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<div class='toc'>
	<ol class='level-1'>
		<li><a href='#Routes'>Routes</a></li>
		<ol class='level-2'>
			<li><a href='#Conditions'>Conditions</a></li>
			<li><a href='#Return%20Values'>Return Values</a></li>
			<li><a href='#Custom%20Route%20Matchers'>Custom Route Matchers</a></li>
		<li><a href='#Static%20Files'>Static Files</a></li>
		<li><a href='#Views%20/%20Templates'>Views / Templates</a></li>
		<ol class='level-2'>
			<li><a href='#Available%20Template%20Languages'>Available Template Languages</a></li>
			<li><a href='#Haml%20Templates'>Haml Templates</a></li>
			<li><a href='#Erb%20Templates'>Erb Templates</a></li>
			<li><a href='#Builder%20Templates'>Builder Templates</a></li>
			<li><a href='#Nokogiri%20Templates'>Nokogiri Templates</a></li>
			<li><a href='#Sass%20Templates'>Sass Templates</a></li>
			<li><a href='#SCSS%20Templates'>SCSS Templates</a></li>
			<li><a href='#Less%20Templates'>Less Templates</a></li>
			<li><a href='#Liquid%20Templates'>Liquid Templates</a></li>
			<li><a href='#Markdown%20Templates'>Markdown Templates</a></li>
			<li><a href='#Textile%20Templates'>Textile Templates</a></li>
			<li><a href='#RDoc%20Templates'>RDoc Templates</a></li>
			<li><a href='#Radius%20Templates'>Radius Templates</a></li>
			<li><a href='#Markaby%20Templates'>Markaby Templates</a></li>
			<li><a href='#Slim%20Templates'>Slim Templates</a></li>
			<li><a href='#Creole%20Templates'>Creole Templates</a></li>
			<li><a href='#CoffeeScript%20Templates'>CoffeeScript Templates</a></li>
			<li><a href='#Embedded%20Templates'>Embedded Templates</a></li>
			<li><a href='#Accessing%20Variables%20in%20Templates'>Accessing Variables in Templates</a></li>
			<li><a href='#Inline%20Templates'>Inline Templates</a></li>
			<li><a href='#Named%20Templates'>Named Templates</a></li>
			<li><a href='#Associating%20File%20Extensions'>Associating File Extensions</a></li>
			<li><a href='#Adding%20Your%20Own%20Template%20Engine'>Adding Your Own Template Engine</a></li>
		<li><a href='#Filters'>Filters</a></li>
		<li><a href='#Helpers'>Helpers</a></li>
		<ol class='level-2'>
			<li><a href='#Using%20Sessions'>Using Sessions</a></li>
			<li><a href='#Halting'>Halting</a></li>
			<li><a href='#Passing'>Passing</a></li>
			<li><a href='#Triggering%20Another%20Route'>Triggering Another Route</a></li>
			<li><a href='#Setting%20Body,%20Status%20Code%20and%20Headers'>Setting Body, Status Code and Headers</a></li>
			<li><a href='#Streaming%20Responses'>Streaming Responses</a></li>
			<li><a href='#Logging'>Logging</a></li>
			<li><a href='#Mime%20Types'>Mime Types</a></li>
			<li><a href='#Generating%20URLs'>Generating URLs</a></li>
			<li><a href='#Browser%20Redirect'>Browser Redirect</a></li>
			<li><a href='#Cache%20Control'>Cache Control</a></li>
			<li><a href='#Sending%20Files'>Sending Files</a></li>
			<li><a href='#Accessing%20the%20Request%20Object'>Accessing the Request Object</a></li>
			<li><a href='#Attachments'>Attachments</a></li>
			<li><a href='#Dealing%20with%20Date%20and%20Time'>Dealing with Date and Time</a></li>
			<li><a href='#Looking%20Up%20Template%20Files'>Looking Up Template Files</a></li>
		<li><a href='#Configuration'>Configuration</a></li>
		<ol class='level-2'>
			<li><a href='#Configuring%20attack%20protection'>Configuring attack protection</a></li>
			<li><a href='#Available%20Settings'>Available Settings</a></li>
		<li><a href='#Environments'>Environments</a></li>
		<li><a href='#Error%20Handling'>Error Handling</a></li>
		<ol class='level-2'>
			<li><a href='#Not%20Found'>Not Found</a></li>
			<li><a href='#Error'>Error</a></li>
		<li><a href='#Rack%20Middleware'>Rack Middleware</a></li>
		<li><a href='#Testing'>Testing</a></li>
		<li><a href='#Sinatra::Base%20-%20Middleware,%20Libraries,%20and%20Modular%20Apps'>Sinatra::Base - Middleware, Libraries, and Modular Apps</a></li>
		<ol class='level-2'>
			<li><a href='#Modular%20vs.%20Classic%20Style'>Modular vs. Classic Style</a></li>
			<li><a href='#Serving%20a%20Modular%20Application'>Serving a Modular Application</a></li>
			<li><a href=''>Using a Classic Style Application with a</a></li>
			<li><a href=''>When to use a</a></li>
			<li><a href='#Using%20Sinatra%20as%20Middleware'>Using Sinatra as Middleware</a></li>
			<li><a href='#Dynamic%20Application%20Creation'>Dynamic Application Creation</a></li>
		<li><a href='#Scopes%20and%20Binding'>Scopes and Binding</a></li>
		<ol class='level-2'>
			<li><a href='#Application/Class%20Scope'>Application/Class Scope</a></li>
			<li><a href='#Request/Instance%20Scope'>Request/Instance Scope</a></li>
			<li><a href='#Delegation%20Scope'>Delegation Scope</a></li>
		<li><a href='#Command%20Line'>Command Line</a></li>
		<li><a href='#Requirement'>Requirement</a></li>
		<li><a href='#The%20Bleeding%20Edge'>The Bleeding Edge</a></li>
		<ol class='level-2'>
			<li><a href='#With%20Bundler'>With Bundler</a></li>
			<li><a href='#Roll%20Your%20Own'>Roll Your Own</a></li>
			<li><a href='#Install%20Globally'>Install Globally</a></li>
		<li><a href='#Versioning'>Versioning</a></li>
		<li><a href='#Further%20Reading'>Further Reading</a></li>

<p>Sinatra is a DSL for quickly creating web applications in Ruby with minimal

<pre># myapp.rb
require 'sinatra'

get '/' do
  'Hello world!'

<p>Install the gem and run with:</p>

<pre>gem install sinatra
ruby -rubygems myapp.rb</pre>

<p>View at: <a href="http://localhost:4567">localhost:4567</a></p>

<p>It is recommended to also run <tt>gem install thin</tt>, which Sinatra will
pick up if available.</p>

<a name='Routes'></a>

<p>In Sinatra, a route is an HTTP method paired with a URL-matching pattern.
Each route is associated with a block:</p>

<pre>get '/' do
  .. show something ..

post '/' do
  .. create something ..

put '/' do
  .. replace something ..

patch '/' do
  .. modify something ..

delete '/' do
  .. annihilate something ..

options '/' do
  .. appease something ..

<p>Routes are matched in the order they are defined. The first route that
matches the request is invoked.</p>

<p>Route patterns may include named parameters, accessible via the
<tt>params</tt> hash:</p>

<pre>get '/hello/:name' do
  # matches &quot;GET /hello/foo&quot; and &quot;GET /hello/bar&quot;
  # params[:name] is 'foo' or 'bar'
  &quot;Hello #{params[:name]}!&quot;

<p>You can also access named parameters via block parameters:</p>

<pre>get '/hello/:name' do |n|
  &quot;Hello #{n}!&quot;

<p>Route patterns may also include splat (or wildcard) parameters, accessible
via the <tt>params[:splat]</tt> array:</p>

<pre>get '/say/*/to/*' do
  # matches /say/hello/to/world
  params[:splat] # =&gt; [&quot;hello&quot;, &quot;world&quot;]

get '/download/*.*' do
  # matches /download/path/to/file.xml
  params[:splat] # =&gt; [&quot;path/to/file&quot;, &quot;xml&quot;]

<p>Or with block parameters:</p>

<pre>get '/download/*.*' do |path, ext|
  [path, ext] # =&gt; [&quot;path/to/file&quot;, &quot;xml&quot;]

<p>Route matching with Regular Expressions:</p>

<pre>get %r{/hello/([\w]+)} do
  &quot;Hello, #{params[:captures].first}!&quot;

<p>Or with a block parameter:</p>

<pre>get %r{/hello/([\w]+)} do |c|
  &quot;Hello, #{c}!&quot;

<p>Route patterns may have optional parameters:</p>

<pre>get '/posts.?:format?' do
  # matches &quot;GET /posts&quot; and any extension &quot;GET /posts.json&quot;, &quot;GET /posts.xml&quot; etc.

