One of my clients is using his feed on pricerunner.co.uk, and has asked for me to set it up in such a way that he can choose which products are going to be used for the feed, as he doesn't want to pay a cost per click on items he isn't really all that interested in.

Only use this if your not wanting to use the ALL_PRODUCTS XML, as i think it will throw up errors in that one, ill explain at the end of this post why.

All i have done is use the custom feed in the Mambot (this will also work for Version 2 and 3)

Create a new category in virtuemart, i called mine "productfeed", then find the Cat ID out, using the instructions on the Mambot itself or unpublish it and republish it, as you turn it on and off, it says

Info: category_id(s) 35 was/were published.

So you can see immediately what the id is.

Whilst keeping that category unpublished (so it wont confuse your shoppers on the public end of your site), add that ID number to your custom feed admin section.

Go to into your product manager open the product you want to advertise and select the second category, by clicking using CTRL to select a second category as well as the original.

Now generate a feed by saving the mambot and refreshing the site home page. Click on the link to your custom feed, in your mambot, and you should see any products you added.

The errors i mentioned at the top of the post, is the duplicate ID number issues with Google, if there are 2 products in the feed with the same ID number, then the product wont be listed at all on Google, as it sees it as a attempt to add more than one type of that product. It could actually stop your whole feed from working completely.

You will have the same product listed in one category, and then in the "productfeed" category that we just made up, so the same ID number will be displayed twice or more.

I cant think of any solution from this apart from literally having a list of all products you want adding to the system that you manually turn on and off, but that would be almost impossible, as some clients have many hundreds of thousands of products.

So the outcome will be if your just using custom_products.xml, its great, but if your using custom for one comparison site like pricerunner, and all_products.xml for Google, then Google will fail.

I have thought about trying to add in a filter, so if a product id has already been used, it will skip any other product using that same ID on the rest of the feed. This should also fix the child product issue as well. No idea how to do this at the moment though as for it to organise the products before generating a feed with many hundreds of thousands of products maybe extremely demanding on a server.

Any other ideas?