[Rails] How to temporarily save the request URL of a user who is not logged in and return to that URL after logging in

The title is long. Here is a summary of friendly forwarding.

What is Friendly Forwarding?

It's a kind of process like "The page you requested, the page after login, but you haven't logged in yet. I'll guide you to the page you wanted to go to after logging in." Kind design that you often see. It's fine.

How do you make it?

The general flow is as follows.

• When a user who is not logged in arrives

1. Temporarily save the requested URL
2. Skip to the login screen and confirm your login
3. Revert to the requested URL

Method definition

Prepare a method (1) for temporarily saving the request and a method (3) for returning to the temporarily saved URL. This time, in sessions_helper.rb, write as follows.

helpers/sessions_helper.rb

# 1.Temporarily save the requested URL
def store_location
  session[:forwarding_url] = request.original_url if request.get?
end

# 3.Revert to the requested URL
def redirect_back_or(default)
  redirect_to(session[:forwarding_url] || default)
  session.delete(:forwarding_url)
end

Save the requested URL (request.original_url) as session [: forwarding_url] in 1. ʻIf request.get?` limits the request type to GET actions only.

3 is the process to return to the temporarily saved URL or to return to the URL specified as the default. Even if the URL does not exist||After that, the URL set in default can be entered. Also, if you keep the session information, it will be read and strange at the next login, so the URL temporarily saved with session.delete (: forwarding_url) on the second line in the method Delete.

Temporarily save the requested URL + login confirmation

Call store_location to temporarily store the URL you are trying to access. Here, I will write it together with the description to check if the logged-in user is below private of ʻusers_controller.rb`.

users_controller.rb

class UsersController < ApplicationController
  before_action :user_login_required

・
・
・

private

def user_login_required
  unless logged_in? #When not logged in
    store_location #Temporarily save the URL here!
    flash[:danger] = "Please login" #Show flash message
    redirect_to login_url #Forced to send to login page
  end
end

Revert to the requested URL

Use redirect_back_or (default) to specify the transition destination after login. It is OK if you write the following in the place where the login process is performed.

controllers/sessions_controller.rb

def create
  user = User.find_by(email: params[:session][:email].downcase)
  if user && user.authenticate(params[:session][:password])
    log_in user
    params[:session][:remember_me] == '1' ? remember(user) : forget(user)
    flash[:success] = "You are now logged"
    #Specify the redirect destination below. default uses user here, but user_Can be written like url
    redirect_back_or user 
  else
    flash.now[:danger] = 'I failed to login'
    render 'new'
  end
end

This completes the implementation! If you dare to log in after deporting from an existing URL, you will be taken to that URL. Thank you for your support.

at the end

As mentioned above, I tried to reorganize each role in my own way so that it is easy to understand at a glance. I hope you find it helpful.

I referred to the following for implementation. Thank you very much.

-10.2.3 Friendly Forwarding (Rails Tutorial) -The most suitable technical blog in the world --Friendly forwarding