no_render_add_to_cart.module

<?php
/**
 * @file
 * No render 'Add to cart' form module.
 */

// @todo Define as a module setting.
define('NO_RENDER_ADD_TO_CART_AJAX', TRUE);

/**
 * Implements hook_menu().
 */
function no_render_add_to_cart_menu() {
  $items['no-render-add/nojs'] = array (
    'page callback' => 'no_render_add_to_cart_callback',
    'page arguments' => array(1),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );
  $items['no-render-add/ajax'] = array (
    'delivery callback' => 'ajax_deliver',
  ) + $items['no-render-add/nojs'];
  return $items;
}

/**
 * Implements hook_views_api().
 */
function no_render_add_to_cart_views_api(){
  return array(
    'api' => 3,
    'path' => drupal_get_path('module', 'no_render_add_to_cart') . '/views',
  );
}

/**
 * Implements hook_theme().
 */
function no_render_add_to_cart_theme(){
  return array(
    'no_render_add_to_cart_form' => array(
      'template' => 'templates/no-render-add-to-cart-form',
      'arguments' => array(
        'product_id' => NULL,
      ),
    ),
  );
}

/**
 * Implements hook_field_extra_fields().
 */
function no_render_add_to_cart_field_extra_fields() {
  $extra = array();
  foreach (commerce_product_types() as $type => $product_type){
    $extra['commerce_product'][$type]['display'] = array(
      'add_to_cart' => array(
        'label' => t("Non FORM-API 'Add to cart form'"),
        'weight' => 0,
      ),
    );
  }
  return $extra;
}

/**
 * Implements hook_entity_view()
 */
function no_render_add_to_cart_entity_view($entity, $type, $view_mode, $langcode){
  if ($type == 'commerce_product') {
    $vars = array(
      'product_id' => $entity->product_id,
    );
    $entity->content['add_to_cart'] = array(
      '#markup' => theme('no_render_add_to_cart_form', $vars),
      '#weight' => 0,
    );

    if (NO_RENDER_ADD_TO_CART_AJAX) {
      drupal_add_library('system', 'drupal.ajax');
      drupal_add_library('system', 'jquery.form');
      drupal_add_js(drupal_get_path('module', 'no_render_add_to_cart').'/js/no_render_add_to_cart_ajax.js', 'file');
    }
  }
}

/**
 * Hook menu callback.
 *
 * Adds product into a cart.
 *
 * @see no_render_add_to_cart_menu()
 */
function no_render_add_to_cart_callback($ajax) {
  $quantity = 1;
  if(!empty($_POST['quantity']) && is_numeric($_POST['quantity'])){
    $quantity = $_POST['quantity'];
  }

  // Adding product into a cart.
  try {
    $product = commerce_product_load($_POST['product_id']);
    $line_item = commerce_product_line_item_new($product, $quantity);

    $line_item_wrapper = entity_metadata_wrapper('commerce_line_item', $line_item);
    $line_item_wrapper->commerce_display_path = token_replace('[commerce-product:node-link-path]', array('commerce-product' => $product));

    drupal_alter('commerce_product_calculate_sell_price_line_item', $line_item);
    rules_invoke_event('commerce_product_calculate_sell_price', $line_item);

    global $user;
    $uid = $user->uid;
    commerce_cart_product_add($uid, $line_item, TRUE);
  }
  catch (Exception $e) {
    watchdog_exception('no_render_add_to_cart', $e);
    throw $e;
  }

  if ($ajax == 'ajax') {
    $commands = array();

    // @todo expose cart block and its selector into a setting.
    $block = module_invoke('commerce_cart', 'block_view', 'cart');
    $commands[] = ajax_command_html('#block-commerce-cart-cart .content', render($block['content']));

    // Taking care about the messages.
    $commands[] = ajax_command_remove('div.messages');
    $commands[] = ajax_command_after('#main-content', theme('status_messages'));

    return ['#type' => 'ajax', '#commands' => $commands];
  }
  else {
    drupal_goto($_SERVER['HTTP_REFERER']);
  }
}