Very simple example, using RackBuilder to route two paths two two separate hosts.
Shows how routing is utilized to remap certain paths, or deny access.
Shows how a custom permission handler is injected to require a secret API token.
Shows an advanced example of how parts of the URL are rewritten, turning them into HTTP headers.
Shows an advanced example of how to programmatically inject a proc into the routes which makes multiple requests to form an aggregated response.