redirect to requested page after login using PHP function

Question

i have a function that echo $_SESSION value in login page and store $_SERVER['REQUEST_URI'] as $_SESSION value on other page and it works fine.

But i need to call redirect_after_login function in all product page so i just added line after redirect_after_login

So my function.php file will look link this

<?php

session_start();
$key = '';

function redirect_after_login($value) {
if (!empty($value)) {
    echo $_SESSION['url'];
  } else {
      echo $_SESSION['url'] = $_SERVER['REQUEST_URI'];
  }
}

$activate_finction = $key == true ? 'Yes' : '';
$url = redirect_after_login($activate_finction);

And in login.php i added

$key .= 'login';//calling redirect function with value so it should send session value


if (isset($_POST['submit'])) {
        // login function skipped it....
            header('location:' . $url);
            exit;
        } else {
            $error[] = 'Wrong username or password or your account has not been activated.';
        }
    }

Since $key .= 'login'; has value

$activate_finction = $key == true ? 'Yes' : '';
$url = redirect_after_login($activate_finction);

Function is now called with ==true so i should receive stored value but still i get requested_url

My problem is in all page i get $_SESSION['url'] = $_SERVER['REQUEST_URI']; this value.

How do i get session value login.php and in all product pages function should store requested_url as session value.

that is what am trying to do i just call `` in `product.php` by default `$info = $user == true ? 'Yes' : ''; $url = redirect_after_login($info);` function i called here, since `$user = '';` has no value `ifelse` should store and get value — sanoj lawrence, Jan 22 '20 at 12:03
Since actually `$user .= 'login'` has a value, but not `$key`, then `$activate_finction` will be always empty. — mitkosoft, Jan 22 '20 at 12:23
@mitkosoft sorry forgot to update. by default the `function` is called without `$key` so `function` stores `requested_URL` and in `login.php` am adding a `$key .='login'`, since in login page we added a value in `key` `function` should give us `$SESSION` data instead i get `$_SESSION['url'] = $_SERVER['REQUEST_URI'];` this is the problem. — sanoj lawrence, Jan 22 '20 at 12:29
Let me guess, you are `include` function.php in your login.php? So your code `$activate_finction = $key == true ? 'Yes' : ''; $url = redirect_after_login($activate_finction);` should be placed into your `login.php` in order to call this function AFTER your `$key .= 'login';` definition. — mitkosoft, Jan 22 '20 at 12:41
@mitkosoft yes that's the problem how do i solve, only on login page i should get `session_value` — sanoj lawrence, Jan 22 '20 at 12:45

mitkosoft · Accepted Answer · 2020-01-22T15:00:12.927

I refactor the code, so here you are a complete example:

function.php:

<?php
    session_start();

    if (isset($_SERVER['HTTP_REFERER']) && basename($_SERVER['HTTP_REFERER']) != basename($_SERVER['PHP_SELF'])) {
        $_SESSION['url'] = $_SERVER['HTTP_REFERER'];
    }

    function redirect_after_login() {
        header('Location:' . $_SESSION['url']);
    }
?>

product.php:

<?php
    include "function.php";
?>
<html>
    <head></head>
    <body>
        This is <?php echo $_SERVER['PHP_SELF']; ?> file.<br><br>
        <input type="button" name="login" value="Login" onclick="location.href='login.php'">
    </body>
</html>

login.php

<?php
    include "function.php";

    if(isset($_POST['submit'])){
        if($_POST['username'] == 1 && $_POST['password'] == 1){
            //success
            $_SESSION['logged'] = 1;
            redirect_after_login();
        }else{
            //error
            $_SESSION['logged'] = 0;
            $error = 'Wrong username or password';
        }
    }else{
        unset($error);
    }
?>
<html>
    <head></head>
    <body>
        This is <?php echo $_SERVER['PHP_SELF']; ?> file.<br><br>
        <form method="post" action="login.php">
            User: <input type="text" name="username"><br>
            Pass: <input type="password" name="password"><br>
            <input type="submit" name="submit" value="Login">
        </form>
        <?php
            if(isset($error)) echo "ERROR:" .$error;
        ?>
    </body>
</html>

Some short explanations:

to test the redirect logic, you can load product.php?id=258 initially;
$_SESSION['url'] is keeping HTTP_REFERER - the page you are coming from;
login.php is calling redirect_after_login() function on successful login (currently with user:1/pass:1, just for the example)
on successful login, there is an addition SESSION variable logged which you can use further (like to hide LOGIN button onto product.php page)
on bad login, there is an error displayed, but you the user stays on login screen.
$_SESSION['url'] is overwritten every time when you are visiting a different page and only then. This prevents losing HTTP_REFERER in case of bad login (when you have an actual refresh and HTTP_REFERER becomes the page itself)

Hope this helps.

what about product.php ? how will i store `$_SERVER['REQUEST_URI']` in session — sanoj lawrence, Jan 22 '20 at 13:01
just call `redirect_after_login()` with empty value either in your `product.php` or right after function declaration in `function.php` (if you don't wanna call it in every page). — mitkosoft, Jan 22 '20 at 13:03
Yes i don't want to call in every product page, How do i do that can update the answer — sanoj lawrence, Jan 22 '20 at 13:06
Not sure what do you mean with `How do i do that can update the answer`? — mitkosoft, Jan 22 '20 at 13:08
this one `just call redirect_after_login() with empty value either in your product.php or right after function declaration in function.php (if you don't wanna call it in every page).` without call on ever page . — sanoj lawrence, Jan 22 '20 at 13:21
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/206448/discussion-between-sanoj-lawrence-and-mitkosoft). — sanoj lawrence, Jan 22 '20 at 13:29
i tested your code in `localhost` it worked but when i tried in `web-server` i get error showing `too_many_redirect` https://stackoverflow.com/questions/59972656/unable-to-redirect-after-login-in-using-serverhttp-referer-in-php — sanoj lawrence, Jan 29 '20 at 18:00

redirect to requested page after login using PHP function

1 Answers1