has_many :through failed << returning false

rubyonrails-talk
1

Hi All,

I’ve got a situation where I want a has_many :through association to behave somewhat like a normal has_many when << is called on the association. ie I would like it to return false instead of throwing an exception.

With some inspiration from http://blog.hasmanythrough.com I’ve come up with,

class Container < AR:B

has_many :container_items has_many :items, :through => :container_items do

def <<( item )
  begin
    self.concat item
  rescue ActiveRecord::RecordInvalid => e
    @owner.errors.add( :item, e)
    false
  end
end

end

Is there anything that stands out as a stark issue with doing this? I would like to call owner in some other way but I have not found how to get at @owner with a method.

The join model has only timestamps in addition to the two f’keys

Any comments, insights, crits etc are welcome.

I’ve extracted this into a plugin if anyone would like to try it. I can’t make any guarantees though. http://svn.devjavu.com/liquid/has_many_through_append_fix

Cheers Daniel

2

Thanx Josh,

I was hopeing you might take a look. I’ll have a go at using an extension for this when I get home.

Cheers