php - 当转到登录页面时，如果已经登录，则重定向到索引

Question

当用户在没有登录的情况下访问索引时，它会重定向到登录页面。

但是如果用户在已经登录的情况下试图打开登录页面，如何让系统将用户重定向到索引呢？

它是我的登录 php:

    <?php
if(isset($_POST["button_login"]))           //FUNGSI LOGIN
{ 

    $user   = $_POST["name"];
    $pass   = $_POST["password"];

    $sql_login      = "SELECT * FROM user WHERE username='$user' AND password='$pass'";
    $result_login   = $conn->query($sql_login);
    $row_login      = $result_login->fetch_assoc();
    $numrow_login   = $result_login->num_rows;

    if($numrow_login==1)
    {
        session_start();
        $_SESSION['user'] = $user;
        header('Location:index.php?');
    }
}
?>

Answer 1

您应该首先测试他们是否已经登录。最好在脚本文件的顶部session_start()

<?php
session_start();

// If user already logged in, send them to index
if ( ! empty( $_SESSION['user'] ) ) {
    header('Location:index.php?');
    exit;
}

if(isset($_POST["button_login"]))           //FUNGSI LOGIN
{ 

    $user   = $_POST["name"];
    $pass   = $_POST["password"];

    $sql_login      = "SELECT * FROM user WHERE username='$user' AND password='$pass'";
    $result_login   = $conn->query($sql_login);
    $row_login      = $result_login->fetch_assoc();
    $numrow_login   = $result_login->num_rows;

    if($numrow_login==1)
    {
        $_SESSION['user'] = $user;
        header('Location:index.php?');
        exit;
    }
}
?>