如何在Rails 3中实现“记住我”功能？

Question

What are the best practices to implement a "Remember Me" function in Rails 3 application ?

I store session information (session id + user id) in the database when user logs in, and I don't want to use any plugins at this moment.

Any pointers or code samples will be much appreciated.

Answer 1

You can just set the expiration on a signed cookie to accomplish this. (Signed cookies are tamper-proof just like the Rails-provided session cookie.)

class SessionsController < ApplicationController

  def create
    ...
    user = User.authenticate(params[:email_address], params[:password])

    if params[:remember_me]
      cookies.signed[:user_id] = { value: user.id, expires: 2.weeks.from_now }
    else
      # expires at the end of the browser session
      cookies.signed[:user_id] = user.id
    end
  end

  def destroy
    cookies.delete :user_id
  end
end 

class ApplicationController < ActionController::Base
  ...
  def current_user
    User.find(cookies.signed[:user_id])
  end     
end

Answer 2

Railscasts has an episode on achieving this as well as well as a great HOWTO on implementing those features via BDD with RSpec and Capybara .

I store session information (session id + user id) in the database when user logs in

I believe that's one approach and the casts above does the same with cookies by issuing each User account a unique authentication token.

Answer 3

Have been reading the Rails tutorial book and it has an implementation for Remember Me

You can check for some hints (The implementation may be different from yours)

http://ruby.railstutorial.org/book/ruby-on-rails-tutorial#sec:remember_me

Answer 4

This is how I implemented remember_me (the below snippet is from my example Rails app on authentication ):

class SessionsController < ApplicationController
  skip_before_filter :login_required, :only => [:new, :create]

  def new
  end

  def create
    @current_user = User.authenticate(params[:email], params[:password])

    if @current_user
      @current_user.track_on_login(request)

      if params[:remember_me]
        cookies[:remember_token] = { :value => @current_user.remember_token, :expires => 24.weeks.from_now }
      else
        cookies[:remember_token] = @current_user.remember_token
      end

      redirect_to dashboard_url, :notice => "Logged in successfully."
    else
      flash.now[:alert] = "Invalid login or password."
      render 'new'
    end
  end

  def destroy
    current_user.track_on_logout
    current_user.reset_remember_token_and_save  # can't rely on the 'save_current_user_if_dirty' after_filter here

    cookies.delete(:remember_token)
    reset_session

    redirect_to root_url, :notice => "You have been logged out."
  end
end

Answer 5

Just an example without salt:

class ApplicationController < ActionController::Base

  protected

  def signin!(user_id)
    return unless user_id
    @current_user = User.find(user_id)
    self.session_user_id = @current_user.id
    self.permanent_user_id = @current_user.id if session[:accept_remember_me]
  end

  def signout!
    self.session_user_id = nil
    self.permanent_user_id = nil
    session[:accept_remember_me] = nil
    @current_user = nil
  end

  def remember_me
    session[:accept_remember_me] = true
  end

  private

  def permanent_user_id
    cookies.signed[:permanent_user_id]
  end

  def permanent_user_id= value
    cookies.permanent.signed[:permanent_user_id] = value
  end

  def session_user_id
    session[:user_id]
  end

  def session_user_id= value
    session[:user_id] = value
  end

end