title: Merb - All You Need, None You Don't
gradient: top-bottom black grey


h1. Merb - All You Need, None You Don't

(Adapted S9 Version from "Original PDF Slide Deck":http://brainspl.at/articles/2008/03/29/mountain-west-rubyconf-merb-slides by Ezra Zygmuntowicz, Engine Yard @ Mountain West RubyConf 2008)

h1. Guiding Principles of Merb Development

* Prefer simplicity over magic as much as possible
* This is framework code, no @&:foo@ or returning allowed!
* When in doubt... benchmark and profile
* Know your runtime and how it acts


h1. Merb’s Motto

No code is faster than no code.


h1. Why? Why Not?

* Developer time is expensive...
* Servers are cheap...

h1. Who Cares About Efficiency

Just throw more servers at the problem!

Throwing more servers at the problem only goes so far ...

Of course I’m happy to sell you more servers ;) 

h1. Who Cares About Efficiency Continued 

Premature Optimization is the root of blah blah blah...

*Postmature Optimization* is the root of all hosting bills ;)


h1. What’s New?

* merb-core
** Rack Webserver Abstraction Layer  
** Powerful Router
** Provides API
* merb-more
* merb-plugins


h1. merb-core - Rack Webserver Abstraction Layer

* Ebb
* Evented Mongrel
* FastCGI
* Mongrel
* Thin
* Webrick


@config/rack.rb@:

{{{
class ApiHandler
  def initialize(app)
    @app = app
  end

  def call(env)
    request = Merb::Request.new(env)
    if request.path =~ %r{/api/(.*)}
     [200,
       {"Content-Type" => "text/json"},
       Api.get_json($1)]
    else
     @app.call(env)
    end
  end
end

use ApiHandler
run Merb::Rack::Application.new
}}}


h1. merb-core - Powerful Router 

{{{
Merb::Router.prepare do |r|
  r.resources :posts do |post|
    post.resources :comments
  end
end
}}}

Named Routes:

|Name|Route|
|delete_post_comment| /posts/:post_id/comments/:id/delete |
|post_comments      | /posts/:post_id/comments  |
|new_post           | /posts/new  |
|posts              | /posts  |
|post_comments      | /posts/:post_id/comments/:id |
|edit_post          | /posts/:id/edit |
|post               | /posts/:id  |
|new_post_comment   | /posts/:post_id/comments/new  |
|delete_post        | /posts/:id/delete  |
|edit_post_comment  | /posts/:post_id/comments/:id/edit  |


h1. merb-core - Powerful Router Continued

{{{
Merb::Router.prepare do |r|
  r.match(%r[^/foo/(.+)], :user_agent => /(MSIE|Gecko)/).
    to(:controller => 'foo', :title => '[1]',
       :action => 'show', :agent => ':user_agent[1]')

  r.match('/bar/:baz').defer_to do |request, params|
    if bar = Bar.find_by_baz params[:baz]
      {:controller => bar.controller,
       :action     => bar.action,
       :bar        => bar.to_param}
    end
  end
end
}}}


h1. merb-core - Provides API

{{{
Merb.add_mime_type(:yaml, :to_yaml, %w[application/x-yaml text/yaml])
Merb.add_mime_type(:html, :to_html, %w[text/html application/xhtml+xml application/html])
Merb.add_mime_type(:xml,  :to_xml,  %w[application/xml text/xml application/x-xml], :Encoding => 'UTF-8')
Merb.add_mime_type(:json, :to_json, %w[application/json text/x-json])
}}}

{{{
class Posts < Application
  provides :json, :yaml, :xml

  def show(id)
    @post = Post.find id
    display @post
  end
end
}}}

h1. merb-more - What’s New?

* Code Generators
* Asset Bundling
* Mailers and Parts
* Haml and other templating support
* Action Args
* Caching
* Other essentials

h1. merb-plugins - What’s New?

* merb_datamapper
* merb_activerecord
* merb_sequel
* merb_helpers
* merb_param_protection
* many more to come

h1. Contribute!

* "github.com/wycats/merb-core/tree/master":http://github.com/wycats/merb-core/tree/master
* "merb.lighthouseapp.com":http://merb.lighthouseapp.com
* #merb irc.freenode.net
* "groups.google.com/group/merb":http://groups.google.com/group/merb