8
Julia, 411 382 367 355 bytes
It's quite long but I'm very pleased that it works!
using Requests
n->(R(t)=readall(get(t));G(t)=JSON.parse(R("http://api.stackexchange.com/2.2/questions/$t?site=codegolf"))["items"];j=G(n)[1];d=parse(Int,match(r"<span \S+n (\d+)",R("http://codegolf.xyz/posts/$n/r...