Symfony 2 PDF service using LaTeX

# src/Electrotech/WeldqualBundle/Resources/config/services.yml

parameters:
    electrotech.twig.ib2020_extension.class: Electrotech\WeldqualBundle\Twig\Ib2020Extension
    electrotech.pdf.pdflatex.rubber-pipe: /usr/bin/rubber-pipe

services:
    electrotech.twig.ib2020_extension:
        class: %electrotech.twig.ib2020_extension.class%
        arguments: [%kernel.bundles%]
        tags:
            - { name: twig.extension }

    electrotech.pdf.pdflatex:
        class:        Electrotech\WeldqualBundle\Pdf\Pdflatex
        arguments:    [%electrotech.pdf.pdflatex.rubber-pipe%]

<?php
// src/Electrotech/WeldqualBundle/Pdf/Pdflatex.php

namespace Electrotech\WeldqualBundle\Pdf;

class Pdflatex
{

    /**
     * Full system path to rubber-pipe binary
     * @var string
     */
    private $binary;

    /**
     * Options for rubber-pipe
     * @var array
     */
    private $options = array(
        '--pdf' => null,
        '--into' => '/tmp/'
    );

    /**
     * Tex source document
     * @var string
     */
    private $texSource;

    /**
     * Generated PDF document
     */
    private $pdf;

    /**
     * Initial working dir
     * @var string
     */
    private $cwd = '/tmp/';

    /**
     * Environment variables
     * @var array|null
     */
    private $env = null;

    /**
     * Error output
     * @var string
     */
    private $stderr = null;

    /**
     * Return value
     * @var integer
     */
    private $returnValue;


    public function __construct($binary)
    {
        $this->binary = $binary;
    }

    /**
     * Create rubber-pipe command
     */
    public function getCommand()
    {
        $args = '';
        foreach ($this->options as $option => $value)
        {
            $args .= ' '.$option;
            if ($value !== null)
            {
                $args .= ' '.$value;
            }
        }
        return $this->binary.$args;
    }

    /**
     * Execute rubber-pipe command
     */
    public function execute()
    {
        $descriptorSpec = array(
            0 => array("pipe", "r"),
            1 => array("pipe", "w"),
            2 => array("pipe", "w"),
        );

        $process = proc_open(
            $this->getCommand(),
            $descriptorSpec,
            $pipes,
            $this->cwd,
            $this->env
        );

        if (is_resource($process)) {
            fwrite($pipes[0], $this->getTexSource());
            fclose($pipes[0]);

            $this->pdf = stream_get_contents($pipes[1]);
            $this->stderr = stream_get_contents($pipes[2]);
            $this->returnValue = proc_close($process);
        }

        if ($this->returnValue == 0)
        {
            return true;
        }
        return false;
    }

    /**
     * Set path to rubber-pipe binary
     * @param string $binary Full system path to rubber-pipe binary
     */
    public function setBinary($binary)
    {
        $this->binary = $binary;
    }

    /**
     * Get path to rubber-pipe binary
     * @return string Full system path to rubber-pipe binary
     */
    public function getBinary()
    {
        return $this->binary;
    }

    /**
     * Set LaTeX source
     * @param string $texSource LaTeX source document
     */
    public function setTexSource($texSource)
    {
        $this->texSource = $texSource;
    }

    /**
     * Get LaTeX source
     * @return string LaTeX source document
     */
    public function getTexSource()
    {
        return $this->texSource;
    }

    /**
     * Get PDF file contents
     * @return mixed Generated PDF file contents
     */
    public function getPdf()
    {
        return $this->pdf;
    }

    /**
     * Get errors
     * @return string Error output
     */
    public function getStderr()
    {
        return $this->stderr;
    }

    /**
     * Get return value
     * @return integer Return value from rubber-pipe command
     */
    public function getReturnValue()
    {
        return $this->returnValue;
    }

}

% src/Electrotech/WeldqualBundle/Resources/views/Testweld/show.tex.twig

% This template has been simplified for the sake of brevity.

\documentclass[10pt,a4paper]{article}

\usepackage{array}
\usepackage{calc}
\usepackage{color}
\usepackage{colortbl}
\usepackage{graphicx}
\usepackage[margin=1cm]{geometry}
\usepackage{multirow}
\usepackage{tabularx}
\usepackage{wasysym}

% width of table columns
\newlength{\colOneWidth}
\setlength{\colOneWidth}{0.13\textwidth}
\newlength{\colThreeWidth}
\setlength{\colThreeWidth}{0.13\textwidth}
\newlength{\colFourWidth}
\setlength{\colFourWidth}{0.25\textwidth}
\newlength{\colFiveWidth}
\setlength{\colFiveWidth}{0.13\textwidth}
\newlength{\colThreeToFiveWidth}
\setlength{\colThreeToFiveWidth}{\colThreeWidth + \colFourWidth + \colFiveWidth}
\newlength{\colFourToFiveWidth}
\setlength{\colFourToFiveWidth}{\colFourWidth + \colFiveWidth}


% colours
\definecolor{IB2020Blue}{RGB}{172,206,230} % #ACCEE6
\definecolor{invalidBg}{RGB}{242,222,222}  % #F2DEDE
\definecolor{invalidFg}{RGB}{185,74,72}    % #B94A48

