如何制作带有自动重定向的登录页面？

Question

For example:

When I type gmail.com it redirects me to following link

https://accounts.google.com/signin/v2/identifier?service=mail&passive=true&rm=false&continue=https%3A%2F%2Fmail.google.com%2Fmail%2F&ss=1&scc=1&ltmpl=default&ltmplcache=2&emr=1&osid=1&flowName=GlifWebSignIn&flowEntry=ServiceLogin

Then when I am done logging in, it redirects me to following link

https://mail.google.com/mail/u/0/#inbox

My question is how can I do this on my website. I have the following on any page where the user needs to be logged in.

 session_start();
 require_once 'dbconnect.php';

 // if session is not set this will redirect to login page
 if( !isset($_SESSION['user']) ) {
  header("Location: index.php");
  exit;
 }

So how can I change this code to let the login page know where to redirect after a successful log in?

I have the following on my login page.

ob_start();
 session_start();
 require_once 'dbconnect.php';

 // it will never let you open index(login) page if session is set
 if ( isset($_SESSION['user'])!="" ) {
  header("Location: home.php");
  exit;
 }

How can I change this to redirect to the page?

Answer 1

First step make GET url the current page

$actual_link = (isset($_SERVER['HTTPS']) ? "https" : "http") . "://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";

if you used link make sure the link is

echo '<a href="login.php?q='.$actual_link.'">Login</a>';

Make file login.php for check login

session_start();
require_once 'dbconnect.php';

$gotopage = $GET_["q"];

if(!isset($_SESSION['user'])) //Check if error or not isset login and redirects to index.php
{
    header("Location: index.php");
}
else if(isset($_SESSION['user'])) //Check if success login and redirects to home.php
{
    header("Location:".$gotopage);
}

Answer 2

I have found using cookies is easier. I created a cookie with user address before sent to login page, then redirected them back after the completion of login page.