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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html><body>
<p><a href="https://badge.fury.io/rb/sinatra"><img src="https://badge.fury.io/rb/sinatra.svg" alt="Gem Version"></a>
<a href="https://github.com/sinatra/sinatra/actions/workflows/test.yml"><img src="https://github.com/sinatra/sinatra/actions/workflows/test.yml/badge.svg" alt="Testing"></a></p>
<p>Sinatra is a <a href="https://en.wikipedia.org/wiki/Domain-specific_language">DSL</a> for
quickly creating web applications in Ruby with minimal effort:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="c1"># myapp.rb</span>
<span class="nb">require</span> <span class="s1">'sinatra'</span>
<span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="s1">'Hello world!'</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Install the gem:</p>
<div class="language-shell highlighter-rouge"><div class="highlight"><pre class="highlight"><code>gem <span class="nb">install </span>sinatra
gem <span class="nb">install </span>puma <span class="c"># or any other server</span>
</code></pre></div></div>
<p>And run with:</p>
<div class="language-shell highlighter-rouge"><div class="highlight"><pre class="highlight"><code>ruby myapp.rb
</code></pre></div></div>
<p>View at: <a href="http://localhost:4567">http://localhost:4567</a></p>
<p>The code you changed will not take effect until you restart the server.
Please restart the server every time you change or use a code reloader
like <a href="https://github.com/alexch/rerun">rerun</a> or
<a href="https://github.com/jeremyevans/rack-unreloader">rack-unreloader</a>.</p>
<p>It is recommended to also run <code>gem install puma</code>, which Sinatra will
pick up if available.</p>
<h2 id="routes">Routes</h2>
<p>In Sinatra, a route is an HTTP method paired with a URL-matching pattern.
Each route is associated with a block:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="o">..</span> <span class="n">show</span> <span class="n">something</span> <span class="o">..</span>
<span class="k">end</span>
<span class="n">post</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="o">..</span> <span class="n">create</span> <span class="n">something</span> <span class="o">..</span>
<span class="k">end</span>
<span class="n">put</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="o">..</span> <span class="n">replace</span> <span class="n">something</span> <span class="o">..</span>
<span class="k">end</span>
<span class="n">patch</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="o">..</span> <span class="n">modify</span> <span class="n">something</span> <span class="o">..</span>
<span class="k">end</span>
<span class="n">delete</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="o">..</span> <span class="n">annihilate</span> <span class="n">something</span> <span class="o">..</span>
<span class="k">end</span>
<span class="n">options</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="o">..</span> <span class="n">appease</span> <span class="n">something</span> <span class="o">..</span>
<span class="k">end</span>
<span class="n">link</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="o">..</span> <span class="n">affiliate</span> <span class="n">something</span> <span class="o">..</span>
<span class="k">end</span>
<span class="n">unlink</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="o">..</span> <span class="n">separate</span> <span class="n">something</span> <span class="o">..</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Routes are matched in the order they are defined. The first route that
matches the request is invoked.</p>
<p>Routes with trailing slashes are different from the ones without:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/foo'</span> <span class="k">do</span>
<span class="c1"># Does not match "GET /foo/"</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Route patterns may include named parameters, accessible via the
<code>params</code> hash:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/hello/:name'</span> <span class="k">do</span>
<span class="c1"># matches "GET /hello/foo" and "GET /hello/bar"</span>
<span class="c1"># params['name'] is 'foo' or 'bar'</span>
<span class="s2">"Hello </span><span class="si">#{</span><span class="n">params</span><span class="p">[</span><span class="s1">'name'</span><span class="p">]</span><span class="si">}</span><span class="s2">!"</span>
<span class="k">end</span>
</code></pre></div></div>
<p>You can also access named parameters via block parameters:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/hello/:name'</span> <span class="k">do</span> <span class="o">|</span><span class="n">n</span><span class="o">|</span>
<span class="c1"># matches "GET /hello/foo" and "GET /hello/bar"</span>
<span class="c1"># params['name'] is 'foo' or 'bar'</span>
<span class="c1"># n stores params['name']</span>
<span class="s2">"Hello </span><span class="si">#{</span><span class="n">n</span><span class="si">}</span><span class="s2">!"</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Route patterns may also include splat (or wildcard) parameters, accessible
via the <code>params['splat']</code> array:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/say/*/to/*'</span> <span class="k">do</span>
<span class="c1"># matches /say/hello/to/world</span>
<span class="n">params</span><span class="p">[</span><span class="s1">'splat'</span><span class="p">]</span> <span class="c1"># => ["hello", "world"]</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s1">'/download/*.*'</span> <span class="k">do</span>
