Serving XHTML is often misunderstood by php developers. Frontend engineers simply include the XHTML doctype to their documents, without actually serving document as XHTML. This triggers majority of the browsers to treat such pages as 'tag-soup'. [...] This front controller plugin's code mostly takes concepts from the excellent article by Keystone Websites, but implements in Zend Framework environment in an object-oriented way.

The code works as a plugin to the controller and runs a few checks on the contents of the data being pushed out (dispatchLoopShutdown) and returns the correct header information (DOCTYPE, language attribute) in the correct XHTML format for the data. When the plugin is registered, all it takes is a call to the "doctype()" method to output the correct information.

One thing I need to do while building the multi-user version of webme is to convert it so file references such as /f/photos/an_image.jpg get transparently converted so they serve correctly, even though the actual file may be located somewhere entirely else.

There's two steps involved - rewriting the URL request for the types of files you'd like to pull through the script (using some mod_rewrite magic in Apache) and make the script to do the actual work. Source for that is included too. Not only can something like this help you keep things organized but it also allows for extra security if you need to store the files outside of the webserver's document root.