We'll respond shortly.
<input type="radio" name="foo" /> (no value attribute),
and you selected that radio button, then the POST data will contain
foo=on. The default value is not an empty string, but the word “on”.
You might run into this problem using rails form helpers. If you pass a
nil value to ActionView’s
radio_button_tag method, it will render a tag without a ‘value’ attribute, so the string “on” might show up in your params.
:bodymethod of a
Rack::Responseto return a string. In newer versions of rack, the method returns an enumerable. We ran into this problem with an old version of pdfkit. It’s fixed in the new version.