Erubi¶ ↑

Erubi is a ERB template engine for ruby. It is a simplified fork of Erubis, using the same basic algorithm, with the following differences:

Handles postfix conditionals when using escaping (e.g. <%= foo if bar %>)
Supports frozen_string_literal: true in templates via :freeze option
Works with ruby’s --enable-frozen-string-literal option
Automatically freezes strings for template text when ruby optimizes it (on ruby 2.1+)
Escapes ' (apostrophe) when escaping for better XSS protection
Has 6x faster escaping on ruby 2.3+ by using cgi/escape
Has 86% smaller memory footprint
Does no monkey patching (Erubis adds a method to Kernel)
Uses an immutable design (all options passed to the constructor, which returns a frozen object)
Has simpler internals (1 file, <150 lines of code)
Is not dead (Erubis hasn’t been updated since 2011)

It is not designed with Erubis API compatibility in mind, though most Erubis ERB syntax works, with the following exceptions:

No support for <%=== for debug output

Installation¶ ↑

gem install erubi

Source Code¶ ↑

Source code is available on GitHub at github.com/jeremyevans/erubi

Usage¶ ↑

Erubi only has built in support for retrieving the generated source for a file:

require 'erubi'
eval(Erubi::Engine.new(File.read('filename.erb')).src)

Most users will probably use Erubi via Rails or Tilt. Erubi is the default erb template handler in Tilt 2.0.6+ and Rails 5.1+.

Capturing¶ ↑

Erubi does not support capturing block output into the template by default. However, it comes with an erubi/capture_end file that supports capturing via <%|= and <%|== tags which are closed with a <%| tag:

<%|= form do %>
  <input>
<%| end %>

This offers similar functionality to that offered by Rails’ <%= tags, but without the corner cases with that approach (which are due to attempting to parse ruby code via a regexp). Similar to the <%= and <%== tags, <%|= captures by default and <%|== captures and escapes by default, but this can be reversed via the :escape_capture or :escape options.

To use the capture_end support with tilt:

require 'tilt'
require 'erubi/capture_end'
Tilt.new("filename.erb", :engine_class=>Erubi::CaptureEndEngine).render

When using the capture_end support, any methods (such as form in the example above) should return the (potentially modified) buffer. Since the buffer variable is a local variable and not an instance variable by default, you’ll probably want to set the :bufvar variable when using the capture_end support to an instance variable, and have any methods used access that instance variable. Example:

def form
  @_buf << "<form>"
  yield
  @_buf << "</form>"
  @_buf
end

puts eval(Erubi::CaptureEndEngine.new(<<-END, :bufvar=>:@_buf).src)
before
<%|= form do %>
inside
<%| end %>
after
END

# Output:
# before
# <form>
# inside
# </form>
# after

Alternatively, passing the option :yield_returns_buffer => true will return the buffer captured by the block instead of the last expression in the block.

Reporting Bugs¶ ↑

The bug tracker is located at github.com/jeremyevans/erubi/issues

License¶ ↑

MIT

Authors¶ ↑

Jeremy Evans <code@jeremyevans.net> kuwata-lab.com

casperisfine/erubi