link_to in rails models - ruby-on-rails

if a user has not signed in and visits localhost:3000/projects, this error occurs undefined method `projects' for nil:NilClass
I want to change it so it will be redirected to sign_in page. But using something like
if signed_in?
#projects=current_user.projects
else
link_to 'Please sign in first' ,signin_path
end
will raise errors
This is how the SessionsHelper looks like
module SessionsHelper
def sign_in(user)
remember_token = User.new_remember_token
cookies.permanent[:remember_token] = remember_token
user.update_attribute(:remember_token, User.digest(remember_token))
self.current_user = user
end
def signed_in?
!current_user.nil?
end
def current_user=(user)
#current_user = user
end
def current_user
remember_token = User.digest(cookies[:remember_token])
#current_user ||= User.find_by(remember_token: remember_token)
end
def sign_out
current_user.update_attribute(:remember_token,User.digest(User.new_remember_token))
cookies.delete(:remember_token)
self.current_user = nil
end
end
and here is my ApplicationController
class ApplicationController < ActionController::Base
protect_from_forgery with: :exception
include SessionsHelper
end
class ProjectsController < ApplicationController
def index
#projects=Project.all
end
end

if current_user
#projects = current_user.projects
else
redirect_to signin_path, notice: "Please sign in first"
end
Also it is common practice to define current_user method in application_controller.rb.

Related

NoMethodError While Doing Hartl's RailsTutorial

I'm running into a NoMethodError while working through Hartl's Rails Tutorial. This error started showing up in chapter 11. Not sure where to track the problem back to. This is the error message:
NoMethodError in StaticPagesController#home undefined method `signed_in?' for #<StaticPagesController:0x007fa1b44a4ab8>
Rails.root: /Users/dbk/projects/apster
Application Trace | Framework Trace | Full Trace
app/controllers/static_pages_controller.rb:4:in `home'
And here's the code from my StaticPagesController:
class StaticPagesController < ApplicationController
def home
if signed_in?
#micropost = current_user.microposts.build
#feed_items = current_user.feed.paginate(page: params[:page])
end
end
end
Here's my ApplicationController:
class ApplicationController < ActionController::Base
# Prevent CSRF attacks by raising an exception.
# For APIs, you may want to use :null_session instead.
protect_from_forgery with: :exception
include SessionsHelper
end
Here's my sessions helper file:
module SessionsHelper
def sign_in(user)
session[:user_id] = user.id
end
def remember(user)
user.remember
cookies.permanent.signed[:user_id] = user.id
cookies.permanent[:remember_token] = user.remember_token
end
def current_user
if (user_id = session[:user_id])
#current_user ||= User.find_by(id: session[:user_id])
elsif (user_id = cookies.signed[:user_id])
user = User.find_by(id: cookies.signed[:user_id])
if user && user.authenticated?(cookies[:remember_token])
log_in user
#current_user = user
end
end
end
def logged_in?
!current_user.nil?
end
def forget(user)
user.forget
cookies.delete(:user_id)
cookies.delete(:remember_token)
end
def sign_out
forget(current_user)
session.delete(:user_id)
#current_user = nil
end
def redirect_back_or(default)
redirect_to(session[:return_to] || default)
session.delete(:return_to)
end
def store_location
session[:return_to] = request.url if request.get?
end
end
A NoMethodError means exactly that. A method that does not exist, or is not loaded, was called. This happens because you called your method logged_in? in SessionsHelper.
def logged_in?
!current_user.nil?
end
But you are calling signed_in? in StaticPagesController, which does not exist, and hence the error.
def home
if signed_in?
# ...
end
end

undefined method `update_attribute' for nil:NilClass

I am able to create users and sign in, however when I sign out I receive the following (although the session does appear to end):
NoMethodError at /signout
undefined method `update_attribute' for nil:NilClass
This is on the sign_out method in the SessionsHelper, where current_user.update_attribute(...)
Does this mean that current_user is nil? What can I do to fix, this. I'm very new to RoR, thanks.
Here's my SessionsHelper
module SessionsHelper
def sign_in(user)
remember_token = User.new_remember_token
cookies.permanent[:remember_token] = remember_token
user.update_attribute(:remember_token, User.encrypt(remember_token))
self.current_user = user
end
def signed_in?
!current_user.nil?
end
def current_user=(user)
#current_user = user
end
def current_user
remember_token = User.encrypt(cookies[:remember_token])
#current_user ||= User.find_by(remember_token: remember_token)
end
def sign_out
current_user.update_attribute(:remember_token, User.encrypt(User.new_remember_token))
#current_user.update_attribute(:remember_token, User.new_remember_token)
cookies.delete(:remember_token)
self.current_user = nil
end
end
Here's my SessionsController
class SessionsController < ApplicationController
def new
end
def create
user = User.find_by(email: params[:session][:email].downcase)
if user && user.authenticate(params[:session][:password])
sign_in user
redirect_to user
else
flash.now[:error] = 'Invalid email/password combination' #not quite right
render 'new'
end
end
def destroy
sign_out
redirect_to 'signin'
end
end
it would be nice if you told us what the exact circumstances are that you got this error.
it's quite possible you're going to the sign-out page when you're not actually currently signed-in.
In which case - why don't you add "if signed_in?" to your action eg:
def sign_out
return unless signed_in? # you are already signed out
current_user.update_attribute(:remember_token, User.encrypt(User.new_remember_token))
cookies.delete(:remember_token)
self.current_user = nil
end
def destroy
sign_out if signed_in?
redirect_to 'signin'
end
Alternatively - do you have skip_before_action authenticate_user or similar for sign_out?
Again - to sign out, you have to be signed-in... so you can't skip the authentication action for sign-out.