<p>By the way, unless you disable the path traversal attack protection (see
below), the request path might be modified before matching against your

<a name='Conditions'></a>

<p>Routes may include a variety of matching conditions, such as the user

<pre>get '/foo', :agent =&gt; /Songbird (\d\.\d)[\d\/]*?/ do
  &quot;You're using Songbird version #{params[:agent][0]}&quot;

get '/foo' do
  # Matches non-songbird browsers

<p>Other available conditions are <tt>host_name</tt> and <tt>provides</tt>:</p>

<pre>get '/', :host_name =&gt; /^admin\./ do
  &quot;Admin Area, Access denied!&quot;

get '/', :provides =&gt; 'html' do
  haml :index

get '/', :provides =&gt; ['rss', 'atom', 'xml'] do
  builder :feed

<p>You can easily define your own conditions:</p>

<pre>set(:probability) { |value| condition { rand &lt;= value } }

get '/win_a_car', :probability =&gt; 0.1 do
  &quot;You won!&quot;

get '/win_a_car' do
  &quot;Sorry, you lost.&quot;

<p>For a condition that takes multiple values use a splat:</p>

<pre>set(:auth) do |*roles|   # &lt;- notice the splat here
  condition do
    unless logged_in? &amp;&amp; roles.any? {|role| current_user.in_role? role }
      redirect &quot;/login/&quot;, 303

get &quot;/my/account/&quot;, :auth =&gt; [:user, :admin] do
  &quot;Your Account Details&quot;

get &quot;/only/admin/&quot;, :auth =&gt; :admin do
  &quot;Only admins are allowed here!&quot;

<a name='Return%20Values'></a>
<h3>Return Values</h3>

<p>The return value of a route block determines at least the response body
passed on to the HTTP client, or at least the next middleware in the Rack
stack. Most commonly, this is a string, as in the above examples. But other
values are also accepted.</p>

<p>You can return any object that would either be a valid Rack response, Rack
body object or HTTP status code:</p>
<p>An Array with three elements: <tt>[status (Fixnum), headers (Hash),
response body (responds to #each)]</tt></p>
<p>An Array with two elements: <tt>[status (Fixnum), response body (responds
to #each)]</tt></p>
<p>An object that responds to <tt>#each</tt> and passes nothing but strings to
the given block</p>
<p>A Fixnum representing the status code</p>

<p>That way we can, for instance, easily implement a streaming example:</p>

<pre>class Stream
  def each
    100.times { |i| yield &quot;#{i}\n&quot; }

get('/') { }</pre>

<p>You can also use the <tt>stream</tt> helper method (described below) to
reduce boiler plate and embed the streaming logic in the route.</p>

<a name='Custom%20Route%20Matchers'></a>
<h3>Custom Route Matchers</h3>

<p>As shown above, Sinatra ships with built-in support for using String
patterns and regular expressions as route matches. However, it does not
stop there. You can easily define your own matchers:</p>

<pre>class AllButPattern
  Match =

  def initialize(except)
    @except   = except
    @captures =[])

  def match(str)
    @captures unless @except === str

def all_but(pattern)

get all_but(&quot;/index&quot;) do
  # ...

<p>Note that the above example might be over-engineered, as it can also be
expressed as:</p>

<pre>get // do
  pass if request.path_info == &quot;/index&quot;
  # ...

<p>Or, using negative look ahead:</p>

<pre>get %r{^(?!/index$)} do
  # ...

<a name='Static%20Files'></a>
<h2>Static Files</h2>

<p>Static files are served from the <tt>./public</tt> directory. You can
specify a different location by setting the <tt>:public_folder</tt> option:</p>

<pre>set :public_folder, File.dirname(__FILE__) + '/static'</pre>

<p>Note that the public directory name is not included in the URL. A file
<tt>./public/css/style.css</tt> is made available as

<p>Use the <tt>:static_cache_control</tt> setting (see below) to add
<tt>Cache-Control</tt> header info.</p>

<a name='Views%20/%20Templates'></a>
<h2>Views / Templates</h2>

<p>Each template language is exposed via its own rendering method. These
methods simply return a string:</p>

<pre>get '/' do
  erb :index

<p>This renders <tt>views/index.erb</tt>.</p>

<p>Instead of a template name, you can also just pass in the template content

<pre>get '/' do
  code = &quot;&lt;%= %&gt;&quot;
  erb code

<p>Templates take a second argument, the options hash:</p>

<pre>get '/' do
  erb :index, :layout =&gt; :post

<p>This will render <tt>views/index.erb</tt> embedded in the
<tt>views/post.erb</tt> (default is <tt>views/layout.erb</tt>, if it

<p>Any options not understood by Sinatra will be passed on to the template

<pre>get '/' do
  haml :index, :format =&gt; :html5

<p>You can also set options per template language in general:</p>

<pre>set :haml, :format =&gt; :html5

get '/' do
  haml :index

<p>Options passed to the render method override options set via <tt>set</tt>.</p>

<p>Available Options:</p>
<dl class="rdoc-list"><dt>locals</dt>
<p>List of locals passed to the document. Handy with partials. Example:
<tt>erb &quot;&lt;%= foo %&gt;&quot;, :locals =&gt; {:foo =&gt;
<p>String encoding to use if uncertain. Defaults to
<p>Views folder to load templates from. Defaults to <tt>settings.views</tt>.</p>
<p>Whether to use a layout (<tt>true</tt> or <tt>false</tt>), if it's a
Symbol, specifies what template to use. Example: <tt>erb :index, :layout
=&gt; !request.xhr?</tt></p>
<p>Content-Type the template produces, default depends on template language.</p>
<p>Scope to render template under. Defaults to the application instance. If
you change this, instance variables and helper methods will not be
<p>Template engine to use for rendering the layout. Useful for languages that
do not support layouts otherwise. Defaults to the engine used for the
template. Example: <tt>set :rdoc, :layout_engine =&gt; :erb</tt></p>

<p>Templates are assumed to be located directly under the <tt>./views</tt>
directory. To use a different views directory:</p>

<pre>set :views, settings.root + '/templates'</pre>

<p>One important thing to remember is that you always have to reference
templates with symbols, even if they're in a subdirectory (in this case,
use <tt>:'subdir/template'</tt>). You must use a symbol because otherwise
rendering methods will render any strings passed to them directly.</p>

<a name='Available%20Template%20Languages'></a>
<h3>Available Template Languages</h3>

<p>Some languages have multiple implementations. To specify what
implementation to use (and to be thread-safe), you should simply require it

<pre>require 'rdiscount' # or require 'bluecloth'
get('/') { markdown :index }</pre>

<a name='Haml%20Templates'></a>
<h3>Haml Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">haml</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>haml :index, :format =&gt; :html5</tt></p>

<a name='Erb%20Templates'></a>
<h3>Erb Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">erubis</a> or erb (included in
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
<p><tt>.erb</tt>, <tt>.rhtml</tt> or <tt>.erubis</tt> (Erubis only)</p>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>erb :index</tt></p>

<a name='Builder%20Templates'></a>
<h3>Builder Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">builder</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>builder { |xml| xml.em &quot;hi&quot; }</tt></p>

<p>It also takes a block for inline templates (see example).</p>

<a name='Nokogiri%20Templates'></a>
<h3>Nokogiri Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">nokogiri</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>nokogiri { |xml| xml.em &quot;hi&quot; }</tt></p>

<p>It also takes a block for inline templates (see example).</p>

<a name='Sass%20Templates'></a>
<h3>Sass Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">sass</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>sass :stylesheet, :style =&gt; :expanded</tt></p>

