furthermore -as a more direct answer to the question

a) there’s no provision for that because
b) in 99% of cases (exceptions prove the rule and all that and might work for some prices) it will not be what’s required anyway
assuming you have prices like 9.95, 7.95 and 5.95 if one were to blanket apply 10% you’d end up with 8.96, 7.16, 5.36
I dont think anyone will want these kind of odd prices so you’d have to do most of them manually anyway

>Any update yet about the issue?
no, becuase epay.dk have not replied to my re-activation of my test account nor have they setup a new test account i applied for (yet, on both counts)

re class: correct

have you tried a simple
file_put_contents('path/to/some/file.log', print_r($details_completed, true));

right after
function my_order_app($order_id, $details_completed) {

and had a look at that file

simply dont put a cart of the view only page

I’m not disputing that it works for you (how could I . I dont have one of these printers)
All I’m saying is that you are causing unnecessary overheads by getting the parameters again when they already exist
and if you one day decide to add another customer formfield for example (or remove one for that matter) you will have to add it to this script again wheras a simple foreach loop in the first place would already take care of that

again. i would suggest you change your action as mentioned, get rid of the ‘new order class’ etc and use the parameter available
(and perhaps brush up on how wordpress action/filter priorities and parameters work )

As a sidenote while I am here, I would also suggest something a bit more dynamic regarding the “all other order details” as they are variable and not always the same everywhere
perhaps something along these lines (will no doubt need tweaking according to what goodcom printers really need, but as a starting point)

$additional_data = array();

/* customer data */
$customer_data = array();
foreach($order[customer] as $k=>$v){
  $customer_data[$k]=$v['value'];//or value_formatted
}
$additional_data[] = '{'.implode('};{', $customer_data).'}';//tweak as required

/* order vars */
$ordervars= array();
foreach($order[ordervars] as $k=>$v){
  $ordervars[$k]=$v['value'];//or value_formatted
}
$additional_data[] = '{'.implode('};{', $ordervars).'}';//tweak as required

/* add $order[summary] too (this will always be 2 levels deep to account for multiple taxrates for example) so somewhat as above but a 2 level/nested foreach loop*/

/* then put it together - assuming it needs "*" between things - probably needs tweaking too as i dont know what those printers need but I would think one gets the idea*/
$txt .= implode('*', $additional_data);

as it happens i’ve just finished something would allow you to do that (and a bunch of other things)
that includes twilio,clickatell or tm4b (or simple email confirmation)

might be a couple of days or so until it’s available though

simply save the $order_details array into a file somewhere and have a look at the array
it should be quite self explanatory what is what

i.e something like file_put_contents(‘../ordini.txt’, print_r($order_details , true));

and then build your actual string as you need it

(and perhaps the same with the other parameters like the $print_templates vars etc etc )

@justin
technically speaking you should really start your own topic, but given that this is somewhat closely related let’s keep it going here for now as it might be interesting for anyone else that deals with goodcom printers (sorry proof)

now, regarding your code above (@justin)
a) your $txt = ... and file_put_contents.. will do nothing (for starters your return statement is before the file_put_contents..)

b) your $template_ids[] = 1; however makes the third parameter in wppizza_on_order_execute https://docs.wp-pizza.com/developers/?section=action-wppizza_on_order_execute contain the template stuff.
so you can now use that parameter in that wppizza_on_order_execute hook

i.e simplify your above filter to just be

add_filter('wppizza_on_order_execute_get_print_templates_by_id', 'my_prefix_my_filter');
function my_prefix_my_filter($template_ids){
	$template_ids[] = 1;
	return $template_ids;
}

and then do what you need to do with third parameter in the wppizza_on_order_execute
i.e

add_action('wppizza_on_order_execute', 'my_prefix_my_action', 10, 3);
function my_prefix_my_action($order_id, $order_details, $print_templates){
	/* 
	do something here with the now available $print_templates parameter 

	like  file_put_contents('../ordini.txt', $mystuff, FILE_APPEND);
	
	etc etc etc 
*/
}

please read the thread .
it says it all there . i.e

https://docs.wp-pizza.com/developers/?section=action-wppizza_on_order_execute