= Sinatra

Sinatra is 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

Run with <tt>ruby myapp.rb</tt> and view at <tt>http://localhost:4567</tt>

== HTTP Methods

  get '/' do
    .. show things ..
  end

  post '/' do
    .. create something ..
  end

  put '/' do
    .. update something ..
  end

  delete '/' do
    .. annihilate something ..
  end

  head '/' do

  end

NOTE: <tt>put</tt> and <tt>delete</tt> are also triggered when a
<tt>_method</tt> parameter is set to PUT or DELETE and the HTTP request method
is POST

== Routes

Routes are matched based on the order of declaration. The first route that
matches the request is invoked.

Simple:

  get '/hi' do
    ...
  end

Named parameters:

  get '/:name' do
    # matches /sinatra and the like and sets params[:name]
  end

Splat parameters:

  get '/say/*/to/*' do
    # matches /say/hello/to/world
    params["splat"] # => ["hello", "world"]
  end

  get '/download/*.*' do
    # matches /download/path/to/file.xml
    params["splat"] # => ["path/to/file", "xml"]
  end

User agent matching:

  get '/foo', :agent => /Songbird (\d\.\d)[\d\/]*?/ do
    "You're using Songbird version #{params[:agent][0]}"
  end

  get '/foo' do
    # matches non-songbird browsers
  end

= Static files

Put all of your static content in the ./public directory

  root
    \ public

If a file exists that maps to the REQUEST_PATH then it is served and the
request ends. Otherwise, Sinatra will look for an event that matches the
path.

== Views

Views are searched for in a "views" directory in the same location as
your main application.

=== Haml Templates

  get '/' do
    haml :index
  end

Renders <tt>./views/index.haml</tt>.

=== Erb

  get '/' do
    erb :index
  end

Renders <tt>./views/index.erb</tt>

=== Builder

See Sinatra::Builder

=== Sass

  get '/stylesheet.css' do
    content_type 'text/css', :charset => 'utf-8'
    sass :stylesheet
  end

Renders <tt>./views/stylesheet.sass</tt>.

=== Inline Templates

  get '/' do
    haml '%div.title Hello World'
  end

Renders the inlined template string.

=== Accessing Variables

Templates are evaluated within the Sinatra::EventContext instance
used to evaluate event blocks. Instance variables set in event
blocks can be accessed direcly in views:

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

Or, specify an explicit Hash of local variables:

  get '/:id' do
    foo = Foo.find(params[:id])
    haml '%h1== foo.name', :locals => { :foo => foo }
  end

This is typically used when rendering templates as partials from within
other templates.

=== In-file Templates

Templates may be defined at the end of the source file:

  get '/' do
    haml :index
  end

  use_in_file_templates!

  __END__

  @@ layout
  X
  = yield
  X

  @@ index
  %div.title Hello world!!!!!

It's also possible to define named templates using the 

  template :layout do
    "X\n=yield\nX"
  end

  template :index do
    '%div.title Hello World!'
  end

  get '/' do
    haml :index
  end

== Helpers

The top-level <tt>helpers</tt> method takes a block and extends all
EventContext instances with the methods defined:

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

  get '/:name' do
    bar(params[:name])
  end

== Filters

These are run in Sinatra::EventContext before every event.

  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

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.

== Configuration and Reloading

Sinatra supports multiple environments and re-loading.  Re-loading happens on
every request when in :development.  Wrap your configurations in
<tt>configure</tt> (i.e. Database connections, Constants, etc.) to protect
them from re-loading and to only work in certain environments.

All environments:

  configure do

  end

Production

  configure :production do

  end

Two at a time:

  configure :production, :test do

  end

This is also really nifty for error handling.

= Error handling

== Not Found

Remember:  These are run inside the Sinatra::EventContext which means you get
all the goodies is has to offer (i.e. haml, erb, :halt, etc.)

