Rails has a CookieStore class:
http://api.rubyonrails.org/classes/ActionDispatch/Session/CookieStore.html
It stores the session data inside a cookie, which is protected against
manipulation by the user because it is signed. The advantage is
obviously that this kind of session store doesn't require a persistent
server-side database.
Looking at vibe.d's SessionStore interface [1], it seems impossible to
implement the same thing in vibe.d, right?
[1] http://vibed.org/api/vibe.http.session/SessionStore