How to save invoice in pdf format?

Question

1C-Bitrix

I need to make it so that in the sale.order.ajax module where the invoice is displayed, so that when the link is generated, a pdf invoice of this receipt is generated. That is, the received data contains the received html layout.
Just a previous developer or a standard solution looks like this

<tr>
                  <td>
                                        <? if (strlen($arPaySystem["ACTION_FILE"]) > 0 && $arPaySystem["NEW_WINDOW"] == "Y" && $arPaySystem["IS_CASH"] != "Y"): ?>
                      <?
                      $orderAccountNumber = urlencode(urlencode($arResult["ORDER"]["ACCOUNT_NUMBER"]));
                      $paymentAccountNumber = $payment["ACCOUNT_NUMBER"];
                      ?>
                      <script>
                        window.open('<?=$arParams["PATH_TO_PAYMENT"]?>?ORDER_ID=<?=$orderAccountNumber?>&PAYMENT_ID=<?=$paymentAccountNumber?>');
                      </script>
                    <?=Loc::getMessage("SOA_PAY_LINK", array("#LINK#" => $arParams["PATH_TO_PAYMENT"]."?ORDER_ID=".$orderAccountNumber."&PAYMENT_ID=".$paymentAccountNumber))?>
                    <? if (CSalePdf::isPdfAvailable() && $arPaySystem['IS_AFFORD_PDF']): ?>
                    <br/>
                      <?=Loc::getMessage("SOA_PAY_PDF", array("#LINK#" => $arParams["PATH_TO_PAYMENT"]."?ORDER_ID=".$orderAccountNumber."&pdf=1&DOWNLOAD=Y"))?>
                    <? endif ?>
                    <? else: ?>
                      <?=$arPaySystem["BUFFERED_OUTPUT"]?>
                    <? endif ?>
                  </td>
                </tr>

The link does not always $arPaySystem['IS_AFFORD_PDF']) = falsedisplay, but the link turned out to be clumsy, because it does not lead to downloading a pdf file, but to a non-existent page. I don’t understand how to be here
And yes, there is no payment.php file in the order. What should be kept there?

Answer 1

payment.phpconnects after placing an order at the moment of transition to payment, usually displays either a receipt or a form for sending data to the payment gateway.

I need to make it so that in the sale.order.ajax module where the invoice is displayed, so that when the link is generated, a pdf invoice of this receipt is generated.

Theory: buffer the html receipts, pass the resulting html to any library that can generate pdf from html. Now about your code: see where $arPaySystem['IS_AFFORD_PDF'] is formed and why it is false.