<span class="c1"># matches /download/path/to/file.xml</span>
<span class="n">params</span><span class="p">[</span><span class="s1">'splat'</span><span class="p">]</span> <span class="c1"># => ["path/to/file", "xml"]</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Or with block parameters:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/download/*.*'</span> <span class="k">do</span> <span class="o">|</span><span class="n">path</span><span class="p">,</span> <span class="n">ext</span><span class="o">|</span>
<span class="p">[</span><span class="n">path</span><span class="p">,</span> <span class="n">ext</span><span class="p">]</span> <span class="c1"># => ["path/to/file", "xml"]</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Route matching with Regular Expressions:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="sr">/\/hello\/([\w]+)/</span> <span class="k">do</span>
<span class="s2">"Hello, </span><span class="si">#{</span><span class="n">params</span><span class="p">[</span><span class="s1">'captures'</span><span class="p">].</span><span class="nf">first</span><span class="si">}</span><span class="s2">!"</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Or with a block parameter:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="sr">%r{/hello/([</span><span class="se">\w</span><span class="sr">]+)}</span> <span class="k">do</span> <span class="o">|</span><span class="n">c</span><span class="o">|</span>
<span class="c1"># Matches "GET /meta/hello/world", "GET /hello/world/1234" etc.</span>
<span class="s2">"Hello, </span><span class="si">#{</span><span class="n">c</span><span class="si">}</span><span class="s2">!"</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Route patterns may have optional parameters:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/posts/:format?'</span> <span class="k">do</span>
<span class="c1"># matches "GET /posts/" and any extension "GET /posts/json", "GET /posts/xml" etc</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Routes may also utilize query parameters:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/posts'</span> <span class="k">do</span>
<span class="c1"># matches "GET /posts?title=foo&author=bar"</span>
<span class="n">title</span> <span class="o">=</span> <span class="n">params</span><span class="p">[</span><span class="s1">'title'</span><span class="p">]</span>
<span class="n">author</span> <span class="o">=</span> <span class="n">params</span><span class="p">[</span><span class="s1">'author'</span><span class="p">]</span>
<span class="c1"># uses title and author variables; query is optional to the /posts route</span>
<span class="k">end</span>
</code></pre></div></div>
<p>By the way, unless you disable the path traversal attack protection (see
<a href="#configuring-attack-protection">below</a>), the request path might be modified before
matching against your routes.</p>
<p>You may customize the <a href="https://github.com/sinatra/mustermann#readme">Mustermann</a>
options used for a given route by passing in a <code>:mustermann_opts</code> hash:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'\A/posts\z'</span><span class="p">,</span> <span class="ss">:mustermann_opts</span> <span class="o">=></span> <span class="p">{</span> <span class="ss">:type</span> <span class="o">=></span> <span class="ss">:regexp</span><span class="p">,</span> <span class="ss">:check_anchors</span> <span class="o">=></span> <span class="kp">false</span> <span class="p">}</span> <span class="k">do</span>
<span class="c1"># matches /posts exactly, with explicit anchoring</span>
<span class="s2">"If you match an anchored pattern clap your hands!"</span>
<span class="k">end</span>
</code></pre></div></div>
<p>It looks like a <a href="#conditions">condition</a>, but it isn’t one! These options will
be merged into the global <code>:mustermann_opts</code> hash described
<a href="#available-settings">below</a>.</p>
<h2 id="conditions">Conditions</h2>
<p>Routes may include a variety of matching conditions, such as the user agent:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/foo'</span><span class="p">,</span> <span class="ss">:agent</span> <span class="o">=></span> <span class="sr">/Songbird (\d\.\d)[\d\/]*?/</span> <span class="k">do</span>
<span class="s2">"You're using Songbird version </span><span class="si">#{</span><span class="n">params</span><span class="p">[</span><span class="s1">'agent'</span><span class="p">][</span><span class="mi">0</span><span class="p">]</span><span class="si">}</span><span class="s2">"</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s1">'/foo'</span> <span class="k">do</span>
<span class="c1"># Matches non-songbird browsers</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Other available conditions are <code>host_name</code> and <code>provides</code>:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/'</span><span class="p">,</span> <span class="ss">:host_name</span> <span class="o">=></span> <span class="sr">/^admin\./</span> <span class="k">do</span>
<span class="s2">"Admin Area, Access denied!"</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s1">'/'</span><span class="p">,</span> <span class="ss">:provides</span> <span class="o">=></span> <span class="s1">'html'</span> <span class="k">do</span>
<span class="n">haml</span> <span class="ss">:index</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s1">'/'</span><span class="p">,</span> <span class="ss">:provides</span> <span class="o">=></span> <span class="p">[</span><span class="s1">'rss'</span><span class="p">,</span> <span class="s1">'atom'</span><span class="p">,</span> <span class="s1">'xml'</span><span class="p">]</span> <span class="k">do</span>