% page style
\pagestyle{empty} % remove page numbering

% PDF meta data
\pdfinfo{
    /Title (Welder Qualification Certificate)
    /Creator (IB2020 {{ electrotech_system_owner | e_latex }})
    /Producer (IB2020 {{ electrotech_system_owner | e_latex }})
    /Author (IB2020 A Management Information System for Inspection Bodies)
    /CreationDate (D:{{ "now"|date("YmdGisO") | e_latex }})
    /ModDate (D:{{ "now"|date("YmdGisO") | e_latex }})
    /Subject (Welder Qualification Certificate)
    /Keywords (IB2020)
}


\begin{document}

% remove left indent from table
\noindent%
\begin{tabularx}{\textwidth}{@{}|p{\colOneWidth}|X|p{\colThreeWidth}|p{\colFourWidth}|p{\colFiveWidth}| }
    \hline
        \centering \scriptsize{}Certificate Number\newline \normalsize {{ entity.certificateNumber | e_latex }} &
        \multicolumn{3}{c|}{ \cellcolor{IB2020Blue} \textbf{Welder Qualification Certificate} } &
        \raisebox{-0.5\height}{
            \includegraphics[width=0.13\textwidth]{{ '{' }}{{ logoFile | e_latex }}{{ '}' }}
        } \\
    \hline
        \multicolumn{5}{|c|}{
            {{ electrotech_system_owner | e_latex }}
            \enspace
            IANZ Accredited Inspection Body No. {{ electrotech_ianz_number | e_latex }}
        } \\
    \hline
\end{tabularx}

\end{document}

<?php
// src/Electrotech/WeldqualBundle/Twig/Ib2020Extension.php

namespace Electrotech\WeldqualBundle\Twig;

use Twig_Extension;
use Twig_Filter_Method;
use Twig_Test_Method;

class Ib2020Extension extends Twig_Extension
{
    // Unrelated methods have been omitted from this code sample for the sake
    // of brevity.

    private $kernelBundles;

    public function __construct($kernelBundles)
    {
        $this->kernelBundles = $kernelBundles;
    }

    /**
     * Returns a list of filters to add to the existing list.
     *
     * @return array An array of filters
     */
    public function getFilters()
    {
        return array(
            'e_latex'     => new Twig_Filter_Method($this, 'escapeLatexFilter'),
        );
    }

    /**
     * Escape LaTeX special characters
     *
     * @return string
     */
    public function escapeLatexFilter($str = null)
    {
        $search = array('\\', '#', '$', '%', '&', '_', '{', '}', '~', '^',
            '>', '<');

        $replace = array('\textbackslash ', '\#', '\$', '\%', '\&', '\_',
            '\{', '\}', '\textasciitilde ', '\textasciicircum ',
            '\textgreater', '\textless');

        return str_replace($search ,$replace ,$str);
    }

    /**
     * Returns the name of the extension
     *
     * @return string The extension name
     */
    public function getName()
    {
        return 'electrotech_twig_ib2020_extension';
    }

}

<?php

// Utilising the PDF LaTeX service
$pdflatex = $this->get('electrotech.pdf.pdflatex');
$pdflatex->setTexSource($latexSource);
$pdf = $pdflatex->getPdf()

<?php

// src/Electrotech/WeldqualBundle/Controller/TestweldController.php

namespace Electrotech\WeldqualBundle\Controller;

use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpKernel\Exception\HttpException;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;

use Electrotech\WeldqualBundle\Entity\Testweld;
use Electrotech\WeldqualBundle\Entity\Testweldassessment;
use Electrotech\WeldqualBundle\Form\TestweldType;
use Electrotech\WeldqualBundle\Helper\QualificationRangeHelper;


/**
 * Testweld controller
 */
class TestweldController extends Controller
{
    // Unrelated methods have been omitted from this code sample for the sake
    // of brevity.

    /**
     * Creates a PDF certificate
     */
    public function pdfAction($id)
    {

        $latexSource = $this->latexSource($id, 'show.tex.twig');

        $pdflatex = $this->get('electrotech.pdf.pdflatex');
        $pdflatex->setTexSource($latexSource['latex']);

        if (!$pdflatex->execute())
        {
            throw new HttpException(500, 'Error creating PDF: '.$pdflatex->getStderr());
        }

        $response = new Response();
        $response->setContent($pdflatex->getPdf());
        $response->headers->set('Content-Type', 'application/pdf');
        $response->headers->set('Content-Disposition', 'inline; filename="'.$latexSource['filename'].'.pdf"');

        return $response;
    }

    /**
     * Creates LaTeX source
     */
    private function latexSource($id, $template)
    {
        $em = $this->getDoctrine()->getManager();

        $entity = $em->getRepository('ElectrotechWeldqualBundle:Testweld')->find($id);

        if (!$entity) {
            throw $this->createNotFoundException('Unable to find Testweld entity.');
        }

        $em = $this->getDoctrine()->getManager();

        $weldVariables = $em->getRepository('ElectrotechWeldqualBundle:Weldvariables')
            ->fetchWeldVariables(
                $entity->getQualificationstandard()->getEdition()->getTechdoc(),
                $entity->getProducttype(),
                $entity->getWeldtype(),
                $entity->getWeldposition(),
                $entity->getWelddirection()
            );

        $qualifiedRange = null;

        if ($weldVariables !== null)
        {
            $qualifiedRange = new QualificationRangeHelper(
                $entity->getProducttype(),
                $entity->getPipeod(),
                $weldVariables->getQualifiedweldvariablesid()
            );
        }

        $logoFile = $this->get('kernel')->getRootDir().DIRECTORY_SEPARATOR.
            $this->container->getParameter('electrotech_upload_dir').DIRECTORY_SEPARATOR.
            'sysowner'.DIRECTORY_SEPARATOR.'logo.pdf';

        $templating = $this->get('templating');

        $latexSource = $templating->render(
            'ElectrotechWeldqualBundle:Testweld:'.$template,
            array(
                'entity'         => $entity,
                'logoFile'       => $logoFile,
                'qualifiedRange' => $qualifiedRange,
            )
        );

        return array(
            'latex'    => $latexSource,
            'filename' => $entity->getFilename()
        );
    }
}