Whenever NotFound is raised this will be called

  not_found do
    'This is nowhere to be found'
  end

== Error

By default +error+ will catch Sinatra::ServerError

Sinatra will pass you the error via the 'sinatra.error' in request.env

  error do
    'Sorry there was a nasty error - ' + request.env['sinatra.error'].name
  end

Custom error mapping:

  error MyCustomError do
    'So what happened was...' + request.env['sinatra.error'].message
  end

then if this happens:

  get '/' do
    raise MyCustomError, 'something bad'
  end

you gets this:

  So what happened was... something bad

one guess what this does ;)

  not_found do
    'I have no clue what you're looking for'
  end

Because Sinatra gives you a default <tt>not_found</tt> and <tt>error</tt> do
:production that are secure.  If you want to customize only for :production
but want to keep the friendly helper screens for :development then do this:

  configure :production do

    not_found do
      "We're so sorry, but we don't what this is"
    end

    error do
      "Something really nasty happened.  We're on it!"
    end

  end

== Mime types

When using send_file or static files you may have mime types Sinatra doesn't
understand.  Use +mime+ in those cases.

  mime :foo, 'text/foo'

== Rack Middleware

Sinatra rides on Rack[http://rack.rubyforge.org/], a minimal standard
interface for Ruby web frameworks. One of Rack's most interesting capabilities
for application developers is support for "middleware" -- components that sit
between the server and your application monitoring and/or manipulating the
HTTP request/response to provide various types of common functionality.
What's more, middleware is portable between web frameworks, so middleware
components developed under, e.g., Merb, can be used with Sinatra and vice
versa.

Sinatra makes building Rack middleware pipelines a cinch via a top-level +use+
method:

  require 'sinatra'
  require 'my_custom_middleware'

  use Rack::Lint
  use MyCustomMiddleware

  get '/hello' do
    'Hello World'
  end

The semantics of +use+ are identical to those defined for the
Rack::Builder[http://rack.rubyforge.org/doc/classes/Rack/Builder.html] DSL
(most frequently used from rackup files). For example, the +use+ method
accepts multiple/variable args as well as blocks:

  use Rack::Auth::Basic do |username, password|
    username == 'admin' && password == 'secret'
  end

Rack is distributed with a variety of standard middleware for logging,
debugging, URL routing, authentication, and session handling. Sinatra uses
many of of these components automatically based on configuration so you
typically don't have to +use+ them explicitly.

== Testing

=== Methods

  get_it path, params
  get_it path, params.merge(:env => { 'HTTP_HOST' => 'www.sinatrarb.com' }) or
  get_it path, params.merge(:env => { :host => 'www.sinatrarb.com' })

RESTful:

  post_it '/foo', '<myxml></myxml>', 'HTTP_ACCEPT' => 'application/xml'

also works with:

  get_it, post_it, put_it, delete_it, head_it

=== Test/Unit

  require 'my_sinatra_app'
  require 'sinatra/test/unit'

  class MyAppTest < Test::Unit::TestCase

    def test_my_default
      get_it '/'
      assert_equal 'My Default Page!', @response.body
    end

    def test_with_agent
      get_it '/', :agent => 'Songbird'
      assert_equal 'You're in Songbird!', @response.body
    end

    ...

  end

=== Specs

  require 'my_sinatra_app'
  require 'sinatra/test/spec'

  context 'My app'

    should "show a default page" do
      get_it '/'
      should.be.ok
      body.should.equal 'My Default Page!'
    end
    ...

  end

=== Test Helpers

See Sinatra::Test::Methods

== Command line

Run your sinatra file like:

  ruby myapp.rb [options]

Options are:

  -h # help
  -p # set the port (default is 4567)
  -e # set the environment (default is development)
  -x # turn on the mutex lock (default is off)

== Contribute

  cd where/you/keep/your/projects
  git clone git://github.com/bmizerany/sinatra.git
  cd your_project
  ln -s ../sinatra/

At the top of your sinatra.rb file:

  $:.unshift File.dirname(__FILE__) + '/sinatra/lib'
  require 'sinatra'

  get '/about' do
    "I'm running on Version " + Sinatra::VERSION
  end