<span class="n">builder</span> <span class="ss">:feed</span>
<span class="k">end</span>
</code></pre></div></div>
<p><code>provides</code> searches the request’s Accept header.</p>
<p>You can easily define your own conditions:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">set</span><span class="p">(</span><span class="ss">:probability</span><span class="p">)</span> <span class="p">{</span> <span class="o">|</span><span class="n">value</span><span class="o">|</span> <span class="n">condition</span> <span class="p">{</span> <span class="nb">rand</span> <span class="o"><=</span> <span class="n">value</span> <span class="p">}</span> <span class="p">}</span>
<span class="n">get</span> <span class="s1">'/win_a_car'</span><span class="p">,</span> <span class="ss">:probability</span> <span class="o">=></span> <span class="mf">0.1</span> <span class="k">do</span>
<span class="s2">"You won!"</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s1">'/win_a_car'</span> <span class="k">do</span>
<span class="s2">"Sorry, you lost."</span>
<span class="k">end</span>
</code></pre></div></div>
<p>For a condition that takes multiple values use a splat:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">set</span><span class="p">(</span><span class="ss">:auth</span><span class="p">)</span> <span class="k">do</span> <span class="o">|*</span><span class="n">roles</span><span class="o">|</span> <span class="c1"># <- notice the splat here</span>
<span class="n">condition</span> <span class="k">do</span>
<span class="k">unless</span> <span class="n">logged_in?</span> <span class="o">&&</span> <span class="n">roles</span><span class="p">.</span><span class="nf">any?</span> <span class="p">{</span><span class="o">|</span><span class="n">role</span><span class="o">|</span> <span class="n">current_user</span><span class="p">.</span><span class="nf">in_role?</span> <span class="n">role</span> <span class="p">}</span>
<span class="n">redirect</span> <span class="s2">"/login/"</span><span class="p">,</span> <span class="mi">303</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s2">"/my/account/"</span><span class="p">,</span> <span class="ss">:auth</span> <span class="o">=></span> <span class="p">[</span><span class="ss">:user</span><span class="p">,</span> <span class="ss">:admin</span><span class="p">]</span> <span class="k">do</span>
<span class="s2">"Your Account Details"</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s2">"/only/admin/"</span><span class="p">,</span> <span class="ss">:auth</span> <span class="o">=></span> <span class="ss">:admin</span> <span class="k">do</span>
<span class="s2">"Only admins are allowed here!"</span>
<span class="k">end</span>
</code></pre></div></div>
<h2 id="return-values">Return Values</h2>
<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 an object that would either be a valid Rack response, Rack
body object or HTTP status code:</p>
<ul>
<li>An Array with three elements: <code>[status (Integer), headers (Hash), response
body (responds to #each)]</code>
</li>
<li>An Array with two elements: <code>[status (Integer), response body (responds to
#each)]</code>
</li>
<li>An object that responds to <code>#each</code> and passes nothing but strings to
the given block</li>
<li>A Integer representing the status code</li>
</ul>
<p>That way we can, for instance, easily implement a streaming example:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="k">class</span> <span class="nc">Stream</span>
<span class="k">def</span> <span class="nf">each</span>
<span class="mi">100</span><span class="p">.</span><span class="nf">times</span> <span class="p">{</span> <span class="o">|</span><span class="n">i</span><span class="o">|</span> <span class="k">yield</span> <span class="s2">"</span><span class="si">#{</span><span class="n">i</span><span class="si">}</span><span class="se">\n</span><span class="s2">"</span> <span class="p">}</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="n">get</span><span class="p">(</span><span class="s1">'/'</span><span class="p">)</span> <span class="p">{</span> <span class="no">Stream</span><span class="p">.</span><span class="nf">new</span> <span class="p">}</span>
</code></pre></div></div>
<p>You can also use the <code>stream</code> helper method (<a href="#streaming-responses">described below</a>) to reduce
boilerplate and embed the streaming logic in the route.</p>
<h2 id="custom-route-matchers">Custom Route Matchers</h2>
<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>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="k">class</span> <span class="nc">AllButPattern</span>
<span class="k">def</span> <span class="nf">initialize</span><span class="p">(</span><span class="n">except</span><span class="p">)</span>
<span class="vi">@except</span> <span class="o">=</span> <span class="n">except</span>
<span class="k">end</span>
<span class="k">def</span> <span class="nf">to_pattern</span><span class="p">(</span><span class="n">options</span><span class="p">)</span>
<span class="k">return</span> <span class="nb">self</span>
<span class="k">end</span>
<span class="k">def</span> <span class="nf">params</span><span class="p">(</span><span class="n">route</span><span class="p">)</span>
