We use URL’s every day, but as a developer we have to know a bit more about their structure and the rules that apply to them.
This article does a good job of reviewing all these rules:
http://www.skorks.com/2010/05/what-every-developer-should-know-about-urls/
Some highlights:
<scheme>://<username>:<password>@<host>:<port>/<path>;<parameters>?<query>#<fragment>
One part I hadn’t realized was the “parameters” portion after the semicolon- this is apparnetly not used very frequently at all.
The article also discusses a lot of encoding and special character ruls for each portion of the url.