Statement PDFs in Symfony

Why statements become PDFs

A statement summarises a period that is now closed. Regenerating it later from live data would produce a different document, which defeats the point. That is the difference between a document and a view of a database, and it is why finance and account management keep asking for this.

What a statement has to carry

Before any of the code below matters, the template has to produce a document that is actually a statement. These are the fields that make it one, and the ones a reader or an auditor will look for first.

• the opening balance and the closing balance
• every transaction in the period with date, description and signed amount
• a running balance column, so a reader can find where a discrepancy starts
• the account identifier, usually masked
• the statement period, which must not overlap the previous one

Turning your Twig template into a document

You already have the markup. $this->renderView("invoice/pdf.html.twig", $data) gives you it as a string, which is the only input the render needs. Twig's asset() reads from the request context. In a console command or a message handler there is no request, so the base URL comes out empty and the paths in your markup are relative to nothing.

The Symfony implementation

HttpClientInterface is the client most projects here already have. The render happens in a controller returning StreamedResponse, and you wrap the response stream in a StreamedResponse.

<?php
// src/Controller/StatementController.php

namespace App\Controller;

use Symfony\Component\HttpFoundation\StreamedResponse;
use Symfony\Contracts\HttpClient\HttpClientInterface;

class StatementController extends AbstractController
{
    public function __construct(private HttpClientInterface $client) {}

    #[Route('/statements/{id}.pdf', name: 'statement_pdf')]
    public function pdf(Statement $statement): StreamedResponse
    {
        $html = $this->renderView('statement/pdf.html.twig', ['statement' => $statement]);

        $upstream = $this->client->request('POST', 'https://api.pdfpipe.xyz/v1/pdf', [
            'auth_bearer' => $this->getParameter('pdfpipe.key'),
            'json' => [
                'html' => $html,
                'options' => ['format' => 'A4', 'printBackground' => true],
            ],
            'timeout' => 60,
        ]);

        // The transfer happens here, on first read, not on request() above.
        return new StreamedResponse(
            function () use ($upstream) {
                foreach ($this->client->stream($upstream) as $chunk) {
                    echo $chunk->getContent();
                }
            },
            200,
            ['Content-Type' => 'application/pdf'],
        );
    }
}

The CSS that makes a statement page correctly

The layout problem specific to this document is that a long transaction table spanning many pages, needing repeated headers and a running balance that stays legible after a break. These rules handle it.

/* Line items run past one page. Repeat the header, keep the
   totals block whole, and never strand a single row. */
thead { display: table-header-group; }
tfoot { display: table-footer-group; }
tr    { break-inside: avoid; }

.totals {
  break-inside: avoid;
  break-before: auto;
}

@page {
  size: A4;
  margin: 18mm 16mm 22mm;
}

What goes wrong in Symfony

Symfony's HttpClient is lazy. request() returns before the response arrives, and the actual transfer happens when you first read the content. That means your timeouts and your try/catch have to be around the read, not around the call, or a failed render surfaces somewhere unexpected.

What people try first

Most Symfony projects reach for KnpSnappyBundle, a wrapper around the same wkhtmltopdf binary, with the same requirement that the binary exists everywhere the app runs. That works until it is running on more than one machine, at which point the browser becomes the thing you operate rather than the thing you use.

Where the statement lives afterwards

Rendering is the short part. Statements are the document most often requested again years later, usually for a loan application or an audit. Regenerating one from current data would produce different figures, so the rendered file is the record and has to be stored as issued.

Getting the document right

• Check the closing balance, which has to reconcile with the transactions listed above it.
• Generation is triggered by the end of a billing or accounting period, so size the timeout for that path rather than for a health check.
• This is a batch shape: render the run through the batch endpoint rather than firing thousands of individual requests.
• Backgrounds are painted by default here, so a design that uses colour needs nothing set. Only an explicit print_background of false turns them off.

Frequently asked

Related

Other Symfony documents, and the same statement in other stacks.