  
  global $language;
  
    switch ($delta) {
      case 'back-to-overview':
        // get url
        $path = array_filter(explode('/', $_SERVER['REQUEST_URI']));      
        
        // remove the last item (news detail)
        array_pop($path);
        
        // if language is fr remove the first item
        if($language->language != 'nl') {
          array_shift($path);
        }     
        
        // get source url               
        $source = implode('/', $path);
                  
        // get the node id for the url
        $nodeid = drupal_lookup_path('source', urldecode($source), $language->language);
              
        // make link
        $content = l(t('Back to overview'), $nodeid, array('attributes' => array('title' => t('Back to overview'))));
        
        // assign block content
        $block['content'] = $content;
                    
      break;
    
    }

    return $block;
}