Question

当我第一次打开登录页面时，即使我使用正确的用户名和密码，登录页面也不会被重定向到主页。但是在第二次登录时，它被正确地重定向到主页。 login.php的代码如下所示。

<?php
session_start();
$_SESSION['login_user'] = false;
?>

其余的login.php是简单的html，登录表单数据被发送到validate.php 其中validate.php看起来像这样。

<?php
session_start();
    $username="";
    $password="";
    $usernameErr=""; 
    $passwordErr="";
    $empty=false;
    $_SESSION['login_user'] = false;
    if(isset($_POST['submit']))
    {
        if(empty($_POST['username']))
        {
            $empty=true;
            $usernameErr="Username is empty. Please try again";
        }
        else 
            {
                $username=$_POST['username'];
            }
        if(empty($_POST['password']))
        {
            $empty=true;
            $passwordErr="Password is empty. Please try again";
        }
        else 
            {
                $password=$_POST['password'];
            }
        if(!$empty)
        {
            $servername="myxor.in.mysql";
            $dbusername="myxor_in";
            $dbpassword="srikanth177";
            $dbname="myxor_in";
            $conn=new mysqli($servername, $dbusername, $dbpassword, $dbname);
            if($conn->connect_error) 
            {
                die("Connection failed: " . $conn->connect_error);
            }
            $sql = "SELECT firstname,package,username,password FROM users WHERE username='$username'";
            $result = $conn->query($sql);
            if (($result->num_rows) > 0) 
            {
                $row = $result->fetch_assoc();
                if($username === $row['username']) 
                    {
                        if($password === $row['password'])
                        {
                            $_SESSION['fname'] = $row['firstname'];
                            $_SESSION['pack'] = $row['package'];
                            //$_SESSION['login_user'] = $username;
                            $_SESSION['login_user'] = true;
                            header('Location: http://www.myxor.in/home.php');
                            exit;
                        }
                        else
                        {
                            $passwordErr = "Invalid Password. Please Try Again";
                        }
                    }
            } else
            {
                $usernameErr = "Invalid Username. Please Try Again";
            }
        }
    }
    else echo "submit not set";
    echo $usernameErr;
    echo "<br>";
    echo $passwordErr;
?>

为什么登录页面第一次没有运行的任何建议（请注意，当我第二次登录时，它被正确地重定向到所需的home.php）

Answer 1

您应该在登录页面上打印会话变量。像这样：

var_dump($_SESSION);

因此，当您输入登录信息并且在第一次尝试时未重定向时，您将看到是否正在设置值。这是迈出的第一步。然后，您将更好地了解需要在文件中更改的内容。

Answer 2

尝试使用以下代码。

<?php
    session_start();
    $username="";
    $password="";
    $usernameErr=""; 
    $passwordErr="";
    $empty=false;
    $_SESSION['login_user'] = false;
    if(isset($_POST['submit']))
    {
        if(empty($_POST['username']))
        {
            $empty=true;
            $usernameErr="Username is empty. Please try again";
        }
        else 
        {
            $username=$_POST['username'];
        }
        if(empty($_POST['password']))
        {
            $empty=true;
            $passwordErr="Password is empty. Please try again";
        }
        else 
        {
            $password=$_POST['password'];
        }
        if(!$empty)
        {
            $servername="myxor.in.mysql";
            $dbusername="myxor_in";
            $dbpassword="srikanth177";
            $dbname="myxor_in";
            $conn=new mysqli($servername, $dbusername, $dbpassword, $dbname);
            if($conn->connect_error) 
            {
                die("Connection failed: " . $conn->connect_error);
            }
            $sql = "SELECT firstname,package,username,password FROM users WHERE username='$username'";
            $result = $conn->query($sql);
            if (($result->num_rows) > 0) 
            {
                $row = $result->fetch_assoc();
                if($username == $row['username']) 
                    {
                        if($password == $row['password'])
                        {
                            $_SESSION['fname'] = $row['firstname'];
                            $_SESSION['pack'] = $row['package'];
                            //$_SESSION['login_user'] = $username;
                            $_SESSION['login_user'] = true;
                            header('Location: http://www.myxor.in/home.php');
                        }
                        else
                        {
                            $passwordErr = "Invalid Password. Please Try Again";
                        }
                    }
            } else
            {
                $usernameErr = "Invalid Username. Please Try Again";
            }
        }
    }
    else echo "submit not set";
    echo $usernameErr;
    echo "<br>";
    echo $passwordErr;
?>

登录页面无法正常运行

2 个答案: