= Sinatra

Sinatra a DSL for quickly creating web-applications in Ruby with minimal effort.

= Sample app:

  # myapp.rb

  require 'rubygems'
  require 'sinatra'

  get '/' do
    'Hello world!'
  end

Ruby this as <tt>ruby myapp.rb</tt> and view at <tt>http://localhost:4567</tt>

= RESTful

  get '/' do
    .. show things ..
  end
  
  post '/' do
    .. create something ..
  end
  
  put '/' do
    .. update something ..
  end
  
  delete '/' do
    .. annihilate something ..
  end

= Views (if you need MVC)

All views are looked up in:

  root
    | - views/
    

== Templates
  
=== Haml/Sass

  get '/' do
    haml :index
  end
  
This will render <tt>./views/index.haml</tt>

=== Inline

  get '/' do
    haml '%div.title Hello World'
  end
  
This will render the inlined template string

=== Accessing Variables

Templates are rendered in the context the current Sinatra::EventContext.  This means you get all instance/class variables and methods it has access to.

  get '/:id' do
    @foo = Foo.find(params[:id])
    haml '%h1== @foo.name'
  end

Send local objects like:

  get '/:id' do
    localvar = Foo.find(params[:id])
    haml '%h1== localvar.name', :locals => { :localvar => localvar }
  end
  
This is more ideal for rendering templates as partials from within templates

=== Erb

This works like Haml except you use <tt>erb</tt> instead of <tt>haml</tt>

=== Builder

See Sinatra::Builder

= Helpers

It is ill-advised to create helpers on (main).  Use the handy <tt>helpers</tt> to install helper methods on Sinatra::EventContext for use inside events and templates.

Example:

  helpers do
    
    def bar(name)
      "#{name}bar"
    end
    
  end

= Before filters

  before do
    .. this code will run before each event ..
  end
  
= Halt!

To immediately stop a request during a before filter or event use:
  
  throw :halt
  
=== Variations

Set the body to the result of a helper method

  throw :halt, :helper_method
  
Set the body to the result of a helper method after sending it parameters from the local scope
  
  throw :halt, [:helper_method, foo, bar]
    
Set the body to a simple string

  throw :halt, 'this will be the body'
  
Set status then the body

  throw :halt, [401, 'go away!']
  
Set the status then call a helper method with params from local scope

  throw :halt, [401, [:helper_method, foo, bar]]

Run a proc inside the Sinatra::EventContext instance and set the body to the result

  throw :halt, lambda { puts 'In a proc!'; 'I just wrote to $stdout!' }

Create you own to_result

  class MyResultObject
    def to_result(event_context, *args)
      event_context.body = 'This will be the body!
    end
  end
  
  get '/' do
    throw :halt, MyResultObject.new
  end

Get the gist?  If you want more fun with this then checkout <tt>to_result</tt> on Array, Symbol, Fixnum, NilClass.