Scrapy Spider to repport stock from e-commerce website

Hi, I need a spider to scrap a e-commerce website and report number of products on stock once everyday at 00:00 The spider also must return with the product price. The website that need to be scrapt don't show number of products on stock, but it shows if a model is on stock or not. The way to check the stock number, is by adding iteamt to the shopping cart. If you ad 3 items, and there only are two on stock, then you get a messeage that there are not that many products on stock. In princeple the site that need to be scraped, works like this site: [login to view URL], just with out telling directly how many products there are on stock. You need to have done this before if you want the task, so show me a case and an e-commerce site where you have done it before. If you are interested, send me a message, and I will let you know what online shop it is that need to be scraped