WordPress Generate Password / Hash Password

A while back I had to migrate a legacy application’s user information into a WordPress MU application, transferring user accounts from the old platform to the new.

I needed to figure out a way to create 10,000+ WP users based on the old information. The old application stored the user passwords in clear/plain text, WP one-way encrypts passwords. Turns out its pretty easy to create the necessary data in wp_users and wp_usermeta, if you can figure out how to hash the password so WP understands everything.

The code below is a sort-of test harness that shows how to update an existing WP user and set their password to a known value.

require_once('/usr/local/apache/htdocs/next.sloanreview.com/wp-includes/class-phpass.php');

# get the new user password
$password = 'foo';
# find the user's WP id (wp_users.ID)
$user_id = 1;

change_user_password($password, $user_id);

function change_user_password($password=false, $user_id)
{
    $wp_hasher = new PasswordHash(8, TRUE);
    $password = $wp_hasher->HashPassword($password);
    if(is_numeric($user_id)) {
        $sql = "UPDATE wp_users SET user_pass = '$password' WHERE ID = $user_id LIMIT 1;";
        # then connect to the DB and execute mysql_query($sql)
    }
}