Does self refer to the ApplicationController, UsersController, or SessionsController?

There are questions similar to this but none were able to help me. I am still learning rails and am making a basic user signup system. In the signin method of the SessionsHelper module, I use the self keyword.
module SessionsHelper
def sign_in(user)
remember_token = User.new_remember_token
cookies.permanent[:remember_token] = remember_token
user.update_attribute(:remember_token, User.encrypt(remember_token))
self.current_user = user
end
def current_user=(user)
#current_user = user
end
def current_user
remember_token = User.encrypt(cookies[:remember_token])
##current_user ||= User.find_by_remember_token(:remember_token) #The find_by method might not work
#current_user ||= User.where(remember_token: remember_token).first
end
def signed_in?
!current_user.nil?
end
end
I include the module in the ApplicationController class like so:
class ApplicationController < ActionController::Base
protect_from_forgery
include SessionsHelper
end
I think that means that the keyword self in the SessionsHelper module would therefore always refer to the ApplicationController class. However, shouldn't the current_user actually rrefer to the Sessions_controller? The sign_in method is also in the SessionsController and the UsersController, but based on my understanding of self, when the method is called inside these classes, it should still refer to the ApplicationController because that is where the SessionsHelper module is included. Here is the code for the UsersController:
class UsersController < ApplicationController
def new
#user = User.new
end
def create
#user = User.new(params[:user])
if #user.save
sign_in #user
flash[:success] = "Welcome to the Sample App"
redirect_to #user
else
render 'new'
end
end
end
Here is the SessionsController:
class SessionsController < ApplicationController
def new
end
def create
user = User.find_by_email(params[:session][:email].downcase)
if user && user.authenticate(params[:session][:password])
sign_in user
redirect_to user
else
flash.now[:error] = 'Invalid email.password combination'
render 'new'
end
end
end
Thanks to anyone who can help. I've been trying to understand this for hours.
#...snip
self.current_user = user
end
The self here is the class this module has been included into. So it executes the next line
def current_user=(user)
#current_user = user
end
This stores an instance variable on the controller -- the ApplicationController. Generally, all other controller inherit from the ApplicationController, so this affects the whole system.

NoMethodError in SessionsController#create (undefined method `current_user) Hartl Chapter 9

When i sign into the sample app i've made from Hartl's rail tutorial at the end of Chapter 9 i get this error. I've searched high and low but can't figure out what's probably very obvious.
NoMethodError in SessionsController#create
undefined method `current_user=' for #session....
The errors occur in these 2 files, code below
app/helpers/sessions_helper.rb:7:in sign_in'
app/controllers/sessions_controller.rb:9:increate'
app/helpers/sessions_helper
module SessionsHelper
def sign_in(user)
remember_token = User.new_remember_token
cookies.permanent[:remember_token] = remember_token
user.update_attribute(:remember_token, User.encrypt(remember_token))
self.current_user = user
end
def signed_in?
!current_user.nil?
end
def current_user
remember_token = User.encrypt(cookies[:remember_token])
#current_user ||= User.find_by(remember_token: remember_token)
end
def current_user?(user)
user == current_user
end
def sign_out
self.current_user = nil
cookies.delete(:remember_token)
end
def redirect_back_or(default)
redirect_to(session[:return_to] || default)
session.delete(:return_to)
end
def store_location
session[:return_to] = request.url if request.get?
end
end
app/controllers/sessions_controller
class SessionsController < ApplicationController
def new
end
def create
user = User.find_by(email: params[:session][:email].downcase)
if user && user.authenticate(params[:session][:password])
sign_in user
redirect_back_or user
else
flash.now[:error] = 'Invalid email/password combination'
render 'new'
end
end
def destroy
sign_out
redirect_to root_url
end
end
Take a look at listing 8.20 on http://ruby.railstutorial.org/chapters/sign-in-sign-out. It looks like you missed the step of defining the current_user= method
def current_user=(user)
#current_user = user
end

ruby on rails - sessions

I'm following this tutorial: http://ruby.railstutorial.org/
I have a problem with my sessions. Every time I login to my application, I get no session but get redirected to my user page. And create/register users works, too.
sessions_helper.rb
module SessionsHelper
def sign_in(user)
cookies.permanent[:remember_token] = user.remember_token
#current_user = user
#self.current_user = user
end
def signed_in?
#current_user != nil
#!#current_user.nil?
end
def current_user
#current_user ||= User.find_by_remember_token(cookies[:remember_token])
##current_user ||= User.find_by_remember_token(cookies[:remember_token])
end
def current_user?(user)
#current_user = user
end
def sign_out
self.current_user = nil
cookies.delete(:remember_token)
end
def store_location
session[:return_to] = request.url
end
end
session_controller.rb
class SessionsController < ApplicationController
def new
#title = "| Signin"
end
def create
user = User.find_by_email(params[:session][:email].downcase)
if user && user.authenticate(params[:session][:password])
sign_in user
redirect_to user
else
#Fehlermeldung anzeigen falls login nicht erfolgreich war
flash.now[:error] = "Invalid email/password combination"
render 'new'
end
end
def destroy
sign_out
redirect_to root_url
end
end
I see at least one mistake:
def current_user?(user)
#current_user = user
end
Should be
def current_user?(user)
#current_user == user
end
==, not =, because you should check that current_user equals some other user, not make an assignment.

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