A tutorial of AWStats, at the end there are many useful reference of factor affect analysis information, especially useful is information about web caching
http://www.onlamp.com/lpt/a/6395

Introducing a python http library, with a lot of caching reference
http://www.xml.com/lpt/a/2006/02/01/doing-http-caching-right-introducing-httplib2.html

图解 HTTP 缓存 - https://www.infoq.cn/article/AIwqlgtlk2efT5Yi7doY