Lightweight database using Ocsipersist

For maintaining the list of user and password, we do not need the full power of a SQL database, a key/value table is sufficient. Ocsigen has such a simple table mechanism directly integrated: Ocsipersist.

We first create a table holding ocaml values:

let user_table = Ocsipersist.open_table "user_table"

Then we can easily handle the user management code:

let check_pwd name pwd =
  try_lwt
    lwt saved_password = Ocsipersist.find user_table name in
    Lwt.return (pwd = saved_password)
  with
    Not_found -> Lwt.return false

let () = Eliom_registration.Action.register
  ~service:create_account_service
  (fun () (name, pwd) -> Ocsipersist.add user_table name pwd)

let () = Eliom_registration.Action.register
  ~service:connection_service
  (fun () (name, password) ->
    match_lwt check_pwd name password with
      | true -> Eliom_reference.set username (Some name)
      | false -> Lwt.return ())