I'm trying to find out if a blueprint is a copy or not, by using the assets api. However, I cannot really find a good way.
The 1.5 Incursion update: http://www.eveonline.com/devblog.asp?a=blog&bid=917
Added BPO/BPC difference in the "singleton" virtual column, however, singleton is always 0 or 1 with the api. So no difference there.
I tried to see if it's encoded into the ItemID bits, but I found no bits that are always 1 or 0 for BPO/BPC difference. The quantity column is always 1 and not -1 or -2 as told in the blog post. So no help there.
I do have found a half solution. If the "singleton" value is 0 then it must be a new BPO from the market, so I can mark that ItemID as BPO from that point on. And I think the industry API can be used to find out if a blueprint is a copy or not while it is in production. So that can help with some caching. But it feels like a half baked solution.
Any other ideas? (Searching around finds me lots of information that it is impossible, but as main reason that they didn't want to query another table, which is no longer an issue with the 1.5 update)