<span class="k">return</span> <span class="p">{}</span> <span class="k">unless</span> <span class="vi">@except</span> <span class="o">===</span> <span class="n">route</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="k">def</span> <span class="nf">all_but</span><span class="p">(</span><span class="n">pattern</span><span class="p">)</span>
<span class="no">AllButPattern</span><span class="p">.</span><span class="nf">new</span><span class="p">(</span><span class="n">pattern</span><span class="p">)</span>
<span class="k">end</span>
<span class="n">get</span> <span class="n">all_but</span><span class="p">(</span><span class="s2">"/index"</span><span class="p">)</span> <span class="k">do</span>
<span class="c1"># ...</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Note that the above example might be over-engineered, as it can also be
expressed as:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="sr">/.*/</span> <span class="k">do</span>
<span class="n">pass</span> <span class="k">if</span> <span class="n">request</span><span class="p">.</span><span class="nf">path_info</span> <span class="o">==</span> <span class="s2">"/index"</span>
<span class="c1"># ...</span>
<span class="k">end</span>
</code></pre></div></div>
<h2 id="static-files">Static Files</h2>
<p>Static files are served from the <code>./public</code> directory. You can specify
a different location by setting the <code>:public_folder</code> option:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">set</span> <span class="ss">:public_folder</span><span class="p">,</span> <span class="n">__dir__</span> <span class="o">+</span> <span class="s1">'/static'</span>
</code></pre></div></div>
<p>Note that the public directory name is not included in the URL. A file
<code>./public/css/style.css</code> is made available as
<code>http://example.com/css/style.css</code>.</p>
<p>Use the <code>:static_cache_control</code> setting (see <a href="#cache-control">below</a>) to add
<code>Cache-Control</code> header info.</p>
<h2 id="views--templates">Views / Templates</h2>
<p>Each template language is exposed via its own rendering method. These
methods simply return a string:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">erb</span> <span class="ss">:index</span>
<span class="k">end</span>
</code></pre></div></div>
<p>This renders <code>views/index.erb</code>.</p>
<p>Instead of a template name, you can also just pass in the template content
directly:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">code</span> <span class="o">=</span> <span class="s2">"<%= Time.now %>"</span>
<span class="n">erb</span> <span class="n">code</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Templates take a second argument, the options hash:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">erb</span> <span class="ss">:index</span><span class="p">,</span> <span class="ss">:layout</span> <span class="o">=></span> <span class="ss">:post</span>
<span class="k">end</span>
</code></pre></div></div>
<p>This will render <code>views/index.erb</code> embedded in the
<code>views/post.erb</code> (default is <code>views/layout.erb</code>, if it exists).</p>
<p>Any options not understood by Sinatra will be passed on to the template
engine:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">haml</span> <span class="ss">:index</span><span class="p">,</span> <span class="ss">:format</span> <span class="o">=></span> <span class="ss">:html5</span>
<span class="k">end</span>
</code></pre></div></div>
<p>You can also set options per template language in general:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">set</span> <span class="ss">:haml</span><span class="p">,</span> <span class="ss">:format</span> <span class="o">=></span> <span class="ss">:html5</span>
<span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">haml</span> <span class="ss">:index</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Options passed to the render method override options set via <code>set</code>.</p>
<p>Available Options:</p>
<dl>
<dt>locals</dt>
<dd>
List of locals passed to the document. Handy with partials.
Example: <tt>erb "<%= foo %>", :locals => {:foo => "bar"}</tt>
</dd>
<dt>default_encoding</dt>
<dd>
String encoding to use if uncertain. Defaults to
<tt>settings.default_encoding</tt>.
</dd>
<dt>views</dt>
<dd>
Views folder to load templates from. Defaults to <tt>settings.views</tt>.
</dd>
<dt>layout</dt>
<dd>
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 => !request.xhr?</tt>
</dd>
<dt>content_type</dt>
<dd>
Content-Type the template produces. Default depends on template language.
</dd>
<dt>scope</dt>
<dd>
Scope to render template under. Defaults to the application
instance. If you change this, instance variables and helper methods
will not be available.
</dd>
<dt>layout_engine</dt>
<dd>
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
=> :erb</tt>
</dd>
<dt>layout_options</dt>
<dd>
Special options only used for rendering the layout. Example:
<tt>set :rdoc, :layout_options => { :views => 'views/layouts' }</tt>
</dd>
</dl>
<p>Templates are assumed to be located directly under the <code>./views</code>
directory. To use a different views directory:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">set</span> <span class="ss">:views</span><span class="p">,</span> <span class="n">settings</span><span class="p">.</span><span class="nf">root</span> <span class="o">+</span> <span class="s1">'/templates'</span>
</code></pre></div></div>
<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: <code>:'subdir/template'</code> or <code>'subdir/template'.to_sym</code>). You must use a
symbol because otherwise rendering methods will render any strings
passed to them directly.</p>
