Question

I need to create a method which can be called so

list_of_hash_values = MyModel.values_and_links :title, "some_query_param", lambda{|id| url_for :controller => :my_model, :action => :show, :id=> id }

It gets 3 arguments: field name (as a symbol), query parameter and lambda with one parameter. And it returns hash of values and their urls. Lambda return some string value (in this case it is ulr of a model instance).

I tried to do:

class MyModel

 def values_and_links(title, query_param, lambda_exp)

   instance_values = MyModel.order(:title).where("#{title} = ?", "%#{query_param}%")
   instance_values.each do |item|
      {:hash_key1 => item.send(title), :hash_key2 => lambda_exp.call(title)} 
   end

 end
end

It’s wrong, not working.

I hope you understand what I need to accomplish. How can I do it? How can I implement method values_and_links?

Answer 1

I would use a block instead:

class MyModel
 def values_and_links(title, query_param)
   instance_values = MyModel.order(:title).where("#{title} = ?", "%#{query_param}%")
   instance_values.each do |item|
      {:hash_key1 => item.send(title), :hash_key2 => yield(title)} 
   end
 end
end

then, you can call your method like this:

list_of_hash_values = MyModel.values_and_links :title, "some_query_param" do |id|
  url_for :controller => :my_model, :action => :show, :id=> id
end

or, for ‘short’:

list_of_hash_values = MyModel.values_and_links :title, "some_query_param" {|id| url_for :controller => :my_model, :action => :show, :id=> id}