Ingest domain seed URLs

Currently the Definitions/Create Domain UI allows to batch import domains from a file. It would be nice to be able to similarly process a list of seed URLs with the following workflow:
for each seed {
check that URL is well formed if not log it
extract the domain
if the domain is a subdomain (e.g. blah.gibberish.foo) and root domain is
not declared in the TLDs log it
if the domain does not exist in the DB create it
add the seed to the domain's default seedlist
}
Review of this workflow proposal will be welcome.