<h3 id="literal-templates">Literal Templates</h3>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">haml</span> <span class="s1">'%div.title Hello World'</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Renders the template string. You can optionally specify <code>:path</code> and
<code>:line</code> for a clearer backtrace if there is a filesystem path or line
associated with that string:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">haml</span> <span class="s1">'%div.title Hello World'</span><span class="p">,</span> <span class="ss">:path</span> <span class="o">=></span> <span class="s1">'examples/file.haml'</span><span class="p">,</span> <span class="ss">:line</span> <span class="o">=></span> <span class="mi">3</span>
<span class="k">end</span>
</code></pre></div></div>
<h3 id="available-template-languages">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 first:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nb">require</span> <span class="s1">'rdiscount'</span>
<span class="n">get</span><span class="p">(</span><span class="s1">'/'</span><span class="p">)</span> <span class="p">{</span> <span class="n">markdown</span> <span class="ss">:index</span> <span class="p">}</span>
</code></pre></div></div>
<h4 id="haml-templates">Haml Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td><a href="http://haml.info/" title="haml">haml</a></td>
</tr>
<tr>
<td>File Extension</td>
<td><tt>.haml</tt></td>
</tr>
<tr>
<td>Example</td>
<td><tt>haml :index, :format => :html5</tt></td>
</tr>
</table>
<h4 id="erb-templates">Erb Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td>
<a href="https://github.com/jeremyevans/erubi" title="erubi">erubi</a>
or erb (included in Ruby)
</td>
</tr>
<tr>
<td>File Extensions</td>
<td>
<tt>.erb</tt>, <tt>.rhtml</tt> or <tt>.erubi</tt> (Erubi only)</td>
</tr>
<tr>
<td>Example</td>
<td><tt>erb :index</tt></td>
</tr>
</table>
<h4 id="builder-templates">Builder Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td>
<a href="https://github.com/jimweirich/builder" title="builder">builder</a>
</td>
</tr>
<tr>
<td>File Extension</td>
<td><tt>.builder</tt></td>
</tr>
<tr>
<td>Example</td>
<td><tt>builder { |xml| xml.em "hi" }</tt></td>
</tr>
</table>
<p>It also takes a block for inline templates (see <a href="#inline-templates">example</a>).</p>
<h4 id="nokogiri-templates">Nokogiri Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td><a href="http://www.nokogiri.org/" title="nokogiri">nokogiri</a></td>
</tr>
<tr>
<td>File Extension</td>
<td><tt>.nokogiri</tt></td>
</tr>
<tr>
<td>Example</td>
<td><tt>nokogiri { |xml| xml.em "hi" }</tt></td>
</tr>
</table>
<p>It also takes a block for inline templates (see <a href="#inline-templates">example</a>).</p>
<h4 id="liquid-templates">Liquid Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td><a href="https://shopify.github.io/liquid/" title="liquid">liquid</a></td>
</tr>
<tr>
<td>File Extension</td>
<td><tt>.liquid</tt></td>
</tr>
<tr>
<td>Example</td>
<td><tt>liquid :index, :locals => { :key => 'value' }</tt></td>
</tr>
</table>
<p>Since you cannot call Ruby methods (except for <code>yield</code>) from a Liquid
template, you almost always want to pass locals to it.</p>
<h4 id="markdown-templates">Markdown Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td>
Anyone of:
<a href="https://github.com/davidfstr/rdiscount" title="RDiscount">RDiscount</a>,
<a href="https://github.com/vmg/redcarpet" title="RedCarpet">RedCarpet</a>,
<a href="https://kramdown.gettalong.org/" title="kramdown">kramdown</a>,
<a href="https://github.com/gjtorikian/commonmarker" title="commonmarker">commonmarker</a>
<a href="https://github.com/alphabetum/pandoc-ruby" title="pandoc">pandoc</a>
</td>
</tr>
<tr>
<td>File Extensions</td>
<td>
<tt>.markdown</tt>, <tt>.mkd</tt> and <tt>.md</tt>
</td>
</tr>
<tr>
<td>Example</td>
<td><tt>markdown :index, :layout_engine => :erb</tt></td>
</tr>
</table>
<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
engine:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">erb</span> <span class="ss">:overview</span><span class="p">,</span> <span class="ss">:locals</span> <span class="o">=></span> <span class="p">{</span> <span class="ss">:text</span> <span class="o">=></span> <span class="n">markdown</span><span class="p">(</span><span class="ss">:introduction</span><span class="p">)</span> <span class="p">}</span>
</code></pre></div></div>
<p>Note that you may also call the <code>markdown</code> method from within other
templates:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">%</span><span class="n">h1</span> <span class="no">Hello</span> <span class="no">From</span> <span class="no">Haml</span><span class="o">!</span>
<span class="o">%</span><span class="nb">p</span><span class="o">=</span> <span class="n">markdown</span><span class="p">(</span><span class="ss">:greetings</span><span class="p">)</span>
</code></pre></div></div>
<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 <code>:layout_engine</code> option.</p>
<h4 id="rdoc-templates">RDoc Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td><a href="http://rdoc.sourceforge.net/" title="RDoc">RDoc</a></td>
</tr>
<tr>
<td>File Extension</td>
<td><tt>.rdoc</tt></td>
</tr>
<tr>
<td>Example</td>
<td><tt>rdoc :README, :layout_engine => :erb</tt></td>
</tr>
</table>
<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>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">erb</span> <span class="ss">:overview</span><span class="p">,</span> <span class="ss">:locals</span> <span class="o">=></span> <span class="p">{</span> <span class="ss">:text</span> <span class="o">=></span> <span class="n">rdoc</span><span class="p">(</span><span class="ss">:introduction</span><span class="p">)</span> <span class="p">}</span>