<a name='SCSS%20Templates'></a>
<h3>SCSS Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">sass</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>scss :stylesheet, :style =&gt; :expanded</tt></p>

<a name='Less%20Templates'></a>
<h3>Less Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">less</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>less :stylesheet</tt></p>

<a name='Liquid%20Templates'></a>
<h3>Liquid Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">liquid</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>liquid :index, :locals =&gt; { :key =&gt; 'value' }</tt></p>

<p>Since you cannot call Ruby methods (except for <tt>yield</tt>) from a
Liquid template, you almost always want to pass locals to it.</p>

<a name='Markdown%20Templates'></a>
<h3>Markdown Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">rdiscount</a>, <a
href="">redcarpet</a>, <a
href="">bluecloth</a>, <a
href="">kramdown</a> <b>or</b> <a
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
<p><tt>.markdown</tt>, <tt>.mkd</tt> and <tt>.md</tt></p>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>markdown :index, :layout_engine =&gt; :erb</tt></p>

<p>It is not possible to call methods from markdown, nor to pass locals to it.
You therefore will usually use it in combination with another rendering

<pre>erb :overview, :locals =&gt; { :text =&gt; markdown(:introduction) }</pre>

<p>Note that you may also call the <tt>markdown</tt> method from within other

<pre>%h1 Hello From Haml!
%p= markdown(:greetings)</pre>

<p>Since you cannot call Ruby from Markdown, you cannot use layouts written in
Markdown. However, it is possible to use another rendering engine for the
template than for the layout by passing the <tt>:layout_engine</tt> option.</p>

<a name='Textile%20Templates'></a>
<h3>Textile Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">RedCloth</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>textile :index, :layout_engine =&gt; :erb</tt></p>

<p>It is not possible to call methods from textile, nor to pass locals to it.
You therefore will usually use it in combination with another rendering

<pre>erb :overview, :locals =&gt; { :text =&gt; textile(:introduction) }</pre>

<p>Note that you may also call the <tt>textile</tt> method from within other

<pre>%h1 Hello From Haml!
%p= textile(:greetings)</pre>

<p>Since you cannot call Ruby from Textile, you cannot use layouts written in
Textile. However, it is possible to use another rendering engine for the
template than for the layout by passing the <tt>:layout_engine</tt> option.</p>

<a name='RDoc%20Templates'></a>
<h3>RDoc Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">rdoc</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>rdoc :README, :layout_engine =&gt; :erb</tt></p>

<p>It is not possible to call methods from rdoc, nor to pass locals to it. You
therefore will usually use it in combination with another rendering engine:</p>

<pre>erb :overview, :locals =&gt; { :text =&gt; rdoc(:introduction) }</pre>

<p>Note that you may also call the <tt>rdoc</tt> method from within other

<pre>%h1 Hello From Haml!
%p= rdoc(:greetings)</pre>

<p>Since you cannot call Ruby from RDoc, you cannot use layouts written in
RDoc. However, it is possible to use another rendering engine for the
template than for the layout by passing the <tt>:layout_engine</tt> option.</p>

<a name='Radius%20Templates'></a>
<h3>Radius Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">radius</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>radius :index, :locals =&gt; { :key =&gt; 'value' }</tt></p>

<p>Since you cannot call Ruby methods directly from a Radius template, you
almost always want to pass locals to it.</p>

<a name='Markaby%20Templates'></a>
<h3>Markaby Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">markaby</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>markaby { h1 &quot;Welcome!&quot; }</tt></p>

<p>It also takes a block for inline templates (see example).</p>

<a name='Slim%20Templates'></a>
<h3>Slim Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">slim</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>slim :index</tt></p>

<a name='Creole%20Templates'></a>
<h3>Creole Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">creole</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>creole :wiki, :layout_engine =&gt; :erb</tt></p>

<p>It is not possible to call methods from creole, nor to pass locals to it.
You therefore will usually use it in combination with another rendering

<pre>erb :overview, :locals =&gt; { :text =&gt; creole(:introduction) }</pre>

<p>Note that you may also call the <tt>creole</tt> method from within other

<pre>%h1 Hello From Haml!
%p= creole(:greetings)</pre>

<p>Since you cannot call Ruby from Creole, you cannot use layouts written in
Creole. However, it is possible to use another rendering engine for the
template than for the layout by passing the <tt>:layout_engine</tt> option.</p>

<a name='CoffeeScript%20Templates'></a>
<h3>CoffeeScript Templates</h3>
<table class="rdoc-list"><tr><td class="rdoc-term"><p>Dependency</p></td>
<p><a href="">coffee-script</a> and
a <a
to execute javascript</a></p>
</td></tr><tr><td class="rdoc-term"><p>File Extensions</p></td>
</td></tr><tr><td class="rdoc-term"><p>Example</p></td>
<p><tt>coffee :index</tt></p>

<a name='Embedded%20Templates'></a>
<h3>Embedded Templates</h3>

<pre>get '/' do
  haml '%div.title Hello World'

<p>Renders the embedded template string.</p>

<a name='Accessing%20Variables%20in%20Templates'></a>
<h3>Accessing Variables in Templates</h3>

<p>Templates are evaluated within the same context as route handlers. Instance
variables set in route handlers are directly accessible by templates:</p>

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

<p>Or, specify an explicit Hash of local variables:</p>

<pre>get '/:id' do
  foo = Foo.find(params[:id])
  haml '%h1=', :locals =&gt; { :bar =&gt; foo }

<p>This is typically used when rendering templates as partials from within
other templates.</p>

<a name='Inline%20Templates'></a>
<h3>Inline Templates</h3>

<p>Templates may be defined at the end of the source file:</p>

<pre>require 'sinatra'

get '/' do
  haml :index


@@ layout
  = yield

@@ index
%div.title Hello world.</pre>

<p>NOTE: Inline templates defined in the source file that requires sinatra are
automatically loaded. Call <tt>enable :inline_templates</tt> explicitly if
you have inline templates in other source files.</p>

<a name='Named%20Templates'></a>
<h3>Named Templates</h3>

<p>Templates may also be defined using the top-level <tt>template</tt> method:</p>

<pre>template :layout do
  &quot;%html\n  =yield\n&quot;

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

get '/' do
  haml :index

<p>If a template named "layout" exists, it will be used each time a template
is rendered. You can individually disable layouts by passing <tt>:layout
=&gt; false</tt> or disable them by default via <tt>set :haml, :layout
=&gt; false</tt>:</p>

<pre>get '/' do
  haml :index, :layout =&gt; !request.xhr?

<a name='Associating%20File%20Extensions'></a>
<h3>Associating File Extensions</h3>

<p>To associate a file extension with a template engine, use
<tt>Tilt.register</tt>. For instance, if you like to use the file extension
<tt>tt</tt> for Textile templates, you can do the following:</p>

<pre>Tilt.register :tt, Tilt[:textile]</pre>

<a name='Adding%20Your%20Own%20Template%20Engine'></a>
<h3>Adding Your Own Template Engine</h3>

<p>First, register your engine with Tilt, then create a rendering method:</p>

<pre>Tilt.register :myat, MyAwesomeTemplateEngine

helpers do
  def myat(*args) render(:myat, *args) end

get '/' do
  myat :index

<p>Renders <tt>./views/index.myat</tt>. See <a
href=""></a> to
learn more about Tilt.</p>

<a name='Filters'></a>

<p>Before filters are evaluated before each request within the same context as
the routes will be and can modify the request and response. Instance
variables set in filters are accessible by routes and templates:</p>

<pre>before do
  @note = 'Hi!'
  request.path_info = '/foo/bar/baz'

get '/foo/*' do
  @note #=&gt; 'Hi!'
  params[:splat] #=&gt; 'bar/baz'

<p>After filters are evaluated after each request within the same context and
can also modify the request and response. Instance variables set in before
filters and routes are accessible by after filters:</p>

<pre>after do
  puts response.status

<p>Note: Unless you use the <tt>body</tt> method rather than just returning a
String from the routes, the body will not yet be available in the after
filter, since it is generated later on.</p>

<p>Filters optionally take a pattern, causing them to be evaluated only if the
request path matches that pattern:</p>

<pre>before '/protected/*' do

after '/create/:slug' do |slug|
  session[:last_slug] = slug

<p>Like routes, filters also take conditions:</p>

<pre>before :agent =&gt; /Songbird/ do
  # ...

after '/blog/*', :host_name =&gt; '' do
  # ...

