Modifying the "quantity" text field

ajsleigh,

Under most circumstances, I would agree with you - a pack size would be the way to go. For this particular application, it is important to the client that each product describe a single part - regardless of the packaging.

Thanks,
-mike

Ryan,

Thanks for the advice - much appreciated. Always good to have a sanity check...

Anyway, I went ahead and implemented a custom module for this functionality utlilizing FormAPI. I'm including the code below in case it can help someone else. If you don't mind taking a quick look at it and letting me know if you see any glaring issues with it, I'd appreciate it.

Congrats on getting Commerce 1.0 out-the-door!

Thanks,
-mike

<?php

/*
 * Implements hook_form_alter().
 */
function mymodule_commerce_form_alter(&$form, &$form_state, $form_id) {

  // Find any "add to cart" forms on individual product displays and modify the quantity.
  //   field to account for quantity blocks.
  if (strpos($form_id, 'commerce_cart_add_to_cart_form_') === 0) {
    _mymodule_commerce_modify_productdisplay_quantity_widget($form);
  }

  // Find any shopping cart forms and modify the quantity fields to account for quantity blocks.
  if ($form_id == 'views_form_commerce_cart_form_default') {
    _mymodule_commerce_modify_shoppingcart_quantity_options($form);
  }
}

/*
 * Modify the quantity widget on Product Display nodes.
 */
function _mymodule_commerce_modify_productdisplay_quantity_widget(&$form) {
  // get the product id
  $pid = $form['product_id']['#value'];

  // get the options array if a select box is necessary
  $options = _mymodule_commerce_get_quantity_options($pid);
  
  // if options were returned, update the widget
  if (count($options)) {
    $form['quantity']['#type'] = 'select';
    $form['quantity']['#size'] = 1;
    $form['quantity']['#options'] = $options;
  }
}

/*
 * Modify the quantity widget in Shopping Carts.
 */
function _mymodule_commerce_modify_shoppingcart_quantity_options(&$form) {
  // loop through all of the quantity fields in the shopping cart form
  foreach ($form['edit_quantity'] as $key => $quantity_field) {
    if (is_array($quantity_field)) {
      // query the DB for each line item in order to get the product id
      $entity_type = 'commerce_line_item';
      $query = new EntityFieldQuery();
      $query->entityCondition('entity_type', $entity_type, '=')
            ->propertyCondition('line_item_id', $quantity_field['#line_item_id'], '=');
      $result = $query->execute();

      if (!empty($result[$entity_type])) {
        // load the full line item information
        $line_item = entity_load($entity_type, array_keys($result[$entity_type]));

        // get the options array if a select box is necessary
        $pid = $line_item[$quantity_field['#line_item_id']]->commerce_product['und'][0]['product_id'];
        $options = _mymodule_commerce_get_quantity_options($pid);

        // if options were returned, update the widget
        if (count($options)) {
          $form['edit_quantity'][$key]['#type'] = 'select';
          $form['edit_quantity'][$key]['#size'] = 1;
          $form['edit_quantity'][$key]['#options'] = $options;
        }
      }
    }
  }
}

/*
 * Helper function to modify quantity widgets (when necessary) when the quantity block
 *   is greater than 1 for a particular product.
 */
function _mymodule_commerce_get_quantity_options($pid) {
  $options = array();

  // get the product based on the product id and whether or not is has a Quantity Block greater than 1
  $entity_type = 'commerce_product';
  $query = new EntityFieldQuery();
  $query->entityCondition('entity_type', $entity_type, '=')
        ->propertyCondition('product_id', $pid, '=')
        ->fieldCondition('field_quantityblock', 'value', 1, '>');
  $result = $query->execute();

  if (!empty($result[$entity_type])) {
    $entities = entity_load($entity_type, array_keys($result[$entity_type]));

    // set up convenient variables for the Maximum Quantity and Quantity Block
    $max = $entities[$pid]->field_maxquantity['und'][0]['value'];
    $quantity_block = $entities[$pid]->field_quantityblock['und'][0]['value'];

    // if the Quantity Block is greater than 1, then swap out the quantity widget
    if ($quantity_block > 1) {
      $option = $quantity_block;
      while ($option < $max) {
        $options[$option] = $option;
        $option = $option + $quantity_block;
      }
    }
  }
  return $options;
}

Ryan,

Nope - the product data I needed wasn't already in the form, which is why I had to pull the entire product as well.

I'll update the code if our testing uncovers any issues.

Thanks,
-mike

Joe,

So you want to be able to specify a list of available quantities rather than automatically generating the list based on a "quantityblock" field, correct?

I suppose you can add a field to the product display where you can input the list of available quantities, then modify the code I wrote to pull from that field instead of pulling from the quantityblock field and doing the calculation.

I admit - it'll be a challenge for you to do unless you have some knowledge of PHP...

Thanks,
-mike