module Rack::Request::Helpers

def POST
  if error = get_header(RACK_REQUEST_FORM_ERROR)
    raise error.class, error.message, cause: error.cause
  end
  begin
    rack_input = get_header(RACK_INPUT)
    # If the form hash was already memoized:
    if form_hash = get_header(RACK_REQUEST_FORM_HASH)
      # And it was memoized from the same input:
      if get_header(RACK_REQUEST_FORM_INPUT).equal?(rack_input)
        return form_hash
      end
    end
    # Otherwise, figure out how to parse the input:
    if rack_input.nil?
      set_header RACK_REQUEST_FORM_INPUT, nil
      set_header(RACK_REQUEST_FORM_HASH, {})
    elsif form_data? || parseable_data?
      unless set_header(RACK_REQUEST_FORM_HASH, parse_multipart)
        form_vars = get_header(RACK_INPUT).read
        # Fix for Safari Ajax postings that always append \0
        # form_vars.sub!(/\0\z/, '') # performance replacement:
        form_vars.slice!(-1) if form_vars.end_with?("\0")
        set_header RACK_REQUEST_FORM_VARS, form_vars
        set_header RACK_REQUEST_FORM_HASH, parse_query(form_vars, '&')
      end
      set_header RACK_REQUEST_FORM_INPUT, get_header(RACK_INPUT)
      get_header RACK_REQUEST_FORM_HASH
    else
      set_header RACK_REQUEST_FORM_INPUT, get_header(RACK_INPUT)
      set_header(RACK_REQUEST_FORM_HASH, {})
    end
  rescue => error
    set_header(RACK_REQUEST_FORM_ERROR, error)
    raise
  end
end