<a name='Helpers'></a>

<p>Use the top-level <tt>helpers</tt> method to define helper methods for use
in route handlers and templates:</p>

<pre>helpers do
  def bar(name)

get '/:name' do

<p>Alternatively, helper methods can be separately defined in a module:</p>

<pre>module FooUtils
  def foo(name) &quot;#{name}foo&quot; end

module BarUtils
  def bar(name) &quot;#{name}bar&quot; end

helpers FooUtils, BarUtils</pre>

<p>The effect is the same as including the modules in the application class.</p>

<a name='Using%20Sessions'></a>
<h3>Using Sessions</h3>

<p>A session is used to keep state during requests. If activated, you have one
session hash per user session:</p>

<pre>enable :sessions

get '/' do
  &quot;value = &quot; &lt;&lt; session[:value].inspect

get '/:value' do
  session[:value] = params[:value]

<p>Note that <tt>enable :sessions</tt> actually stores all data in a cookie.
This might not always be what you want (storing lots of data will increase
your traffic, for instance). You can use any Rack session middleware: in
order to do so, do <b>not</b> call <tt>enable :sessions</tt>, but instead
pull in your middleware of choice as you would any other middleware:</p>

<pre>use Rack::Session::Pool, :expire_after =&gt; 2592000

get '/' do
  &quot;value = &quot; &lt;&lt; session[:value].inspect

get '/:value' do
  session[:value] = params[:value]

<p>To improve security, the session data in the cookie is signed with a
session secret. A random secret is generated for you by Sinatra. However,
since this secret will change with every start of your application, you
might want to set the secret yourself, so all your application instances
share it:</p>

<pre>set :session_secret, 'super secret'</pre>

<p>If you want to configure it further, you may also store a hash with options
in the <tt>sessions</tt> setting:</p>

<pre>set :sessions, :domain =&gt; ''</pre>

<a name='Halting'></a>

<p>To immediately stop a request within a filter or route use:</p>


<p>You can also specify the status when halting:</p>

<pre>halt 410</pre>

<p>Or the body:</p>

<pre>halt 'this will be the body'</pre>

<p>Or both:</p>

<pre>halt 401, 'go away!'</pre>

<p>With headers:</p>

<pre>halt 402, {'Content-Type' =&gt; 'text/plain'}, 'revenge'</pre>

<p>It is of course possible to combine a template with <tt>halt</tt>:</p>

<pre>halt erb(:error)</pre>

<a name='Passing'></a>

<p>A route can punt processing to the next matching route using <tt>pass</tt>:</p>

<pre>get '/guess/:who' do
  pass unless params[:who] == 'Frank'
  'You got me!'

get '/guess/*' do
  'You missed!'

<p>The route block is immediately exited and control continues with the next
matching route. If no matching route is found, a 404 is returned.</p>

<a name='Triggering%20Another%20Route'></a>
<h3>Triggering Another Route</h3>

<p>Sometimes <tt>pass</tt> is not what you want, instead you would like to get
the result of calling another route. Simply use <tt>call</tt> to achieve

<pre>get '/foo' do
  status, headers, body = call env.merge(&quot;PATH_INFO&quot; =&gt; '/bar')
  [status, headers,;:upcase)]

get '/bar' do

<p>Note that in the example above, you would ease testing and increase
performance by simply moving <tt>&quot;bar&quot;</tt> into a helper used by
both <tt>/foo</tt> and <tt>/bar</tt>.</p>

<p>If you want the request to be sent to the same application instance rather
than a duplicate, use <tt>call!</tt> instead of <tt>call</tt>.</p>

<p>Check out the Rack specification if you want to learn more about

<a name='Setting%20Body,%20Status%20Code%20and%20Headers'></a>
<h3>Setting Body, Status Code and Headers</h3>

<p>It is possible and recommended to set the status code and response body
with the return value of the route block. However, in some scenarios you
might want to set the body at an arbitrary point in the execution flow. You
can do so with the <tt>body</tt> helper method. If you do so, you can use
that method from there on to access the body:</p>

<pre>get '/foo' do
  body &quot;bar&quot;

after do
  puts body

<p>It is also possible to pass a block to <tt>body</tt>, which will be
executed by the Rack handler (this can be used to implement streaming, see
"Return Values").</p>

<p>Similar to the body, you can also set the status code and headers:</p>

<pre>get '/foo' do
  status 418
  headers \
    &quot;Allow&quot;   =&gt; &quot;BREW, POST, GET, PROPFIND, WHEN&quot;,
    &quot;Refresh&quot; =&gt; &quot;Refresh: 20;;
  body &quot;I'm a tea pot!&quot;

<p>Like <tt>body</tt>, <tt>headers</tt> and <tt>status</tt> with no arguments
can be used to access their current values.</p>

<a name='Streaming%20Responses'></a>
<h3>Streaming Responses</h3>

<p>Sometimes you want to start sending out data while still generating parts
of the response body. In extreme examples, you want to keep sending data
until the client closes the connection. You can use the <tt>stream</tt>
helper to avoid creating your own wrapper:</p>

<pre>get '/' do
  stream do |out|
    out &lt;&lt; &quot;It's gonna be legen -\n&quot;
    sleep 0.5
    out &lt;&lt; &quot; (wait for it) \n&quot;
    sleep 1
    out &lt;&lt; &quot;- dary!\n&quot;

<p>This allows you to implement streaming APIs, <a
href="">Server Sent Events</a> and can
be used as the basis for <a
href="">WebSockets</a>. It can also
be used to increase throughput if some but not all content depends on a
slow resource.</p>

<p>Note that the streaming behavior, especially the number of concurrent
requests, highly depends on the web server used to serve the application.
Some servers, like WEBRick, might not even support streaming at all. If the
server does not support streaming, the body will be sent all at once after
the block passed to <tt>stream</tt> finishes executing. Streaming does not
work at all with Shotgun.</p>

<p>If the optional parameter is set to <tt>keep_open</tt>, it will not call
<tt>close</tt> on the stream object, allowing you to close it at any later
point in the execution flow. This only works on evented servers, like Thin
and Rainbows. Other servers will still close the stream:</p>

<pre>set :server, :thin
connections = []

get '/' do
  # keep stream open
  stream(:keep_open) { |out| connections &lt;&lt; out }

post '/' do
  # write to all open streams
  connections.each { |out| out &lt;&lt; params[:message] &lt;&lt; &quot;\n&quot; }
  &quot;message sent&quot;

<a name='Logging'></a>

<p>In the request scope, the <tt>logger</tt> helper exposes a <tt>Logger</tt>

<pre>get '/' do &quot;loading data&quot;
  # ...

<p>This logger will automatically take your Rack handler's logging settings
into account. If logging is disabled, this method will return a dummy
object, so you do not have to worry in your routes and filters about it.</p>

<p>Note that logging is only enabled for <tt>Sinatra::Application</tt> by
default, so if you inherit from <tt>Sinatra::Base</tt>, you probably want
to enable it yourself:</p>

<pre>class MyApp &lt; Sinatra::Base
  configure :production, :development do
    enable :logging

<p>To avoid any logging middleware to be set up, set the <tt>logging</tt>
setting to <tt>nil</tt>. However, keep in mind that <tt>logger</tt> will in
that case return <tt>nil</tt>. A common use case is when you want to set
your own logger. Sinatra will use whatever it will find in

<a name='Mime%20Types'></a>
<h3>Mime Types</h3>

<p>When using <tt>send_file</tt> or static files you may have mime types
Sinatra doesn't understand. Use <tt>mime_type</tt> to register them by file

<pre>configure do
  mime_type :foo, 'text/foo'

<p>You can also use it with the <tt>content_type</tt> helper:</p>

<pre>get '/' do
  content_type :foo
  &quot;foo foo foo&quot;

<a name='Generating%20URLs'></a>
<h3>Generating URLs</h3>

<p>For generating URLs you should use the <tt>url</tt> helper method, for
instance, in Haml:</p>

