Auth functions

auth.ex

#Function used in auth
#1>Save the user id in session and current_user in  conn.assign which will exposed as @current_user for all template

#Deliver pass port to user, user will carry the :user_id in next request
def deliver_passport_to_user(conn,user) do
    conn
    |>assign(:current_user, user)
    |>put_session(:user_id,user.id)
    |>configure_session(renew: true) #Renew the session to keep our safe
end

#2>Try to identify the real user, we will use plug module and plug it within the plug pipeline
defmodule Blog.Auth do
    import Plug.Conn

    def init(ops) do
        ops
    end

    def call(conn, ops) do
        user_id = get_session(conn,:user_id)
        IO.puts "user ID #{user_id}"
        current_user = user_id && Blog.Repo.get(Blog.User, user_id)
        assign(conn,:current_user, current_user)
    end
end

pipeline :browser do
    plug :accepts, ["html"]
    plug :fetch_session
    plug :fetch_flash
    plug :protect_from_forgery
    plug :put_secure_browser_headers
    plug Blog.Auth
end

#3, We will do check in different controler by define check funcion and plug it
defp auth(conn, _params) do
    if conn.assigns.current_user do
      conn
    else
      conn
      |>put_flash(:error, "you must login")
      |>redirect(to: page_path(conn,:index))
      |>halt() #Then next plug will pass through conn and will not handle it
    end
end

plug :auth when action in [:index, :show]

#4 Log out, use will leave and the system will get back the pass port to the user
def recycle_passport_back(conn) do
  conn
  |>configure_session( drop: true)
  |> redirect(to: page_path(conn,:index))
end
#Summary, all there function are plugs, we plug them to the whole plug pipeline to implement our function