Showing users unique info when facebook authenticate , with Sinatra/ Ruby - ruby

Question

Super beginner here.
Here's what I am trying to do:
Build a basic to do list app, where User X logs in with facebook, adds some items, sees them, logs out. User Y/Z/M/etc, should be able to log in see their OWN list, add their OWN items, etc.
AKA: a standard web app where you log in to your account and see your own info.
What I have so far:
Ability to build a list, log in with Facebook and having it know your name.
However, the list stays the same whether I log in or whether my friend logs in with her account.
What I need to do, and don't know how:
I need each user to be able to create and see their own list, and be able to come back to it and still see it/ add to it, etc.
I don't even know how this is called, would this be a database of users each with their own set of data? Would the lists need to be set up so they could be stored as a chunk of data?
Does it have something to do with this :Sessions in Sinatra using Facebook authentication If so, what?
If anyone could be give me some really really basic directions as to where to go from here, any tutorials or what I should be googling for, that'd be awesome.
Here's my main piece of code (warning: it's really messy) :
require 'sinatra'
require 'data_mapper'
require 'time'
require 'rubygems'
require 'json'
require 'omniauth'
require 'omniauth-facebook'
#TODO require 'omniauth-att'
SCOPE = 'email,read_stream'
DataMapper::setup(:default, "sqlite3://#{Dir.pwd}/queue.db")
class SinatraApp < Sinatra::Base
configure do
set :sessions, true
set :inline_templates, true
set :protection, :except => :frame_options
end
class Note
include DataMapper::Resource
property :id, Serial
property :content, Text, :required => true
property :complete, Boolean, :required => true, :default => false
property :created_at, DateTime
property :updated_at, DateTime
end
class User
include DataMapper::Resource
property :id, Serial
property :uid, String
property :name, String
property :created_at, DateTime
end
###### no clue what this does ##############
DataMapper.finalize
DataMapper.auto_upgrade!
enable :session
use OmniAuth::Builder do
provider :facebook, '464630283595639','5e4c7ad43bf111c10287c981d51127a3',:scope => SCOPE, :display => "popup"
#provider :att, 'client_id', 'client_secret', :callback_url => (ENV['BASE_DOMAIN']
end
###### root ##############
get '/' do
if current_user
#notes = Note.all :order => :id.desc
#title = 'Movie Queue'
erb :home
else
' sign in with Facebook'
end
end
###### authentication ##############
["/sign_in/?", "/signup/?"].each do |path|
get path do
redirect '/auth/facebook'
end
end
get '/auth/:name/callback' do
auth = request.env["omniauth.auth"]
user = User.first_or_create({ :uid => auth["uid"]}, {
:uid => auth["uid"],
:name => auth["first_name"],
:created_at => Time.now })
session[:user_id] = user.id
redirect '/'
end
helpers do
def current_user
#current_user ||= User.get(session[:user_id]) if session[:user_id]
end
end
##list making part###
post '/' do
n = Note.new
n.content = params[:content]
n.save
redirect '/'
end
get '/:id/delete' do
n = Note.get params[:id]
if n.destroy
redirect '/', :notice => 'Note deleted successfully.'
else
redirect '/', :error => 'Error deleting note.'
end
end
get '/:id/complete' do
n = Note.get params[:id]
n.complete = n.complete ? 0 : 1 # flip it
n.save
redirect '/'
end
########## logout and error handlers #############
get '/logout' do
session[:user_id] = nil
redirect '/'
end
get '/auth/failure' do
erb "<h1>Authentication Failed:</h1><h3>message:<h3> <pre>#{params}</pre>"
end
get '/auth/:provider/deauthorized' do
erb "#{params[:provider]} has deauthorized this app."
end
get '/protected' do
throw(:halt, [401, "Not authorized\n"]) unless session[:authenticated]
erb "<pre>#{request.env['omniauth.auth'].to_json}</pre><hr>
<a href='/logout'>Logout</a>"
end
end
########## don't know what this is #############
SinatraApp.run! if __FILE__ == $0

Answer 1

Disclaimer: I don't know Datamapper, but this should get you going.
There needs to be a way to associate a note with a user. This needs a table in the database, some would call it users_notes, personally I prefer users_rel_notes, (perhaps Datamapper has a convention for this… YMMV). Anyway, the table will have a minimum of 2 columns - the user's id, and the note id. You don't need a separate table as I wrote before (I'm lacking a bit of sleep, sorry!), that would be for a many to many relationship where a user could have several notes and a note could be associated with several users. For what you have, where only the owner of a note has access to it, it requires a one to many relationship. You could add a column to the notes table to store the user id.
Then, in the User class, add an association to the Note class, it's a one to many association and in Datamapper that's a has n, e.g.
has n, :notes
Now when you have a user instance, you can (probably) call the notes for that user via:
user.notes
I see you have the helper current_user defined, so if someone is logged on you could call current_user.notes to get back all the notes for the logged in user.
Remember, when you add a note to make sure you add a record to the association table, (probably, read the link) via user.notes << my_new_note.
The session is the information you keep around to identify the user and any other little bits of info that you may recurrently need. The likelyhood is, you're just storing an id for the user, or the facebook token that identifies them, and then during a request, if it's needed then you'll look inside the cookie, grab the id, look up that user by the id and get a user instance. Session info can be stored in several ways, most often cookies but you can use anything you would use to store any other data.