<pre>%a{:href =&gt; url('/foo')} foo</pre>

<p>It takes reverse proxies and Rack routers into account, if present.</p>

<p>This method is also aliased to <tt>to</tt> (see below for an example).</p>

<a name='Browser%20Redirect'></a>
<h3>Browser Redirect</h3>

<p>You can trigger a browser redirect with the <tt>redirect</tt> helper

<pre>get '/foo' do
  redirect to('/bar')

<p>Any additional parameters are handled like arguments passed to

<pre>redirect to('/bar'), 303
redirect '', 'wrong place, buddy'</pre>

<p>You can also easily redirect back to the page the user came from with
<tt>redirect back</tt>:</p>

<pre>get '/foo' do
  &quot;&lt;a href='/bar'&gt;do something&lt;/a&gt;&quot;

get '/bar' do
  redirect back

<p>To pass arguments with a redirect, either add them to the query:</p>

<pre>redirect to('/bar?sum=42')</pre>

<p>Or use a session:</p>

<pre>enable :sessions

get '/foo' do
  session[:secret] = 'foo'
  redirect to('/bar')

get '/bar' do

<a name='Cache%20Control'></a>
<h3>Cache Control</h3>

<p>Setting your headers correctly is the foundation for proper HTTP caching.</p>

<p>You can easily set the Cache-Control header with like this:</p>

<pre>get '/' do
  cache_control :public
  &quot;cache it!&quot;

<p>Pro tip: Set up caching in a before filter:</p>

<pre>before do
  cache_control :public, :must_revalidate, :max_age =&gt; 60

<p>If you are using the <tt>expires</tt> helper to set the corresponding
header, <tt>Cache-Control</tt> will be set automatically for you:</p>

<pre>before do
  expires 500, :public, :must_revalidate

<p>To properly use caches, you should consider using <tt>etag</tt> or
<tt>last_modified</tt>. It is recommended to call those helpers
<b>before</b> doing heavy lifting, as they will immediately flush a
response if the client already has the current version in its cache:</p>

<pre>get '/article/:id' do
  @article = Article.find params[:id]
  last_modified @article.updated_at
  etag @article.sha1
  erb :article

<p>It is also possible to use a <a

<pre>etag @article.sha1, :weak</pre>

<p>These helpers will not do any caching for you, but rather feed the
necessary information to your cache. If you are looking for a quick
reverse-proxy caching solution, try <a

<pre>require &quot;rack/cache&quot;
require &quot;sinatra&quot;

use Rack::Cache

get '/' do
  cache_control :public, :max_age =&gt; 36000
  sleep 5

<p>Use the <tt>:static_cache_control</tt> setting (see below) to add
<tt>Cache-Control</tt> header info to static files.</p>

<p>According to RFC 2616 your application should behave differently if the
If-Match or If-None-Match header is set to <tt>*</tt> depending on whether
the resource requested is already in existence. Sinatra assumes resources
for safe (like get) and idempotent (like put) requests are already in
existence, whereas other resources (for instance for post requests), are
treated as new resources. You can change this behavior by passing in a
<tt>:new_resource</tt> option:</p>

<pre>get '/create' do
  etag '', :new_resource =&gt; true
  erb :new_article

<p>If you still want to use a weak ETag, pass in a <tt>:kind</tt> option:</p>

<pre>etag '', :new_resource =&gt; true, :kind =&gt; :weak</pre>

<a name='Sending%20Files'></a>
<h3>Sending Files</h3>

<p>For sending files, you can use the <tt>send_file</tt> helper method:</p>

<pre>get '/' do
  send_file 'foo.png'

<p>It also takes a couple of options:</p>

<pre>send_file 'foo.png', :type =&gt; :jpg</pre>

<p>The options are:</p>
<dl class="rdoc-list"><dt>filename</dt>
<p>file name, in response, defaults to the real file name.</p>
<p>value for Last-Modified header, defaults to the file's mtime.</p>
<p>content type to use, guessed from the file extension if missing.</p>
<p>used for Content-Disposition, possible values: <tt>nil</tt> (default),
<tt>:attachment</tt> and <tt>:inline</tt></p>
<p>Content-Length header, defaults to file size.</p>

<p>If supported by the Rack handler, other means than streaming from the Ruby
process will be used. If you use this helper method, Sinatra will
automatically handle range requests.</p>

<a name='Accessing%20the%20Request%20Object'></a>
<h3>Accessing the Request Object</h3>

<p>The incoming request object can be accessed from request level (filter,
routes, error handlers) through the <tt>request</tt> method:</p>

<pre># app running on
get '/foo' do
  t = %w[text/css text/html application/javascript]
  request.accept              # ['text/html', '*/*']
  request.accept? 'text/xml'  # true
  request.preferred_type(t)   # 'text/html'
  request.body                # request body sent by the client (see below)
  request.scheme              # &quot;http&quot;
  request.script_name         # &quot;/example&quot;
  request.path_info           # &quot;/foo&quot;
  request.port                # 80
  request.request_method      # &quot;GET&quot;
  request.query_string        # &quot;&quot;
  request.content_length      # length of request.body
  request.media_type          # media type of request.body                # &quot;;
  request.get?                # true (similar methods for other verbs)
  request.form_data?          # false
  request[&quot;SOME_HEADER&quot;]      # value of SOME_HEADER header
  request.referrer            # the referrer of the client or '/'
  request.user_agent          # user agent (used by :agent condition)
  request.cookies             # hash of browser cookies
  request.xhr?                # is this an ajax request?
  request.url                 # &quot;;
  request.path                # &quot;/example/foo&quot;
  request.ip                  # client IP address             # false (would be true over ssl)
  request.forwarded?          # true (if running behind a reverse proxy)
  request.env                 # raw env hash handed in by Rack

<p>Some options, like <tt>script_name</tt> or <tt>path_info</tt>, can also be

<pre>before { request.path_info = &quot;/&quot; }

get &quot;/&quot; do
  &quot;all requests end up here&quot;

<p>The <tt>request.body</tt> is an IO or StringIO object:</p>

<pre>post &quot;/api&quot; do
  request.body.rewind  # in case someone already read it
  data = JSON.parse
  &quot;Hello #{data['name']}!&quot;

<a name='Attachments'></a>

<p>You can use the <tt>attachment</tt> helper to tell the browser the response
should be stored on disk rather than displayed in the browser:</p>

<pre>get '/' do
  &quot;store it!&quot;

<p>You can also pass it a file name:</p>

<pre>get '/' do
  attachment &quot;info.txt&quot;
  &quot;store it!&quot;

<a name='Dealing%20with%20Date%20and%20Time'></a>
<h3>Dealing with Date and Time</h3>

<p>Sinatra offers a <tt>time_for</tt> helper method, which, from the given
value generates a Time object. It is also able to convert
<tt>DateTime</tt>, <tt>Date</tt> and similar classes:</p>

<pre>get '/' do
  pass if &gt; time_for('Dec 23, 2012')
  &quot;still time&quot;

<p>This method is used internally by <tt>expires</tt>, <tt>last_modified</tt>
and akin. You can therefore easily extend the behavior of those methods by
overriding <tt>time_for</tt> in your application:</p>

<pre>helpers do
  def time_for(value)
    case value
    when :yesterday then - 24*60*60
    when :tomorrow  then + 24*60*60
    else super

get '/' do
  last_modified :yesterday
  expires :tomorrow

<a name='Looking%20Up%20Template%20Files'></a>
<h3>Looking Up Template Files</h3>

<p>The <tt>find_template</tt> helper is used to find template files for

<pre>find_template settings.views, 'foo', Tilt[:haml] do |file|
  puts &quot;could be #{file}&quot;

<p>This is not really useful. But it is useful that you can actually override
this method to hook in your own lookup mechanism. For instance, if you want
to be able to use more than one view directory:</p>

<pre>set :views, ['views', 'templates']

helpers do
  def find_template(views, name, engine, &amp;block)
    Array(views).each { |v| super(v, name, engine, &amp;block) }

<p>Another example would be using different directories for different engines:</p>

<pre>set :views, :sass =&gt; 'views/sass', :haml =&gt; 'templates', :default =&gt; 'views'

helpers do
  def find_template(views, name, engine, &amp;block)
    _, folder = views.detect { |k,v| engine == Tilt[k] }
    folder ||= views[:default]
    super(folder, name, engine, &amp;block)

