Question

A ‘product’ has many ‘parallel_products’:

class Product < ActiveRecord::Base
  has_many :parallel_products, :class_name => "Product", :foreign_key => "master_product_id"
end

In the controller I add the ‘parallel_products’ column to the list view:

class ProductsController < ApplicationController
  active_scaffold :product do |config|
    config.list.columns = [ :parallel_products ]
  end
end

This gives me a ActiveScaffold generated link in the list view to view, create and edit parallel products of the selected product.

So far so good.

Now, I want to specify this ‘parallel_products’ link in the helper instead. No changes to the link itself, it should be exactly as the ActiveScaffold generated link. The reason is that I need to add a condition, so that the link is only shown under certain circumstances.

The ActiveScaffold generated link looks like this in the log:

Started GET "/products?assoc_id=6&association=parallel_products&eid=products_6_parallel_products&parent_scaffold=products&adapter=_list_inline_adapter" for 172.16.99.11 at 2012-03-05 09:37:45 +0100
  Processing by ProductsController#index as JS
  Parameters: {"assoc_id"=>"6", "association"=>"parallel_products", "eid"=>"products_6_parallel_products", "parent_scaffold"=>"products", "adapter"=>"_list_inline_adapter"}

My best proposal for the ActiveScaffold has_many relation link in the helper is:

link_to("link text", :controller => "products", :assoc_id => record.id, :association => "parallel_products", :eid => "products_#{record.id}_parallel_products", :parent_scaffold => "products", :adapter => "_list_inline_adapter")

This gives me in the log:

Started GET "/products?adapter=_list_inline_adapter&assoc_id=6&association=parallel_products&eid=products_6_parallel_products&parent_scaffold=products" for 172.16.99.11 at 2012-03-05 09:39:38 +0100
  Processing by ProductsController#index as HTML
  Parameters: {"adapter"=>"_list_inline_adapter", "assoc_id"=>"6", "association"=>"parallel_products", "eid"=>"products_6_parallel_products", "parent_scaffold"=>"products"}

My link does not work, but it seems to be very close. Only difference is that the generated link state ‘ProductsController#index as JS’ and my syntax state ‘ProductsController#index as HTML’.

What is the correct ActiveScaffold syntax for making a ‘has_many’ relation list view link in the helper?

Answer 1

Thanks to Sergio Cambra for helping to solve this.

This is the syntax for a ‘has_many’ association link if placed in the helper:

link_to("link text", {:controller => "products", :association => "parallel_products",
  :parent_scaffold => "products", :product_id => record.id}, :class => 'index as_action',
  :id => "as_products-index-parallel_products-#{record.id}-link",
  :remote => true, :data => {:position => :after, :action => 'index'})

To answer the question in full, this is how it can be implemented to exactly replace the autogenerated AS association link:

def parallel_products_column(record)
  if product.parallel_products.blank?
    link_text = "-"
    css_class = "index as_action empty"
  else
    link_text = product.parallel_products[0...3].map{ |p| p.name }.join(", ")
    if product.parallel_products.length > 3
      link_text += ", … (#{product.parallel_products.length})"
    end
    css_class = "index as_action"
  end
  link_to(link_text.html_safe, {:controller => "products", :association => "parallel_products",
    :parent_scaffold => "products", :product_id => record.id}, :class => css_class,
    :id => "as_products-index-parallel_products-#{record.id}-link",
    :remote => true, :data => {:position => :after, :action => 'index'})
end

You will need a small ‘hack’ for the css ’empty’ class, example:

.active-scaffold a.empty {
  display: block;
  text-align: center;
}

Note:
This is for Rails/AS 3.1 or newer.