什么是在购物车中包含运费报价的最佳方法？
我的网站的基本流程是
1.) User selects products
2.) User is shown cart
3.) repeat 1 and 2 until User wants to pay
4.) collect user details ( email, address where items will be shipped to )
5.) make payment via active merchant
6.) order is submitted to distributor.
我想插入一个运输信息，这样用户就可以通过Active Merchant支付他的购买费用和运输成本。
1.) User selects products
2.) User is shown cart
3.) repeat 1 and 2 until User wants to pay
4.) collect user details ( email, address where items will be shipped to )
5.) calculate the cost of shipment, add cost to cart, show to user;
6.) make payment via active merchant
7.) order is submitted to distributor.
有没有一个宝石或插件可以帮助我完成这个任务，如果没有...我该如何完成？