Just got a work to pull product RSS feed by category and tags from a Woocommerce website. Actually woocommerce has built in the RSS feed in the plugin, you just need to know how to access. So i write this post as a note for myself and for everyone that is looking for this. Hope this helps.
To show Woocommerce product RSS use the follow URL:-
http://www.yourdomain.com/?feed=rss2&post_type=product
To show Woocommerce product RSS by product category:-
http://www.yourdomain.com/?feed=rss2&post_type=product&product_cat=general
To show Woocommerce product RSS by product tags:-
http://www.yourdomain.com/?feed=rss2&post_type=product&product_tag=tag1
To show Woocommerce product RSS by product category and tags:-
http://www.yourdomain.com/?feed=rss2&post_type=product&product_tag=tag1&product_cat=general
To show Woocommerce product RSS by product category and multiple tags:-
http://www.yourdomain.com/?feed=rss2&post_type=product&product_tag=tag1,tag2&product_cat=general