Using TCPDF with Symfony 2

Using TCPDF with Symfony2 is pretty simple. However there are a few problems that may arise.

namespace Acme\DemoBundle\Controller;

class PdfController extends Controller
{
    public function pdfAction()
    {
        $pdf = new \TCPDF();

        // Construct the PDF.

        $pdf->Output('filename.pdf');
    }
}

Easy enough. The PDF loads, but we get this error in the logs:

request.CRITICAL: Uncaught PHP Exception LogicException: "The controller must return a response (null given). Did you forget to add a return statement somewhere in your controller?"

We can fix that:

namespace Acme\DemoBundle\Controller;

use Symfony\Component\HttpFoundation\Response;

class PdfController extends Controller
{
    public function pdfAction()
    {
        $pdf = new \TCPDF();

        // Construct the PDF.

        $pdf->Output('filename.pdf');

        return new Response(); // To make the controller happy.
    }
}

Add some authentication and remember me tokens, close the browser, relaunch the browser, and visit the PDF page. We get a new error:

request.CRITICAL: Uncaught PHP Exception RuntimeException: "Failed to start the session because headers have already been sent by "[...]/vendor/tecnick.com/tcpdf/include/tcpdf_static.php"

Darn. TCPDF::Output() sends headers before Symfony has the chance. We can fix that too:

namespace Acme\DemoBundle\Controller;

use Symfony\Component\HttpFoundation\StreamedResponse;

class PdfController extends Controller
{
    public function pdfAction()
    {
        $pdf = new \TCPDF();

        // Construct the PDF.

        return new StreamedResponse(function () use ($pdf) {
            $pdf->Output('filename.pdf');
        });
    }
}

Perfect. Now Symfony and TCPDF::Output() can both send their headers, and everything plays nice.

Symfony 2: Using @ParamConverter with multiple Doctrine entities

Symfony 2 describes how to use parameter converters to translate slugs to entities, but their example does not enforce the relationship between the two entities. Here’s their example:

/**
 * @Route("/blog/{date}/{slug}/comments/{comment_slug}")
 * @ParamConverter("post", options={"mapping": {"date": "date", "slug": "slug"}})
 * @ParamConverter("comment", options={"mapping": {"comment_slug": "slug"}})
 */
public function showAction(Post $post, Comment $comment)
{
}

Assuming that Post has id and slug attributes and that Comment has id, post, and slug attributes, the above example does not require that the Post slug in the URL match the Comment’s Post. Here’s an example that requires that the Post and Comment are related:

/**
 * @Route("/blog/{post_date}/{post_slug}/comments/{slug}")
 * @ParamConverter("post", options={"mapping": {"post_date": "date", "post_slug": "slug"}})
 */
public function showAction(Post $post, Comment $comment)
{
}

This example works because Post is processed first and because $post is named the same as the Comment::$post relationship. When it comes time to process the Comment, it attempts to use slug and post to find the Comment instead of just slug. (No @ParamConverter annotation is necessary for the Comment because the parameters are named the same as the attributes.) If $post doesn’t match $comment->post, a 404 is returned, no additional checks required.