<p>You can also easily wrap this up in an extension and share with others!</p>

<p>Note that <tt>find_template</tt> does not check if the file really exists
but rather calls the given block for all possible paths. This is not a
performance issue, since <tt>render</tt> will use <tt>break</tt> as soon as
a file is found. Also, template locations (and content) will be cached if
you are not running in development mode. You should keep that in mind if
you write a really crazy method.</p>

<a name='Configuration'></a>

<p>Run once, at startup, in any environment:</p>

<pre>configure do
  # setting one option
  set :option, 'value'

  # setting multiple options
  set :a =&gt; 1, :b =&gt; 2

  # same as `set :option, true`
  enable :option

  # same as `set :option, false`
  disable :option

  # you can also have dynamic settings with blocks
  set(:css_dir) { File.join(views, 'css') }

<p>Run only when the environment (RACK_ENV environment variable) is set to

<pre>configure :production do

<p>Run when the environment is set to either <tt>:production</tt> or

<pre>configure :production, :test do

<p>You can access those options via <tt>settings</tt>:</p>

<pre>configure do
  set :foo, 'bar'

get '/' do # =&gt; true  # =&gt; 'bar'

<a name='Configuring%20attack%20protection'></a>
<h3>Configuring attack protection</h3>

<p>Sinatra is using <a
to defend you application against common, opportunistic attacks. You can
easily disable this behavior (which will open your application to tons of
common vulnerabilities):</p>

<pre>disable :protection</pre>

<p>To skip a single defense layer, set <tt>protection</tt> to an options hash:</p>

<pre>set :protection, :except =&gt; :path_traversal</pre>

<p>You can also hand in an array in order to disable a list of protections:</p>

<pre>set :protection, :except =&gt; [:path_traversal, :session_hijacking]</pre>

<a name='Available%20Settings'></a>
<h3>Available Settings</h3>
<dl class="rdoc-list"><dt>absolute_redirects</dt>
<p>If disabled, Sinatra will allow relative redirects, however, Sinatra will
no longer conform with RFC 2616 (HTTP 1.1), which only allows absolute

<p>Enable if your app is running behind a reverse proxy that has not been set
up properly. Note that the <tt>url</tt> helper will still produce absolute
URLs, unless you pass in <tt>false</tt> as second parameter.</p>

<p>Disabled per default.</p>
<p>mime types the <tt>content_type</tt> helper will automatically add the
charset info to.</p>

<p>You should add to it rather than overriding this option:</p>

<pre>settings.add_charsets &lt;&lt; &quot;application/foobar&quot;</pre>
<p>Path to the main application file, used to detect project root, views and
public folder and inline templates.</p>
<p>IP address to bind to (default: Only used for built-in server.</p>
<p>encoding to assume if unknown (defaults to <tt>&quot;utf-8&quot;</tt>).</p>
<p>display errors in the log.</p>
<p>current environment, defaults to <tt>ENV['RACK_ENV']</tt>, or
<tt>&quot;development&quot;</tt> if not available.</p>
<p>use the logger.</p>
<p>Places a lock around every request, only running processing on request per
Ruby process concurrently.</p>

<p>Enabled if your app is not thread-safe. Disabled per default.</p>
<p>use <tt>_method</tt> magic to allow put/delete forms in browsers that don't
support it.</p>
<p>Port to listen on. Only used for built-in server.</p>
<p>Whether or not to insert <tt>request.script_name</tt> into redirects if no
absolute path is given. That way <tt>redirect '/foo'</tt> would behave like
<tt>redirect to('/foo')</tt>. Disabled per default.</p>
<p>Whether or not to enable web attack protections. See protection section
<p>Path to the folder public files are served from. Only used if static file
serving is enabled (see <tt>static</tt> setting below). Inferred from
<tt>app_file</tt> setting if not set.</p>
<p>whether or not to reload templates between requests. Enabled in development
<p>Path to project root folder. Inferred from <tt>app_file</tt> setting if not
<p>raise exceptions (will stop application). Enabled by default when
<tt>environment</tt> is set to <tt>&quot;test&quot;</tt>, disabled
<p>if enabled, Sinatra will handle starting the web server, do not enable if
using rackup or other means.</p>
<p>is the built-in server running now? do not change this setting!</p>
<p>server or list of servers to use for built-in server. defaults to ['thin',
'mongrel', 'webrick'], order indicates priority.</p>
<p>enable cookie based sessions support using <tt>Rack::Session::Cookie</tt>.
See 'Using Sessions' section for more information.</p>
<p>show a stack trace in the browser when an exception happens. Enabled by
default when <tt>environment</tt> is set to
<tt>&quot;development&quot;</tt>, disabled otherwise. Can also be set to
<tt>:after_handler</tt> to trigger app-specified error handling before
showing a stack trace in the browser.</p>
<p>Whether Sinatra should handle serving static files. Disable when using a
Server able to do this on its own. Disabling will boost performance.
Enabled per default in classic style, disabled for modular apps.</p>
<p>When Sinatra is serving static files, set this to add
<tt>Cache-Control</tt> headers to the responses. Uses the
<tt>cache_control</tt> helper. Disabled by default. Use an explicit array
when setting multiple values: <tt>set :static_cache_control, [:public,
:max_age =&gt; 300]</tt></p>
<p>If set to <tt>true</tt>, will tell Thin to use <tt>EventMachine.defer</tt>
for processing the request.</p>
<p>Path to the views folder. Inferred from <tt>app_file</tt> setting if not

<a name='Environments'></a>

<p>There are three predefined <tt>environments</tt>:
<tt>&quot;development&quot;</tt>, <tt>&quot;production&quot;</tt> and
<tt>&quot;test&quot;</tt>. Environments can be set through the
<tt>RACK_ENV</tt> environment variable. The default value is
<tt>&quot;development&quot;</tt>. In this mode, all templates are reloaded
between requests. Special <tt>not_found</tt> and <tt>error</tt> handlers
are installed for this environment so you will see a stack trace in your
browser. In <tt>&quot;production&quot;</tt> and <tt>&quot;test&quot;</tt>
templates are cached by default.</p>

<p>To run different environments use the <tt>-e</tt> option:</p>

<pre>ruby my_app.rb -e [ENVIRONMENT]</pre>

<p>You can use predefined methods: <tt>development?</tt>, <tt>test?</tt> and
<tt>production?</tt> to check which enviroment is currently set.</p>

<a name='Error%20Handling'></a>
<h2>Error Handling</h2>

<p>Error handlers run within the same context as routes and before filters,
which means you get all the goodies it has to offer, like <tt>haml</tt>,
<tt>erb</tt>, <tt>halt</tt>, etc.</p>

<a name='Not%20Found'></a>
<h3>Not Found</h3>

<p>When a <tt>Sinatra::NotFound</tt> exception is raised, or the response's
status code is 404, the <tt>not_found</tt> handler is invoked:</p>

<pre>not_found do
  'This is nowhere to be found.'

<a name='Error'></a>

<p>The <tt>error</tt> handler is invoked any time an exception is raised from
a route block or a filter. The exception object can be obtained from the
<tt>sinatra.error</tt> Rack variable:</p>

<pre>error do
  'Sorry there was a nasty error - ' + env['sinatra.error'].name

<p>Custom errors:</p>

<pre>error MyCustomError do
  'So what happened was...' + env['sinatra.error'].message

<p>Then, if this happens:</p>

<pre>get '/' do
  raise MyCustomError, 'something bad'

<p>You get this:</p>

<pre>So what happened was... something bad</pre>

<p>Alternatively, you can install an error handler for a status code:</p>

<pre>error 403 do
  'Access forbidden'

get '/secret' do

<p>Or a range:</p>

<pre>error 400..510 do

<p>Sinatra installs special <tt>not_found</tt> and <tt>error</tt> handlers
when running under the development environment.</p>

<a name='Rack%20Middleware'></a>
<h2>Rack Middleware</h2>

<p>Sinatra rides on <a href="">Rack</a>, 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.</p>

<p>Sinatra makes building Rack middleware pipelines a cinch via a top-level
<tt>use</tt> method:</p>

<pre>require 'sinatra'
require 'my_custom_middleware'

use Rack::Lint
use MyCustomMiddleware

get '/hello' do
  'Hello World'

