ActionController::Head
Methods
H
Instance Public methods
head(status, options = {})

Returns a response that has no content (merely headers). The options argument is interpreted to be a hash of header names and values. This allows you to easily return a response that consists only of significant headers:

head :created, location: person_path(@person)

head :created, location: @person

It can also be used to return exceptional conditions:

return head(:method_not_allowed) unless request.post?
return head(:bad_request) unless valid_request?
render

See Rack::Utils::SYMBOL_TO_STATUS_CODE for a full list of valid status symbols.

Source: show | on GitHub 

# File actionpack/lib/action_controller/metal/head.rb, line 19
def head(status, options = {})
  if status.is_a?(Hash)
    raise ArgumentError, "#{status.inspect} is not a valid value for `status`."
  end

  status ||= :ok

  location = options.delete(:location)
  content_type = options.delete(:content_type)

  options.each do |key, value|
    headers[key.to_s.dasherize.split("-").each { |v| v[0] = v[0].chr.upcase }.join("-")] = value.to_s
  end

  self.status = status
  self.location = url_for(location) if location

  self.response_body = ""

  if include_content?(response_code)
    self.content_type = content_type || (Mime[formats.first] if formats)
    response.charset = false
  end

  true
end