Interesting Things

• Radio buttons behave strangely when they have no ‘value’ attribute. If you had a form containing a tag like this:

<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.

• Watch out for old middleware that expects the :body method of a Rack::Response to 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.