[Rails] Find object based on string value.

Hi all,

I have this method which, ideally, I would like to work in such a way as
I pass in three string values, the first is the name of the object I am
trying to instantiate, the second a string value corresponding to an
attribute for that object and finally the value that the attribute gets
updated with.

The second half of this I have working, but instantiating an object from
a string value is not working.

I have done several searches and have come up with a solution that runs
the correct query but doesn't seem to create an actual object. Here is
what I have:

params => {:model => "user", :attr => "name", "user" => { "name" =>
"John"}}

def save_update
@obj = Object.const_get(:"#{params[:model]}").find(:first,
:conditions =>
["upper(#{params[:attr]}) = ?",
params[:"#{params[:model]}"][:"#{params[:attr]}"]])

if !@obj.blank?

end
end

When I get to the line checking to make sure the object is not blank
results in failure.

I guess my question is is this even possible and does anybody have any
suggestion on how to make this work? Thanks,

-S