---
title: Webgen::ContentProcessor::Erb
---
## Description

This processer uses ERB (embedded Ruby) to process content. For detailed information about ERB have
a look at its documentation by executing `ri ERB` or the [ruby documentation
site](http://www.ruby-doc.org/)! The short name of the processor is `erb`!

You can use the following special objects in your ERB code:

* `context`: This object provides the whole rendering context, the following objects are just for
  backwards compatibility.

* `ref_node` (or `context.ref_node`): The reference node which is the source of the ERB code that is
  executed. Should be used, for example, for resolving paths.

* `node` (or `context.content_node`): The node that gets currently rendered. Should be used for
  retrieving meta information.

* `dest_node` (or `context.dest_node`): The node in which the result gets inserted. Should be used
  for calculating relative paths.

Here is a small usage example. The following put in a page file

    Counting 5 items dynamically:
    <%% for i in 1..5 %>
      * item <%%= i %>
    <%% end %>

    Outputting all meta information:
    <%% node.meta_info.each do |k,v| %>
      * <%%= k %> = <%%= v %>
    <%% end %>

... will give the result:

    Counting 5 items dynamically:
    <% for i in 1..5 %>
      * item <%= i %>
    <% end %>

    Outputting all meta information:
    <% node.meta_info.each do |k,v| %>
      * <%= k %> = <%= v %>
    <% end %>

The second line shows the first form of the ERB tags which executes Ruby code but does not output
anything: it just starts a `for` loop. On the third line the second form of ERB tags is used to
output the result of the Ruby code (note the equation sign!). And the fourth line completes the
`for` loop by adding the needed `end` keyword.

> You may need to ensure that the ERB start and end tags are not processed by the content
> processor. For example, when using the RedCloth content processor, you may need to surround the
> ERB code with `<textile>` tags!
{.exclamation}