3rd Party Application - View Confluence Articles

I am working on a 3rd party app that I would like to connect to confluence. All I really want is to have the ability to allow users to VIEW ONLY specific confluence articles via html / php / java etc… Right now I am writing an application in PHP, and I would like to have the application just show the end user the article. Preferably to view the article in PDF format, or through an iFrame. I am sure each article in confluence has a article ID attached to it. Please let me know if there are any specific questions you may have and thank you for your time and assistance.