Question

So I am trying to implement nice meta-data concept in my application. Basically, I store some details in XML format in a single column in the database but in my application I can access them through a Hash.

def extra_info=(data)
    data = {} unless data.is_a?(Hash)
    self[:extra_info] = data.to_xml(:dasherize => false)
end

def extra_info
   Hash.from_xml(self[:extra_info])['hash']
end

Rather simple, following what I read on a blog post on the subject.

However, now my application throws an error:

ERROR ArgumentError: wrong number of arguments (1 for 0)
.../app/models/users/usage.rb:35:in to_xml

So I tried this

def extra_info=(data)
    data = {} unless data.is_a?(Hash)
    self[:extra_info] = data.to_xml
end

And still I get the same error! Anyone faced this issue? What’s wrong?

Answer 1

Turns out this was a backward compatibility issue with the version of builder included in Rails. Problem with REE only.

From elisehuard on github:

in Ruby 1.8.7 arity of method to_xs is 0 – in 1.9.2 it takes encoding

Criminal. Anyway, much thanks to her for the fix, which can be found here.