terface between the mruby program and the H2O server is based on <a href="http://www.rubydoc.info/github/rack/rack/master/file/SPEC">Rack interface specification</a>.
Below is a simple configuration that returns <i>hello world</i>.
</p>

<div class="example">
<div class="caption">Example. Hello-world in mruby</div>
<pre><code>paths:
  &quot;/&quot;:
    mruby.handler: |
      Proc.new do |env|
        [200, {&#39;content-type&#39; =&gt; &#39;text/plain&#39;}, [&quot;Hello world\n&quot;]]
      end
</code></