How to auto-login to index page after registration without going to login page ?

[yateesh]

I want users to be redirected to home page after registration without logging in again .
I searched , but didn't find a solution .
So do tell what can be done .
Thank you .


Here is my register.php

<?php
  
    require("common.php");
        
    if(!empty($_POST))
    {      
        if(empty($_POST['username']))
        {           
            die("Please enter a username.");
        }        
        
        if(empty($_POST['password']))
        {
            die("Please enter a password.");
        }        
       
        if(!filter_var($_POST['email'], FILTER_VALIDATE_EMAIL))
        {
            die("Invalid E-Mail Address");
        }
      
        $query = "SELECT 1 FROM users WHERE username = :username ";
 
        $query_params = array( ':username' => $_POST['username'] );
        
        try
        {         
            $stmt = $db->prepare($query);
            $result = $stmt->execute($query_params);
        }
        catch(PDOException $ex)
        {          
            die("Failed to run query: " . $ex->getMessage());
        }
     
        $row = $stmt->fetch();
      
        if($row)
        {
            die("This username exists . Try another .");
        }
       
        $query = " SELECT 1 FROM users WHERE email = :email ";
        
        $query_params = array( ':email' => $_POST['email'] );
        
        try
        {
            $stmt = $db->prepare($query);
            $result = $stmt->execute($query_params);
        }
        catch(PDOException $ex)
        {
            die("Failed to run query: " . $ex->getMessage());
        }
        
        $row = $stmt->fetch();
        
        if($row)
        {
            die("This email is already registered");
        }
             
        $query = "
            INSERT INTO users (
                username,
                password,
                salt,
                email
            ) VALUES (
                :username,
                :password,
                :salt,
                :email
            )
        ";
               
        $salt = dechex(mt_rand(0, 2147483647)) . dechex(mt_rand(0, 2147483647));
                
        $password = hash('sha256', $_POST['password'] . $salt);
              
        for($round = 0; $round < 65536; $round++)
        {
            $password = hash('sha256', $password . $salt);
        }
       
        $query_params = array(
            ':username' => $_POST['username'],
            ':password' => $password,
            ':salt' => $salt,
            ':email' => $_POST['email']
        );
        
        try
        {        
            $stmt = $db->prepare($query);
            $result = $stmt->execute($query_params);
        }
        catch(PDOException $ex)
        {            
            die("Failed to run query: " . $ex->getMessage());
        }
        
        header("Location: login.php");

    }
    
?>

[Dormilich]

two possibilities I know of:
- using OpenID (haven’t used it myself yet)
- providing some kind of secondary login credentials via cookies

some notes to your PHP:
- for using Exceptions with PDO you need to enable Exception handling explicitly
- you only need one try...catch block over all your PDO code
- a salt can be very conveniently applied through hash_hmac()
- there is no need for the redirect header, you can just include login.php directly