http://api.rubyonrails.org/classes/ActionController/AbstractRequest.html#M000461
domain(tld_length = 1)
content_type()
headers()
host()
host_with_port()
path_parameters()
path()
parameters()
port()
post?()
put?()
remote_ip()
request_uri()
subdomains(tld_length = 1)
