Migrate line item shipping_method cache to distribution_fee/shipping_method_name

db/migrate/20130805050109_update_line_item_caching.rb

@@ -0,0 +1,41 @@
+class UpdateLineItemCaching < ActiveRecord::Migration
+
+  class SpreeLineItem < ActiveRecord::Base
+    belongs_to :shipping_method, class_name: 'Spree::ShippingMethod'
+
+    def itemwise_shipping_cost
+      order = OpenStruct.new :line_items => [self]
+      shipping_method.compute_amount(order)
+    end
+  end
+
+
+  def up
+    add_column :spree_line_items, :distribution_fee, :decimal, precision: 10, scale: 2
+    add_column :spree_line_items, :shipping_method_name, :string
+
+    SpreeLineItem.all.each do |line_item|
+      line_item.update_column(:distribution_fee, line_item.itemwise_shipping_cost)
+      line_item.update_column(:shipping_method_name, line_item.shipping_method.name)
+    end
+
+    remove_column :spree_line_items, :shipping_method_id
+  end
+
+  def down
+    add_column :spree_line_items, :shipping_method_id, :integer
+
+    SpreeLineItem.all.each do |line_item|
+      shipping_method = Spree::ShippingMethod.find_by_name(line_item.shipping_method_name)
+      unless shipping_method
+        say "Shipping method #{line_item.shipping_method_name} not found, using the first available shipping method for LineItem #{line_item.id}"
+        shipping_method = Spree::ShippingMethod.where("name != 'Delivery'").first
+      end
+
+      line_item.update_column(:shipping_method_id, shipping_method.id)
+    end
+
+    remove_column :spree_line_items, :distribution_fee
+    remove_column :spree_line_items, :shipping_method_name
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20130801012854) do
+ActiveRecord::Schema.define(:version => 20130805050109) do
 
   create_table "cms_blocks", :force => true do |t|
     t.integer  "page_id",    :null => false
@@ -364,13 +364,14 @@ ActiveRecord::Schema.define(:version => 20130801012854) do
   create_table "spree_line_items", :force => true do |t|
     t.integer  "order_id"
     t.integer  "variant_id"
-    t.integer  "quantity",                                         :null => false
-    t.decimal  "price",              :precision => 8, :scale => 2, :null => false
-    t.datetime "created_at",                                       :null => false
-    t.datetime "updated_at",                                       :null => false
+    t.integer  "quantity",                                            :null => false
+    t.decimal  "price",                :precision => 8,  :scale => 2, :null => false
+    t.datetime "created_at",                                          :null => false
+    t.datetime "updated_at",                                          :null => false
     t.integer  "max_quantity"
-    t.integer  "shipping_method_id"
     t.string   "currency"
+    t.decimal  "distribution_fee",     :precision => 10, :scale => 2
+    t.string   "shipping_method_name"
   end
 
   add_index "spree_line_items", ["order_id"], :name => "index_line_items_on_order_id"