I know this is a dead simple library, but I’ve been wanting this forever and just not getting around to it. Tanaka Akira presents webapp, a generic interface for writing server-neutral CGIs. Supports CGI, FastCGI,i WEBrick, mod_ruby and command-line interface. This goes in Hobix.

 #!/path/to/ruby
 require 'webapp'

 WebApp do |webapp|
   webapp.puts <<_END_
     current time: #{Time.now}
     pid: #{$$}
     self: #{self.inspect}

     request_method: #{webapp.request_method}
     server_name: #{webapp.server_name}
     server_port: #{webapp.server_port}
     script_name: #{webapp.script_name}
     path_info: #{webapp.path_info}
     query_string: #{webapp.query_string}
     server_protocol: #{webapp.server_protocol}
     remote_addr: #{webapp.remote_addr}
     content_type: #{webapp.content_type}

     --- request headers ---
 _END_
   webapp.each_request_header do |k, v|
     webapp.puts "#{k}: #{v}" 
   end
 end

If you’re wondering why the documentation is so sparse, it’s because of all the delegators used in the WebApp class.

 extend Forwardable
 def_delegators :@response_body, :<<, 
   :print, :printf, :putc, :puts, :write

 def_delegator :@request_header, :each, :each_request_header
 def_delegator :@request_header, :[], :get_request_header

 def_delegator :@request, :request_method, :request_method
 def_delegator :@request, :server_name, :server_name
 def_delegator :@request, :server_port, :server_port
 def_delegator :@request, :script_name, :script_name
 def_delegator :@request, :path_info, :path_info
 def_delegator :@request, :query_string, :query_string
 def_delegator :@request, :server_protocol, :server_protocol
 def_delegator :@request, :remote_addr, :remote_addr
 def_delegator :@request, :content_type, :request_content_type

 def_delegator :@response_header, :set, :set_header
 def_delegator :@response_header, :add, :add_header
 def_delegator :@response_header, :remove, :remove_header
 def_delegator :@response_header, :clear, :clear_header
 def_delegator :@response_header, :has?, :has_header?
 def_delegator :@response_header, :[], :get_header
 def_delegator :@response_header, :each, :each_header

WebApp doesn’t require the CGI module, so be sure to require it yourself if you need the encoding methods and such. (via del.icio.us)