<p>The semantics of <tt>use</tt> are identical to those defined for the <a
DSL (most frequently used from rackup files). For example, the <tt>use</tt>
method accepts multiple/variable args as well as blocks:</p>

<pre>use Rack::Auth::Basic do |username, password|
  username == 'admin' &amp;&amp; password == 'secret'

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

<p>You can find useful middleware in <a
href="">rack</a>, <a
href="">rack-contrib</a>, with
<a href="">CodeRack</a> or in the <a
href="">Rack wiki</a>.</p>

<a name='Testing'></a>

<p>Sinatra tests can be written using any Rack-based testing library or
framework. <a
is recommended:</p>

<pre>require 'my_sinatra_app'
require 'test/unit'
require 'rack/test'

class MyAppTest &lt; Test::Unit::TestCase
  include Rack::Test::Methods

  def app

  def test_my_default
    get '/'
    assert_equal 'Hello World!', last_response.body

  def test_with_params
    get '/meet', :name =&gt; 'Frank'
    assert_equal 'Hello Frank!', last_response.body

  def test_with_rack_env
    get '/', {}, 'HTTP_USER_AGENT' =&gt; 'Songbird'
    assert_equal &quot;You're using Songbird!&quot;, last_response.body

<a name='Sinatra::Base%20-%20Middleware,%20Libraries,%20and%20Modular%20Apps'></a>
<h2>Sinatra::Base - Middleware, Libraries, and Modular Apps</h2>

<p>Defining your app at the top-level works well for micro-apps but has
considerable drawbacks when building reusable components such as Rack
middleware, Rails metal, simple libraries with a server component, or even
Sinatra extensions. The top-level DSL pollutes the Object namespace and
assumes a micro-app style configuration (e.g., a single application file,
<tt>./public</tt> and <tt>./views</tt> directories, logging, exception
detail page, etc.). That's where <tt>Sinatra::Base</tt> comes into play:</p>

<pre>require 'sinatra/base'

class MyApp &lt; Sinatra::Base
  set :sessions, true
  set :foo, 'bar'

  get '/' do
    'Hello world!'

<p>The methods available to <tt>Sinatra::Base</tt> subclasses are exactly as
those available via the top-level DSL. Most top-level apps can be converted
to <tt>Sinatra::Base</tt> components with two modifications:</p>
<p>Your file should require <tt>sinatra/base</tt> instead of <tt>sinatra</tt>;
otherwise, all of Sinatra's DSL methods are imported into the main
<p>Put your app's routes, error handlers, filters, and options in a subclass
of <tt>Sinatra::Base</tt>.</p>

<p><tt>Sinatra::Base</tt> is a blank slate. Most options are disabled by
default, including the built-in server. See <a
href="">Options and
Configuration</a> for details on available options and their behavior.</p>

<a name='Modular%20vs.%20Classic%20Style'></a>
<h3>Modular vs. Classic Style</h3>

<p>Contrary to common belief, there is nothing wrong with classic style. If it
suits your application, you do not have to switch to a modular application.</p>

<p>There are only two downsides compared with modular style:</p>
<p>You may only have one Sinatra application per Ruby process. If you plan to
use more, switch to modular style.</p>
<p>Classic style pollutes Object with delegator methods. If you plan to ship
your application in a library/gem, switch to modular style.</p>

<p>There is no reason you cannot mix modular and classic style.</p>

<p>If switching from one style to the other, you should be aware of slightly
different default settings:</p>

<pre>Setting             Classic                 Modular

app_file            file loading sinatra    file subclassing Sinatra::Base
run                 $0 == app_file          false
logging             true                    false
method_override     true                    false
inline_templates    true                    false
static              true                    false</pre>

<a name='Serving%20a%20Modular%20Application'></a>
<h3>Serving a Modular Application</h3>

<p>There are two common options for starting a modular app, actively starting
with <tt>run!</tt>:</p>

<pre># my_app.rb
require 'sinatra/base'

class MyApp &lt; Sinatra::Base
  # ... app code here ...

  # start the server if ruby file executed directly
  run! if app_file == $0

<p>Start with:</p>

<pre>ruby my_app.rb</pre>

<p>Or with a <tt></tt>, which allows using any Rack handler:</p>

require './my_app'
run MyApp</pre>


<pre>rackup -p 4567</pre>

<a name=''></a>
<h3>Using a Classic Style Application with a</h3>

<p>Write your app file:</p>

<pre># app.rb
require 'sinatra'

get '/' do
  'Hello world!'

<p>And a corresponding <tt></tt>:</p>

<pre>require './app'
run Sinatra::Application</pre>

<a name=''></a>
<h3>When to use a</h3>

<p>Good signs you probably want to use a <tt></tt>:</p>
<p>You want to deploy with a different Rack handler (Passenger, Unicorn,
Heroku, ...).</p>
<p>You want to use more than one subclass of <tt>Sinatra::Base</tt>.</p>
<p>You want to use Sinatra only for middleware, but not as endpoint.</p>

<p><b>There is no need to switch to a <tt></tt> only because you
switched to modular style, and you don't have to use modular style for
running with a <tt></tt>.</b></p>

<a name='Using%20Sinatra%20as%20Middleware'></a>
<h3>Using Sinatra as Middleware</h3>

<p>Not only is Sinatra able to use other Rack middleware, any Sinatra
application can in turn be added in front of any Rack endpoint as
middleware itself. This endpoint could be another Sinatra application, or
any other Rack-based application (Rails/Ramaze/Camping/...):</p>

<pre>require 'sinatra/base'

class LoginScreen &lt; Sinatra::Base
  enable :sessions

  get('/login') { haml :login }

  post('/login') do
    if params[:name] == 'admin' &amp;&amp; params[:password] == 'admin'
      session['user_name'] = params[:name]
      redirect '/login'

class MyApp &lt; Sinatra::Base
  # middleware will run before filters
  use LoginScreen

  before do
    unless session['user_name']
      halt &quot;Access denied, please &lt;a href='/login'&gt;login&lt;/a&gt;.&quot;

  get('/') { &quot;Hello #{session['user_name']}.&quot; }

<a name='Dynamic%20Application%20Creation'></a>
<h3>Dynamic Application Creation</h3>

<p>Sometimes you want to create new applications at runtime without having to
assign them to a constant, you can do this with <tt></tt>:</p>

<pre>require 'sinatra/base'
my_app = { get('/') { &quot;hi&quot; } }!</pre>

<p>It takes the application to inherit from as optional argument:</p>

require 'sinatra/base'

controller = do
  enable :logging
  helpers MyHelpers

map('/a') do
  run { get('/') { 'a' } }

map('/b') do
  run { get('/') { 'b' } }

<p>This is especially useful for testing Sinatra extensions or using Sinatra
in your own library.</p>

<p>This also makes using Sinatra as middleware extremely easy:</p>

<pre>require 'sinatra/base'

use Sinatra do
  get('/') { ... }

run RailsProject::Application</pre>

<a name='Scopes%20and%20Binding'></a>
<h2>Scopes and Binding</h2>

<p>The scope you are currently in determines what methods and variables are

<a name='Application/Class%20Scope'></a>
<h3>Application/Class Scope</h3>

<p>Every Sinatra application corresponds to a subclass of
<tt>Sinatra::Base</tt>. If you are using the top-level DSL (<tt>require
'sinatra'</tt>), then this class is <tt>Sinatra::Application</tt>,
otherwise it is the subclass you created explicitly. At class level you
have methods like <tt>get</tt> or <tt>before</tt>, but you cannot access
the <tt>request</tt> object or the <tt>session</tt>, as there only is a
single application class for all requests.</p>

<p>Options created via <tt>set</tt> are methods at class level:</p>

<pre>class MyApp &lt; Sinatra::Base
  # Hey, I'm in the application scope!
  set :foo, 42
  foo # =&gt; 42

  get '/foo' do
    # Hey, I'm no longer in the application scope!

