From: Lake Denman <lake@...>
Date: 2012-01-04T04:52:17+09:00
Subject: Re: Create web application using ruby not with frameworks

On 01/04/12 at 04:46am, Brian Candler wrote:
> Nike Mike wrote in post #1039276:
> > How to create web application only with ruby language and not with the
> > frameworks
> 
> It depends what you mean 'not with the frameworks', because I think 
> you're bound to use some sort of framework at some level.
> 
> (1) You could write your own web server from scratch in pure Ruby. But 
> then you'd be better off using webrick which is already supplied as part 
> of the Ruby standard library. Google for examples of how to write a web 
> app directly with webrick.
> 
> (2) You could write your app using the FastCGI protocol and run it under 
> mod_fcgi. But then your code needs to talk the FastCGI protocol, so 
> you'll probably end up using the fcgi library to handle this for you.
> 
> The trouble with (1) and (2) are that your app is hard-coupled to 
> webrick or fcgi, and it can't use any of the other fine and efficient 
> ruby webservers out there (e.g. mongrel, thin, unicorn, rainbows etc), 
> unless you change your app to work with the specific webserver.
> 
> (3) So, to solve this problem, you will probably want to use Rack. Rack 
> is an adapter which maps HTTP requests to simple Ruby call(). If you 
> write your app to the Rack API then it will work with any of the 
> webservers listed above, and also Phusion Passenger (a.k.a. mod_rails, 
> but it's really mod_rack)
> 
>     # config.ru
>     MyApp = lambda { |req|
>         return [200, {"Content-Type"=>"text/html"}, "Hello world!"]
>     }
>     run MyApp
> 
>     # To start, type 'rackup'. Then point web browser
>     # at http://127.0.0.1:9292/
> 
> (4) That's still a pretty low-level way of writing web applications, so 
> you could then look at a lightweight framework like Sinatra which sits 
> on top of rack.
> 
>     # hello.rb
>     require 'sinatra'
>     get '/' do
>         'Hello, world!'
>     end
> 
> Very nice: map verb (get) and path (/) to ruby code to execute. Sinatra 
> can also expand erb and haml templates and is easy to extend.
> 
> (5) And of course there are the big frameworks like Rails, which you 
> said you don't want to use, but they also just sit on top of Rack these 
> days.
> 
> So even if you "don't want to use a framework", I'd certainly recommend 
> going for at least option (4). It gives you maximum flexibility in terms 
> of options for deploying your code.
> 
> If you were thinking of something which would run erb directly, so your 
> pages are HTML with ruby embedded (like PHP), then don't. Nobody does 
> this any more, and the options for doing it are unmaintained and likely 
> to make you hate yourself and/or ruby if you try them.
> 
> Regards,
> 
> Brian.
> 
> -- 
> Posted via http://www.ruby-forum.com/.
> 
Nice answer, Brian. 

I would also recommend giving rack a go!