Sinatra Login

app.rb

require 'sinatra'
require 'mysql2'
require 'mysql2-cs-bind'

def db
  # Mysqlドライバの設定
  @db ||= Mysql2::Client.new(
    host: 'localhost',
    port: 3306,
    username: 'root',
    password: '',
    database: 'your-database',
    reconnect: true,
  )
end

def set_user
  return nil if session[:user_id].nil?
  @user = db.xquery("SELECT * From users WHERE id = ?", session[:user_id]).to_a.first
end

def login?
  !session[:user_id].nil?
end

class LoginApp < Sinatra::Base
  enable :sessions

  set :public_folder, File.dirname(__FILE__) + '/public'

  get '/' do
    set_user
    erb :index
  end
  
  get 'signup' do
    redirect '/' if login?
    
    erb :signup
  end

  post 'signup' do
    redirect '/' if login?
    
    name = params[:name]
    email = params[:email]
    password = params[:password]

    db.xquery('INSERT INTO users (name, email, password) VALUES (?,?,?)', name, email, password)
    session[:user_id] = db.last_id
    
    redirect '/'
  end
  
  get '/login' do
    redirect '/' if login?

    erb :login
  end

  post '/login' do
    email = params[:email]
    password = params[:password]

    user = db.xquery("SELECT * FROM users where email = ? and password = ?",email, password).to_a.first


    if user
      session[:user_id] = user[:id]
      redirect '/'
    else
      erb :login
    end
  end
  
  get '/logout' do
    session[:user_id] = nil
    redirect '/'
  end
end