<p>You have the application scope binding inside:</p>
<p>Your application class body</p>
<p>Methods defined by extensions</p>
<p>The block passed to <tt>helpers</tt></p>
<p>Procs/blocks used as value for <tt>set</tt></p>
<p>The block passed to <tt></tt></p>

<p>You can reach the scope object (the class) like this:</p>
<p>Via the object passed to configure blocks (<tt>configure { |c| ... }</tt>)</p>
<p><tt>settings</tt> from within request scope</p>

<a name='Request/Instance%20Scope'></a>
<h3>Request/Instance Scope</h3>

<p>For every incoming request, a new instance of your application class is
created and all handler blocks run in that scope. From within this scope
you can access the <tt>request</tt> and <tt>session</tt> object or call
rendering methods like <tt>erb</tt> or <tt>haml</tt>. You can access the
application scope from within the request scope via the <tt>settings</tt>

<pre>class MyApp &lt; Sinatra::Base
  # Hey, I'm in the application scope!
  get '/define_route/:name' do
    # Request scope for '/define_route/:name'
    @value = 42

    settings.get(&quot;/#{params[:name]}&quot;) do
      # Request scope for &quot;/#{params[:name]}&quot;
      @value # =&gt; nil (not the same request)

    &quot;Route defined!&quot;

<p>You have the request scope binding inside:</p>
<p>get/head/post/put/delete/options blocks</p>
<p>before/after filters</p>
<p>helper methods</p>

<a name='Delegation%20Scope'></a>
<h3>Delegation Scope</h3>

<p>The delegation scope just forwards methods to the class scope. However, it
does not behave 100% like the class scope, as you do not have the class
binding. Only methods explicitly marked for delegation are available and
you do not share variables/state with the class scope (read: you have a
different <tt>self</tt>). You can explicitly add method delegations by
calling <tt>Sinatra::Delegator.delegate :method_name</tt>.</p>

<p>You have the delegate scope binding inside:</p>
<p>The top level binding, if you did <tt>require &quot;sinatra&quot;</tt></p>
<p>An object extended with the <tt>Sinatra::Delegator</tt> mixin</p>

<p>Have a look at the code for yourself: here's the <a
mixin</a> being <a
into the main namespace</a>.</p>

<a name='Command%20Line'></a>
<h2>Command Line</h2>

<p>Sinatra applications can be run directly:</p>

<pre>ruby myapp.rb [-h] [-x] [-e ENVIRONMENT] [-p PORT] [-o HOST] [-s HANDLER]</pre>

<p>Options are:</p>

<pre>-h # help
-p # set the port (default is 4567)
-o # set the host (default is
-e # set the environment (default is development)
-s # specify rack server/handler (default is thin)
-x # turn on the mutex lock (default is off)</pre>

<a name='Requirement'></a>

<p>The following Ruby versions are officially supported:</p>
<dl class="rdoc-list"><dt> Ruby 1.8.7 </dt>
<p>1.8.7 is fully supported, however, if nothing is keeping you from it, we
recommend upgrading to 1.9.2 or switching to JRuby or Rubinius. Support for
1.8.7 will not be dropped before Sinatra 2.0 and Ruby 2.0 except maybe for
the unlikely event of 1.8.8 being released. Even then, we might continue
supporting it. <b>Ruby 1.8.6 is no longer supported.</b> If you want to run
with 1.8.6, downgrade to Sinatra 1.2, which will receive bug fixes until
Sinatra 1.4.0 is released.</p>
</dd><dt> Ruby 1.9.2 </dt>
<p>1.9.2 is fully supported and recommended. Do not use 1.9.2p0, it is known
to cause segmentation faults when running Sinatra. Support will continue at
least until the release of Ruby 1.9.4/2.0 and support for the latest 1.9
release will continue as long as it is still supported by the Ruby core
</dd><dt> Ruby 1.9.3 </dt>
<p>1.9.3 is fully supported and recommended. Please note that switching to
1.9.3 from an earlier version will invalidate all sessions.</p>
</dd><dt> Rubinius </dt>
<p>Rubinius is officially supported (Rubinius &gt;= 1.2.4), everything,
including all template languages, works. The upcoming 2.0 release is
supported as well, including 1.9 mode.</p>
</dd><dt> JRuby </dt>
<p>JRuby is officially supported (JRuby &gt;= 1.6.7). No issues with third
party template libraries are known, however, if you choose to use JRuby,
please look into JRuby rack handlers, as the Thin web server is not fully
supported on JRuby. JRuby's support for C extensions is still experimental,
which only affects RDiscount, Redcarpet, RedCloth and Yajl templates as
well as Thin and Mongrel at the moment.</p>

<p>We also keep an eye on upcoming Ruby versions.</p>

<p>The following Ruby implementations are not officially supported but still
are known to run Sinatra:</p>
<p>Older versions of JRuby and Rubinius</p>
<p>Ruby Enterprise Edition</p>
<p>MacRuby, Maglev, IronRuby</p>
<p>Ruby 1.9.0 and 1.9.1 (but we do recommend against using those)</p>

<p>Not being officially supported means if things only break there and not on
a supported platform, we assume it's not our issue but theirs.</p>

<p>We also run our CI against ruby-head (the upcoming 2.0.0) and the 1.9.4
branch, but we can't guarantee anything, since it is constantly moving.
Expect both 1.9.4p0 and 2.0.0p0 to be supported.</p>

<p>Sinatra should work on any operating system supported by the chosen Ruby

<p>You will not be able to run Sinatra on Cardinal, SmallRuby, BlueRuby or any
Ruby version prior to 1.8.7 as of the time being.</p>

<a name='The%20Bleeding%20Edge'></a>
<h2>The Bleeding Edge</h2>

<p>If you would like to use Sinatra's latest bleeding code, feel free to run
your application against the master branch, it should be rather stable.</p>

<p>We also push out prerelease gems from time to time, so you can do a</p>

<pre>gem install sinatra --pre</pre>

<p>To get some of the latest features.</p>

<a name='With%20Bundler'></a>
<h3>With Bundler</h3>

<p>If you want to run your application with the latest Sinatra, using <a
href="">Bundler</a> is the recommended way.</p>

<p>First, install bundler, if you haven't:</p>

<pre>gem install bundler</pre>

<p>Then, in your project directory, create a <tt>Gemfile</tt>:</p>

<pre>source :rubygems
gem 'sinatra', :git =&gt; &quot;git://;

# other dependencies
gem 'haml'                    # for instance, if you use haml
gem 'activerecord', '~&gt; 3.0'  # maybe you also need ActiveRecord 3.x</pre>

<p>Note that you will have to list all your applications dependencies in
there. Sinatra's direct dependencies (Rack and Tilt) will, however, be
automatically fetched and added by Bundler.</p>

<p>Now you can run your app like this:</p>

<pre>bundle exec ruby myapp.rb</pre>

<a name='Roll%20Your%20Own'></a>
<h3>Roll Your Own</h3>

<p>Create a local clone and run your app with the <tt>sinatra/lib</tt>
directory on the <tt>$LOAD_PATH</tt>:</p>

<pre>cd myapp
git clone git://
ruby -Isinatra/lib myapp.rb</pre>

<p>To update the Sinatra sources in the future:</p>

<pre>cd myapp/sinatra
git pull</pre>

<a name='Install%20Globally'></a>
<h3>Install Globally</h3>

<p>You can build the gem on your own:</p>

<pre>git clone git://
cd sinatra
rake sinatra.gemspec
rake install</pre>

<p>If you install gems as root, the last step should be</p>

<pre>sudo rake install</pre>

<a name='Versioning'></a>

<p>Sinatra follows <a href="">Semantic Versioning</a>, both
SemVer and SemVerTag.</p>

<a name='Further%20Reading'></a>
<h2>Further Reading</h2>
<p><a href="">Project Website</a> - Additional
documentation, news, and links to other resources.</p>
<p><a href="">Contributing</a> - Find a
bug? Need help? Have a patch?</p>
<p><a href="">Issue tracker</a></p>
<p><a href="">Twitter</a></p>
<p><a href="">Mailing List</a></p>
<p><a href="irc://">IRC: #sinatra</a> on <a
<p><a href="">Sinatra Book</a> Cookbook Tutorial</p>
<p><a href="">Sinatra Recipes</a> Community
contributed recipes</p>
<p>API documentation for the <a href="">latest
release</a> or the <a
href="">current HEAD</a> on <a
<p><a href="">CI server</a></p>
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