Installing and Configuring PDFlib with PHP 7.0 on Ubuntu 16.04

Introduction

This guide explains how to enable PDFlib support for PHP on Ubuntu, so PHP applications can generate PDFs using the PDFlib library.

One note upfront: the original version of this guide targeted PHP 7.0 and Ubuntu 16.04, both long past end-of-life. The steps below follow the same process but generalized to your actual current PHP version and Ubuntu release — check PDFlib’s download page for the current PDFlib version and matching PHP binding, since hardcoding an old version number (as the original did) can point you to a build that no longer matches your current PHP.

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Implementation

I. Prerequisites

• Ubuntu (or another Linux distribution) with Apache and PHP installed
• Root or sudo access
• Knowledge of your server’s architecture and PHP version

II. How PDFlib Fits Into PHP

• PDFlib ships as a PHP extension (.so file), specific to your PHP version and architecture
• PHP loads it at startup based on your php.ini configuration
• Once loaded, your PHP scripts can call PDFlib’s functions directly to generate PDFs

III. Download PDFlib

Check your server’s architecture, then download the matching PDFlib package from the official PDFlib site — the exact filename will include the current version number, which changes over time:

cd /usr/local/src
wget https://www.pdflib.com/binaries/PDFlib/<VERSION>/PDFlib-<VERSION>-Linux-x86_64-php.tar.gz
tar -xvf PDFlib-<VERSION>-Linux-x86_64-php.tar.gz
cd PDFlib-<VERSION>-Linux-x86_64-php/

Replace <VERSION> with the actual current version shown on PDFlib’s download page — don’t reuse an old version number from an outdated guide, since it may no longer be available or compatible with your PHP version.

IV. Find Your PHP Extension Directory

php -i | grep extension_dir

Note: The original command was php -ini, which isn’t a valid PHP flag. The correct flag is -i (info), as shown above.

This shows a path like /usr/lib/php/20220829 — the exact directory number is specific to your PHP version’s ABI.

V. Copy the Extension File

Inside the extracted PDFlib folder, find the .so file matching your PHP version (for example, bind/php/php-82/php_pdflib.so for PHP 8.2), then copy it:

cp bind/php/php-<YOUR_PHP_VERSION>/php_pdflib.so /usr/lib/php/<YOUR_EXTENSION_DIR>/

VI. Add the Extension to php.ini

vi /etc/php/<YOUR_PHP_VERSION>/apache2/php.ini

Add:

extension=php_pdflib.so

VII. Verify Apache Configuration and Restart

apachectl -t

If it returns Syntax OK, restart Apache:

systemctl restart apache2

The original guide used /etc/init.d/apache2 graceful, which still works on many systems, but systemctl restart apache2 is the current standard approach on systemd-based distributions.

VIII. Verify

Create a phpinfo() test file and load it in your browser to confirm the PDFlib section appears.

IX. Conclusion

Enabling PDFlib for PHP comes down to matching the extension file to your exact PHP version and extension directory, then registering it in php.ini. Always check PDFlib’s current download page rather than reusing an old version number, and use php -i (not -ini) when locating your extension directory.

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Frequently Asked Questions

Why doesn’t PDFlib show up in phpinfo after restarting? Usually a mismatched PHP version between the .so file and your actual PHP installation, or an incorrect extension_dir path — double-check both against your php -i output.

Is PDFlib free to use? PDFlib offers both a free trial/lite version and paid licensed versions with additional features — check their site for current licensing details.

Do I need to rebuild the extension for each PHP update? Yes — since the .so file is tied to a specific PHP ABI version, updating PHP typically requires downloading and installing the matching PDFlib build again.

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