</code></pre></div></div>
<p>Note that you may also call the <code>rdoc</code> method from within other templates:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">%</span><span class="n">h1</span> <span class="no">Hello</span> <span class="no">From</span> <span class="no">Haml</span><span class="o">!</span>
<span class="o">%</span><span class="nb">p</span><span class="o">=</span> <span class="n">rdoc</span><span class="p">(</span><span class="ss">:greetings</span><span class="p">)</span>
</code></pre></div></div>
<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 <code>:layout_engine</code> option.</p>
<h4 id="asciidoc-templates">AsciiDoc Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td><a href="http://asciidoctor.org/" title="Asciidoctor">Asciidoctor</a></td>
</tr>
<tr>
<td>File Extension</td>
<td>
<tt>.asciidoc</tt>, <tt>.adoc</tt> and <tt>.ad</tt>
</td>
</tr>
<tr>
<td>Example</td>
<td><tt>asciidoc :README, :layout_engine => :erb</tt></td>
</tr>
</table>
<p>Since you cannot call Ruby methods directly from an AsciiDoc template, you
almost always want to pass locals to it.</p>
<h4 id="markaby-templates">Markaby Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td><a href="https://markaby.github.io/" title="Markaby">Markaby</a></td>
</tr>
<tr>
<td>File Extension</td>
<td><tt>.mab</tt></td>
</tr>
<tr>
<td>Example</td>
<td><tt>markaby { h1 "Welcome!" }</tt></td>
</tr>
</table>
<p>It also takes a block for inline templates (see <a href="#inline-templates">example</a>).</p>
<h4 id="rabl-templates">RABL Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td><a href="https://github.com/nesquena/rabl" title="Rabl">Rabl</a></td>
</tr>
<tr>
<td>File Extension</td>
<td><tt>.rabl</tt></td>
</tr>
<tr>
<td>Example</td>
<td><tt>rabl :index</tt></td>
</tr>
</table>
<h4 id="slim-templates">Slim Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td><a href="http://slim-lang.com/" title="Slim Lang">Slim Lang</a></td>
</tr>
<tr>
<td>File Extension</td>
<td><tt>.slim</tt></td>
</tr>
<tr>
<td>Example</td>
<td><tt>slim :index</tt></td>
</tr>
</table>
<h4 id="yajl-templates">Yajl Templates</h4>
<table>
<tr>
<td>Dependency</td>
<td><a href="https://github.com/brianmario/yajl-ruby" title="yajl-ruby">yajl-ruby</a></td>
</tr>
<tr>
<td>File Extension</td>
<td><tt>.yajl</tt></td>
</tr>
<tr>
<td>Example</td>
<td>
<tt>
yajl :index,
:locals => { :key => 'qux' },
:callback => 'present',
:variable => 'resource'
</tt>
</td>
</tr>
</table>
<p>The template source is evaluated as a Ruby string, and the
resulting json variable is converted using <code>#to_json</code>:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">json</span> <span class="o">=</span> <span class="p">{</span> <span class="ss">:foo</span> <span class="o">=></span> <span class="s1">'bar'</span> <span class="p">}</span>
<span class="n">json</span><span class="p">[</span><span class="ss">:baz</span><span class="p">]</span> <span class="o">=</span> <span class="n">key</span>
</code></pre></div></div>
<p>The <code>:callback</code> and <code>:variable</code> options can be used to decorate the rendered
object:</p>
<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">var</span> <span class="nx">resource</span> <span class="o">=</span> <span class="p">{</span><span class="dl">"</span><span class="s2">foo</span><span class="dl">"</span><span class="p">:</span><span class="dl">"</span><span class="s2">bar</span><span class="dl">"</span><span class="p">,</span><span class="dl">"</span><span class="s2">baz</span><span class="dl">"</span><span class="p">:</span><span class="dl">"</span><span class="s2">qux</span><span class="dl">"</span><span class="p">};</span>
<span class="nx">present</span><span class="p">(</span><span class="nx">resource</span><span class="p">);</span>
</code></pre></div></div>
<h3 id="accessing-variables-in-templates">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>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/:id'</span> <span class="k">do</span>
<span class="vi">@foo</span> <span class="o">=</span> <span class="no">Foo</span><span class="p">.</span><span class="nf">find</span><span class="p">(</span><span class="n">params</span><span class="p">[</span><span class="s1">'id'</span><span class="p">])</span>
<span class="n">haml</span> <span class="s1">'%h1= @foo.name'</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Or, specify an explicit Hash of local variables:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/:id'</span> <span class="k">do</span>
<span class="n">foo</span> <span class="o">=</span> <span class="no">Foo</span><span class="p">.</span><span class="nf">find</span><span class="p">(</span><span class="n">params</span><span class="p">[</span><span class="s1">'id'</span><span class="p">])</span>
<span class="n">haml</span> <span class="s1">'%h1= bar.name'</span><span class="p">,</span> <span class="ss">:locals</span> <span class="o">=></span> <span class="p">{</span> <span class="ss">:bar</span> <span class="o">=></span> <span class="n">foo</span> <span class="p">}</span>
<span class="k">end</span>
</code></pre></div></div>
<p>This is typically used when rendering templates as partials from within
other templates.</p>
<h3 id="templates-with-yield-and-nested-layouts">Templates with <code>yield</code> and nested layouts</h3>
<p>A layout is usually just a template that calls <code>yield</code>.
