Install the PHP DOM Extension on CentOS

If you get error like:

Class 'XMLWriter' not found in /path/to/application/third_party/PHPExcel/Shared/XMLWriter.php on line 44

Let's get the solution. Here we cover the fastest, most effective way to get the PHP DOM extension installed on CentOS. If you’ve just found out you need to install this extension, but don’t really know what it is, we’ve included some background first.

What is DOM?

“The Document Object Model (DOM) is a cross-platform and language-independent convention for representing and interacting with objectsin HTMLXHTML and XML documents.” (Source: DOM in Wikipedia.)

What is PHP DOM extension?

“The DOM extension allows you to operate on XML documents through the DOM API with PHP 5.” (Source: Introduction to the PHP DOM Extension on php.net.)

How to install the PHP DOM Extension on CentOS

You will need superuser privileges. Run the following command:
sudo yum install php-xml
Don’t forget to restart Apache so PHP picks up the new extension:
sudo service httpd restart

How to Check PHP DOM is Installed

You can see PHP DOM is installed by creating a simple web page that calls the phpinfo()function:
<?php phpinfo(); ?>
When you go to this webpage in a browser, you should see this output for the dom extension if it’s installed:

dom

DOM/XMLenabled
DOM/XML API Version20031129
libxml Version2.6.26
HTML Supportenabled
XPath Supportenabled
XPointer Supportenabled
Schema Supportenabled
RelaxNG Supportenabled
Tested on CentOS 6.4