In 2009 we released a Google Analytics API client in PHP. It was the first library released in PHP. Six years later, this software is outdated. Google changed the API and it’s no longer of use.
As an alternative you can use GAPI (Github). Go to github.com/erebusnz/gapi-google-analytics-php-interface for instructions and to get the source code.
This is a basic example how you can use GAPI: