We'll introduce the basics of the web server part of Odoo in this chapter. Note that this covers the fundamental pieces. For high-level functionality, you should refer to Chapter 15, Web Client Development.
All of Odoo's web request handling is driven by the Python library werkzeug (http://werkzeug.pocoo.org). While the complexity of werkzeug is mostly hidden by Odoo's convenient wrappers, it is an interesting read to see how things work under the hood.