Farnell internally uses group IDs (or whatever they're called internally) to select for instance the named groups (passives, resistors, fuses, etc.) in the database. If you would like to view all aluminum electrolytic caps in the customer UI, you search for browse.jsp?N=202457 and it spits out all these types of components. Actually searching in the customer UI for the names of groups (e.g. typing 'Aluminium electrolytic') does not yield the same result: it searches a selection of fields, so this is not a good way of extracting information about one product group. Also note that group IDs work for all parameters: product categories, 'in stock'-flags (ID 721), manufacturers, etc. It is an extremely convenient way to quickly search and sort data. Obviously the reason why Farnell uses it.
Now, the REST API does not actually let you search for group IDs. It will only accept either component numbers (with id:[component number]) or general search terms (any:aluminium). It does not seem to accept spaces encoded in any way either, so even if I wanted to search for aluminium electrolytic capacitors using the REST API, it won't let me. When using group IDs in the id: field, the API throws exception 200003, i.e. searching for group IDs is not acceptable. That's extremely inconvenient for my application. The only way I see around this is going back to good old spidering/web crawling and making a billion requests to extract the entire Farnell database, then do my own stuff with it. I've got that working already, but it's slow as molasses and I imagine very heavy on the Farnell servers, just to do a bit of resistor sorting.
Is there any other way around this?
Edit: of course 5 minutes after posting I figure out the first part of the question, I can actually search for entire groups. I was stupid, the correct search terms are 'aluminium-electrolytic', 'fixed-value', etc. So dashes instead of spaces. This doesn't fix it completely, though. I would still like to be able to search for the other group IDs.