PDF generation from XHTML in a LAMP environment

The LAMP environment is widely used for web development, and it is an acronym for Linux, Apache, MySQL, and PHP. This environment is an open-source platform that is easy to use and deploy. PDF format is commonly used for sharing and exchanging documents over internet. However, generating PDF documents can be a challenging task in a LAMP environment, especially when converting XHTML documents. In this article, we will explore different methods used for PDF generation from XHTML in a LAMP environment.

What is XHTML?

XHTML stands for Extensible Hypertext Markup Language, which is a markup language that is used to create web pages. It is an extension of HTML language and is based on XML. XHTML is a stricter and more structured version of HTML, and it is designed to be compatible with XML. This means that it follows a set of rules and guidelines, making it easier for web developers to create web pages that are compatible with various web browsers.

PDF Generation Methods

PDF generation from XHTML involves converting an XHTML document into a PDF document. There are different methods used for PDF generation from XHTML in a LAMP environment

DOMPDF

DOMPDF is a PHP library that is used to convert HTML and XHTML documents to PDF format. It is an open-source library that is easy to use and deploy in a LAMP environment. DOMPDF uses CSS (Cascading Style Sheets) standard to format HTML and XHTML documents, making it easy for web developers to create PDF documents that are consistent with original HTML and XHTML documents.

Installation: Download DOMPDF from https://github.com/dompdf/dompdf or install via Composer: composer require dompdf/dompdf

<?php 
    require_once 'dompdf/autoload.inc.php'; 
    use Dompdf\Dompdf; 
    
    $dompdf = new Dompdf(); 
    $html = file_get_contents('test.html'); 
    $dompdf->loadHtml($html); 
    $dompdf->setPaper('A4', 'landscape'); 
    $dompdf->render(); 
    $dompdf->stream("test.pdf", array("Attachment" => false)); 
?>

In above code, we first require DOMPDF library and create a new DOMPDF object. We then load HTML or XHTML document using file_get_contents() function and set paper size to A4 with a landscape orientation. Finally, we render PDF document and stream it to browser with filename "test.pdf".

TCPDF

TCPDF is another PHP library that is used to generate PDF documents from HTML and XHTML documents. It is an open-source library that is easy to use and deploy in a LAMP environment. TCPDF is a powerful library that offers a wide range of features, including support for multiple languages and character sets, encryption and compression of PDF documents, and support for HTML and XHTML documents.

Installation: Download TCPDF from https://tcpdf.org or install via Composer: composer require tecnickcom/tcpdf

<?php 
    require_once('tcpdf/tcpdf.php'); 
    
    $html = file_get_contents('test.html'); 
    $pdf = new TCPDF(PDF_PAGE_ORIENTATION, PDF_UNIT, PDF_PAGE_FORMAT, true, 'UTF-8', false); 
    $pdf->SetCreator(PDF_CREATOR); 
    $pdf->SetAuthor('Author Name'); 
    $pdf->SetTitle('Title'); 
    $pdf->SetSubject('Subject'); 
    $pdf->setFontSubsetting(true); 
    $pdf->AddPage(); 
    $pdf->writeHTML($html, true, false, true, false, ''); 
    $pdf->Output('test.pdf', 'I'); 
?>

In above code, we first require TCPDF library and create a new TCPDF object. We then load HTML or XHTML document using file_get_contents() function and set PDF metadata (creator, author, title, and subject). Finally, we add a new page to PDF document, write HTML or XHTML document to page, and output PDF document to browser with filename "test.pdf".

mPDF

mPDF is a PHP library that is used to generate PDF documents from HTML and XHTML documents. It is an open-source library that is easy to use and deploy in a LAMP environment. mPDF is a powerful library that offers a wide range of features, including support for Unicode characters, HTML and XHTML documents, and multiple languages.

Installation: Install via Composer: composer require mpdf/mpdf

<?php 
    require_once __DIR__ . '/vendor/autoload.php'; 
    
    $mpdf = new \Mpdf\Mpdf(); 
    $html = file_get_contents('test.html'); 
    $mpdf->WriteHTML($html); 
    $mpdf->Output(); 
?>

In above code, we first require mPDF library and create a new mPDF object. We then load HTML or XHTML document using file_get_contents() function and write HTML or XHTML document to PDF document. Finally, we output PDF document to browser.

wkhtmltopdf

wkhtmltopdf is an open-source command-line tool that is used to convert HTML and XHTML documents to PDF format. It is based on WebKit rendering engine, which is used by popular web browsers such as Google Chrome and Safari. wkhtmltopdf offers a wide range of features, including support for CSS, JavaScript, and images.

Installation: Install on Ubuntu/Debian: sudo apt-get install wkhtmltopdf

To use wkhtmltopdf, we can execute it via PHP using shell_exec()

<?php
    $command = 'wkhtmltopdf test.html test.pdf';
    $output = shell_exec($command);
    echo "PDF generated successfully!";
?>

Comparison

Conclusion

PDF generation from XHTML in a LAMP environment can be accomplished using various methods. DOMPDF, TCPDF, mPDF, and wkhtmltopdf are commonly used solutions, each with distinct advantages. Choose based on your specific requirements: wkhtmltopdf for complex layouts with JavaScript, mPDF for Unicode support, or DOMPDF for simple CSSstyled documents.