Display custom field value in WooCommerce single product pages via hook

I don’t know much about PHP yet, but I’m trying to place some content in my single product pages by using the woocommerce_before_add_to_cart_form hook.

I succeeded in making a code that prints my text and the Total sales of my products. The code looks like this:

add_action( 'woocommerce_before_add_to_cart_form', 'production_time', 11 );
  
function production_time() {
   global $product;
   $production_time = $product->get_total_sales();
   if ( $production_time ) echo '<p class="ri ri-clock">' . sprintf( __( ' Productietijd: %s', 'woocommerce' ), $production_time ) . '</p>';
}

But instead of product total sales I want my product custom field value to be displayed.

This is the custom field I added fullfilment_production_time custom field:

I tried changing the get_total_sales() to get_fullfilment_production_time() but that didn’t work.

I also tried this one:

add_action( 'woocommerce_before_add_to_cart_form', 'production_time', 11 );
  
function production_time() {
   global $product;
   $production_time = $product->get_post_meta( get_the_ID(), 'fullfilment_production_time', true );
   if ( $production_time ) echo '<p class="ri ri-clock">' . sprintf( __( ' Productietijd: %s', 'woocommerce' ), $production_time ) . '</p>';
}

Any advice?

Answer

There is a mistake in your code when using get_post_meta() function in a wrong way. You can use different ways to get a product custom field value:

1. The WooCommerce way using WC_Data method get_meta() this way:

add_action( 'woocommerce_before_add_to_cart_form', 'production_time', 11 ); 
function production_time() {
    global $product;

    $production_time = $product->get_meta( 'fullfilment_production_time' );

    if ( ! empty($production_time) ) {
        echo '<p class="ri ri-clock">' . sprintf( __( ' Productietijd: %s', 'woocommerce' ), $production_time ) . '</p>';
    }
}

2. The old WordPress way using get_post_meta() function this way:

add_action( 'woocommerce_before_add_to_cart_form', 'production_time', 11 ); 
function production_time() {
    global $product;

    $production_time = get_post_meta( $product->get_id(), 'fullfilment_production_time', true ); 
   
    if ( ! empty($production_time) ) {
        echo '<p class="ri ri-clock">' . sprintf( __( ' Productietijd: %s', 'woocommerce' ), $production_time ) . '</p>';
    }
}

3. For Advanced custom fields plugin using get_field() function this way:

add_action( 'woocommerce_before_add_to_cart_form', 'production_time', 11 ); 
function production_time() {
    global $product;

    $production_time = get_field( 'fullfilment_production_time', $product->get_id() ); 
   
    if ( ! empty($production_time) ) {
        echo '<p class="ri ri-clock">' . sprintf( __( ' Productietijd: %s', 'woocommerce' ), $production_time ) . '</p>';
    }
}