Question

Is there a way to strip HTML whitespaces in ERB templates, using Sinatra?

The Slim engine does it out-of-the-box, but I don’t know how can ERB do the same.

Answer 1

Sinatra lets you create your own middleware, a possible solution (that works for me) is to create a custom class (middleware in Sinatra’s terms) and use it. The custom class uses a regexp to remove all whitespaces, respecting the content:

class ObfuscateHTML
  def initialize(app, options = {})
    @app = app
  end

  def call(env)
    status, headers, response = @app.call(env)

    if headers["Content-Type"] =~ /\bhtml\b/
      response[0] = response[0].gsub(/\s*(<[^>]+>)\s*/, '\1')
      headers["Content-Length"] = response[0].size.to_s
    end

    [status, headers, response]
  end
end

use ObfuscateHTML