php-mf2

 php-mf2  is a superb open source PHP microformats2 parser that also supports classic microformats per the microformats2 parsing specification.

Composer
php-mf2 has PHP Composer support and that is the recommended way to install and use it.

Just one file
You can also use php-mf2 with the "just use this one file" approach by following the instructions at https://github.com/indieweb/php-mf2#installation "You could install it by just downloading /Mf2/Parser.php and including that"