From: David Masover <ninja@...>
Date: 2009-08-29T11:20:36+09:00
Subject: Re: Implementig a XCAP web server:  Ebb and Rack ?

On Thursday 27 August 2009 04:28:20 pm Iñaki Baz Castillo wrote:
> - The client requests a XML document (GET) so the server replies it in the
> body of the 200 OK.
>
> - The client stores a XML document (PUT) in the server, so the server
> validates it and stores in a DB table.

Sounds very much like a REST architecture, which Rails (among others) is very 
good at.

> There are a lot of web servers built in Ruby and I'm getting a bit crazy by
> tryting to choose one.

Don't.

> I've read about Ebb web server (which seems to be
> very fast) and RACK (which seems to be a framework to build the application
> by receiving requests from the web service, Ebb in this case).

That's the point.

If you wanted to work close to the metal, you would use Rack. Your application 
would then be easily portable beween Ebb, Mongrel, Thin, Passenger/modrails, 
etc, without much work from you.

But if you use Rack, you shouldn't have to choose one of those other 
frameworks right away, in order to develop your app. Develop the app first, 
then try different webservers to see which one works best.

> Unfortunatelly, by reading the doc of RACK (Ebb has no doc at all) I can't
> figure how to build the application:

Rack itself is still not really friendly to work with.

If you don't want to learn Rails (which ultimately uses Rack), you could 
instead try something else. Sinatra might be the simplest. But even here, 
you're choosing between frameworks -- you shouldn't really have to think about 
all those other layers.

What I'm getting at is, say you want to use Sinatra. You would just do:

# gem install sinatra

Then, in your application, you'd do:

require 'rubygems'
require 'sinatra'

And then you'd forget Rack, or Ebb, or any of those other things even exist, 
until you need to tune your app for performance.

> A web server that receive a request and replies "200 OK" if the request URL
> is "/yes" and "404 Not Found" is the request URL is "/no".

Here's a simple Sinatra script:

require 'rubygems'
require 'sinatra'

get '/yes' do
  "Hello, World!\n"
end


Just run that, then try http://localhost:4567/yes, and you'll get 'Hello, 
World!' with a status code of 200. Anything else, you'll get a 404.