Such a template can be used either through the <code>:template</code> option as
described above, or it can be rendered with a block as follows:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">erb</span> <span class="ss">:post</span><span class="p">,</span> <span class="ss">:layout</span> <span class="o">=></span> <span class="kp">false</span> <span class="k">do</span>
<span class="n">erb</span> <span class="ss">:index</span>
<span class="k">end</span>
</code></pre></div></div>
<p>This code is mostly equivalent to <code>erb :index, :layout => :post</code>.</p>
<p>Passing blocks to rendering methods is most useful for creating nested
layouts:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">erb</span> <span class="ss">:main_layout</span><span class="p">,</span> <span class="ss">:layout</span> <span class="o">=></span> <span class="kp">false</span> <span class="k">do</span>
<span class="n">erb</span> <span class="ss">:admin_layout</span> <span class="k">do</span>
<span class="n">erb</span> <span class="ss">:user</span>
<span class="k">end</span>
<span class="k">end</span>
</code></pre></div></div>
<p>This can also be done in fewer lines of code with:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">erb</span> <span class="ss">:admin_layout</span><span class="p">,</span> <span class="ss">:layout</span> <span class="o">=></span> <span class="ss">:main_layout</span> <span class="k">do</span>
<span class="n">erb</span> <span class="ss">:user</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Currently, the following rendering methods accept a block: <code>erb</code>, <code>haml</code>,
<code>liquid</code>, <code>slim </code>. Also, the general <code>render</code> method accepts a block.</p>
<h3 id="inline-templates">Inline Templates</h3>
<p>Templates may be defined at the end of the source file:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nb">require</span> <span class="s1">'sinatra'</span>
<span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">haml</span> <span class="ss">:index</span>
<span class="k">end</span>
<span class="cp">__END__
@@ layout
%html
!= yield
@@ index
%div.title Hello world.
</span></code></pre></div></div>
<p>NOTE: Inline templates defined in the source file that requires Sinatra are
automatically loaded. Call <code>enable :inline_templates</code> explicitly if you
have inline templates in other source files.</p>
<h3 id="named-templates">Named Templates</h3>
<p>Templates may also be defined using the top-level <code>template</code> method:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">template</span> <span class="ss">:layout</span> <span class="k">do</span>
<span class="s2">"%html</span><span class="se">\n</span><span class="s2"> =yield</span><span class="se">\n</span><span class="s2">"</span>
<span class="k">end</span>
<span class="n">template</span> <span class="ss">:index</span> <span class="k">do</span>
<span class="s1">'%div.title Hello World!'</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">haml</span> <span class="ss">:index</span>
<span class="k">end</span>
</code></pre></div></div>
<p>If a template named “layout” exists, it will be used each time a template
is rendered. You can individually disable layouts by passing
<code>:layout => false</code> or disable them by default via
<code>set :haml, :layout => false</code>:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">haml</span> <span class="ss">:index</span><span class="p">,</span> <span class="ss">:layout</span> <span class="o">=></span> <span class="o">!</span><span class="n">request</span><span class="p">.</span><span class="nf">xhr?</span>
<span class="k">end</span>
</code></pre></div></div>
<h3 id="associating-file-extensions">Associating File Extensions</h3>
<p>To associate a file extension with a template engine, use
<code>Tilt.register</code>. For instance, if you like to use the file extension
<code>tt</code> for Haml templates, you can do the following:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="no">Tilt</span><span class="p">.</span><span class="nf">register</span> <span class="no">Tilt</span><span class="p">[</span><span class="ss">:haml</span><span class="p">],</span> <span class="ss">:tt</span>
</code></pre></div></div>
<h3 id="adding-your-own-template-engine">Adding Your Own Template Engine</h3>
<p>First, register your engine with Tilt, then create a rendering method:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="no">Tilt</span><span class="p">.</span><span class="nf">register</span> <span class="no">MyAwesomeTemplateEngine</span><span class="p">,</span> <span class="ss">:myat</span>
<span class="n">helpers</span> <span class="k">do</span>
<span class="k">def</span> <span class="nf">myat</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">)</span> <span class="n">render</span><span class="p">(</span><span class="ss">:myat</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">)</span> <span class="k">end</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s1">'/'</span> <span class="k">do</span>
<span class="n">myat</span> <span class="ss">:index</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Renders <code>./views/index.myat</code>. Learn more about
<a href="https://github.com/rtomayko/tilt#readme">Tilt</a>.</p>
<h3 id="using-custom-logic-for-template-lookup">Using Custom Logic for Template Lookup</h3>
<p>To implement your own template lookup mechanism you can write your
own <code>#find_template</code> method:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">configure</span> <span class="k">do</span>
<span class="n">set</span> <span class="ss">:views</span><span class="p">,</span> <span class="p">[</span> <span class="s1">'./views/a'</span><span class="p">,</span> <span class="s1">'./views/b'</span> <span class="p">]</span>
