Woo-commerce 3.0 single product price is not changing properly

Question

I made a new post type named "sub_products" containing the meta tag "unit_price". After assigning a new field for every Woocommerce product containing a list of all the "sub_products" posts, the goal was to update every product price based on the selected "sub_products" meta "unit_price".

function kulcskron_edit_post( $p1, $p2 )
{
  if ( !is_admin() )
    return;

  if ( get_post_type() != 'product' )
    return;

  $sub_product_ids = $p2->get_meta( 'sub_products' );

  if ( empty($sub_product_ids) )
    return;

  $product_regular_price = 0;
  foreach ( $sub_product_ids as $id ) 
    $product_regular_price += get_post_meta( $id, 'unit_price', true );

  if ( $p1 == $product_regular_price )
    return;

  $p2->set_regular_price( $product_regular_price );
  $p2->save();
}
add_action( 'woocommerce_product_get_price', 'kulcskron_edit_post', 10, 2 );

I tried every possible hook to make this work:

add_action( 'the_post', 'kulcskron_edit_post', 9, 1 );
add_action( 'edit_post', 'kulcskron_edit_post', 10, 2 );
add_action( 'pre_get_posts', 'kulcskron_edit_post' );
add_action( 'save_post', 'kulcskron_edit_post' );

This code updates the price but in a strange way:

Admin single product edit view: The price is not updated right away, just after I revisit the edit screen.

Admin product listing view: Every price is 0.

Front-end product page view: The displayed price is 0.

How do I update the product price based on the assigned "sub_products" "unit_price" post meta when a single product is saved in admin view?

Answer 1

I managed to solve the price update problem. I used the save_post action:

save_post is an action triggered whenever a post or page is created or updated, which could be from an import, post/page edit form, xmlrpc, or post by email.

The final code:

function kulcskron_update_product( $product_obj )
{
  if ( !is_admin() )
    return;

  if ( get_post_type() != 'product' )
    return;

  $product = wc_get_product( $product_obj );
  if ( !$product->meta_exists( 'sub_products' ) )
    return;

  $sub_product_ids = $product->get_meta( 'sub_products' );
  if ( empty($sub_product_ids) )
    return;

  _update_product_price( $product_obj, $sub_product_ids );

}
add_action( 'save_post', 'kulcskron_update_product' );

And for the sake of completeness here is the rest of code:

function _update_product_price( $product_obj, $sub_product_ids )
{
  $product = wc_get_product( $product_obj );

  $product_regular_price = 0;
  foreach ( $sub_product_ids as $id ) 
    $product_regular_price += get_post_meta( $id, 'kulcskron_unit_price', true );

  $product->set_regular_price( $product_regular_price );
  $product->set_price( $product_regular_price );
  $product->save();
}

This way basically everything can be edited and updated. Example:

function _update_product_stock( $product_obj, $sub_product_ids )
{
  $product = wc_get_product( $product_obj );

  $sub_product_stocks = array();
  foreach ( $sub_product_ids as $id ) 
    $sub_product_stocks[] = get_post_meta( $id, 'kulcskron_free_stock_quantity', true );

  $product->set_manage_stock( true );
  $product->set_stock_quantity( min($sub_product_stocks) );
  $product->save();
}

I would love to post a link to all the methods to edit a product but I have no rep for that.

But sadly this is not all... In order to fully update the price, we need to filter the price HTML to return the newly updated price.

function kulcskron_price_html( $priceHtml, $product )
{
  $symbol = get_woocommerce_currency_symbol();
  $price = $product->get_regular_price();
  $html = '<span class="woocommerce-Price-amount amount">'. $price .'&nbsp;<span class="woocommerce-Price-currencySymbol">'. $symbol .'</span></span>';
  return $html;
}; 
add_filter( 'woocommerce_get_price_html', 'kulcskron_price_html', 10, 2 );

A little backstory. We need to sync all the products from an external database through an XML file. But there is a catch, the XML file only contains product parts and they are not displayed, searched, filtered and certainly can't be ordered individually. None of the Woocommerce build in functionality meet these requirements.

In order to solve this, I registered a new post type and imported all the product parts into this newly created post type. After that, I registered a new field for every WC Product with the Advanced Custom Fields plugin.

It looks like this: Newly registered custom post type with the custom fields

The code above makes easy to update the WC Products (e.g. Prices) based on the selected Sub products.

Answer 2

You may use the hook "woocommefrce_get_price_html" it should work