<span class="k">end</span>
<span class="k">def</span> <span class="nf">find_template</span><span class="p">(</span><span class="n">views</span><span class="p">,</span> <span class="nb">name</span><span class="p">,</span> <span class="n">engine</span><span class="p">,</span> <span class="o">&</span><span class="n">block</span><span class="p">)</span>
<span class="no">Array</span><span class="p">(</span><span class="n">views</span><span class="p">).</span><span class="nf">each</span> <span class="k">do</span> <span class="o">|</span><span class="n">v</span><span class="o">|</span>
<span class="k">super</span><span class="p">(</span><span class="n">v</span><span class="p">,</span> <span class="nb">name</span><span class="p">,</span> <span class="n">engine</span><span class="p">,</span> <span class="o">&</span><span class="n">block</span><span class="p">)</span>
<span class="k">end</span>
<span class="k">end</span>
</code></pre></div></div>
<h2 id="filters">Filters</h2>
<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>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">before</span> <span class="k">do</span>
<span class="vi">@note</span> <span class="o">=</span> <span class="s1">'Hi!'</span>
<span class="n">request</span><span class="p">.</span><span class="nf">path_info</span> <span class="o">=</span> <span class="s1">'/foo/bar/baz'</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s1">'/foo/*'</span> <span class="k">do</span>
<span class="vi">@note</span> <span class="c1">#=> 'Hi!'</span>
<span class="n">params</span><span class="p">[</span><span class="s1">'splat'</span><span class="p">]</span> <span class="c1">#=> 'bar/baz'</span>
<span class="k">end</span>
</code></pre></div></div>
<p>After filters are evaluated after each request within the same context
as the routes will be and can also modify the request and response.
Instance variables set in before filters and routes are accessible by
after filters:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">after</span> <span class="k">do</span>
<span class="nb">puts</span> <span class="n">response</span><span class="p">.</span><span class="nf">status</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Note: Unless you use the <code>body</code> 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>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">before</span> <span class="s1">'/protected/*'</span> <span class="k">do</span>
<span class="n">authenticate!</span>
<span class="k">end</span>
<span class="n">after</span> <span class="s1">'/create/:slug'</span> <span class="k">do</span> <span class="o">|</span><span class="n">slug</span><span class="o">|</span>
<span class="n">session</span><span class="p">[</span><span class="ss">:last_slug</span><span class="p">]</span> <span class="o">=</span> <span class="n">slug</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Like routes, filters also take conditions:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">before</span> <span class="ss">:agent</span> <span class="o">=></span> <span class="sr">/Songbird/</span> <span class="k">do</span>
<span class="c1"># ...</span>
<span class="k">end</span>
<span class="n">after</span> <span class="s1">'/blog/*'</span><span class="p">,</span> <span class="ss">:host_name</span> <span class="o">=></span> <span class="s1">'example.com'</span> <span class="k">do</span>
<span class="c1"># ...</span>
<span class="k">end</span>
</code></pre></div></div>
<h2 id="helpers">Helpers</h2>
<p>Use the top-level <code>helpers</code> method to define helper methods for use in
route handlers and templates:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">helpers</span> <span class="k">do</span>
<span class="k">def</span> <span class="nf">bar</span><span class="p">(</span><span class="nb">name</span><span class="p">)</span>
<span class="s2">"</span><span class="si">#{</span><span class="nb">name</span><span class="si">}</span><span class="s2">bar"</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="n">get</span> <span class="s1">'/:name'</span> <span class="k">do</span>
<span class="n">bar</span><span class="p">(</span><span class="n">params</span><span class="p">[</span><span class="s1">'name'</span><span class="p">])</span>
<span class="k">end</span>
</code></pre></div></div>
<p>Alternatively, helper methods can be separately defined in a module:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="k">module</span> <span class="nn">FooUtils</span>
<span class="k">def</span> <span class="nf">foo</span><span class="p">(</span><span class="nb">name</span><span class="p">)</span> <span class="s2">"</span><span class="si">#{</span><span class="nb">name</span><span class="si">}</span><span class="s2">foo"</span> <span class="k">end</span>
<span class="k">end</span>
<span class="k">module</span> <span class="nn">BarUtils</span>
<span class="k">def</span> <span class="nf">bar</span><span class="p">(</span><span class="nb">name</span><span class="p">)</span> <span class="s2">"</span><span class="si">#{</span><span class="nb">name</span><span class="si">}</span><span class="s2">bar"</span> <span class="k">end</span>
<span class="k">end</span>
<span class="n">helpers</span> <span class="no">FooUtils</span><span class="p">,</span> <span class="no">BarUtils</span>
</code></pre></div></div>
<p>The effect is the same as including the modules in the application class.</p>
<h3 id="using-sessions">Using Sessions</h3>
<p>A session is used to keep state during requests. If activated, you have one
session hash per user session:</p>
<div class="language-ruby highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">enable</span> <span class="ss">:sessions</span>