重定向到 php 文件的按钮

Question

当我按下 'continue' 按钮时，我被重定向到表单的 php 函数文件 ( localhost/install/hamburgher.php )，但是必须检查代码是否正确，否则会显示错误。

hamburgher.php（点击按钮的功能）：

<?php 
session_start();

// connect to database
$db = mysqli_connect('localhost', 'root', '');
mysqli_select_db($db,"licensecode");


// escape string
function e($val){
    global $db;
    return mysqli_real_escape_string($db, trim($val));
}

$errors = array(); 

function display_error() {
    global $errors;

    if (count($errors) > 0){
        echo '<div class="alert alert-danger">';
            foreach ($errors as $error){
                echo $error .'<br>';
            }
        echo '</div>';
    }
}

if (isset($_POST['btn_lic']) && $_POST['btn_lic'] == 1)) 
{
    checkkey();
}
else
{
    array_push($errors, "License key is invalid.");
}

// USER
function checkkey(){
    global $db, $username, $errors;

    // grap form values
    $key = e($_POST['key-get']);
    // make sure form is filled properly
    if (empty($key)) {
        array_push($errors, "A license key is required.");
    }

    // attempt login if no errors on form
    if (count($errors) == 0) 
    {
        $password = md5($password);

        $query = "SELECT * FROM licenses WHERE code='$key' LIMIT 1";
        $results = mysqli_query($db, $query);

        if (mysqli_num_rows($results) == 1) 
        { // found
            // check
            $keycode = mysqli_fetch_assoc($results);
            if($keycode['expired'] == 1)
            {
                array_push($errors, "This license has expired.");
            }
            else
            {
                header('location: step_4.php');
            }
        }
        else 
        {
            array_push($errors, "License key is invalid.");
        }
    }
    else {
            array_push($errors, "Some errors there.");
    }
}

表单文件 - step_3.php:

<?php

        include('hamburgher.php');
        require_once("settings.inc");    

        if (file_exists($config_file_path)) {        
        header("location: ".$application_start_file);
            exit;
      } 

    ?>
    <!DOCTYPE html>
    <html lang="en">
    <head>
    <title><?php echo $application_name;?> Instalation Wizard - 3</title>
    <link rel="icon" href="images/brand/favicon.png" type="image/x-icon" />
    <link rel="stylesheet" type="text/css" href="styles/basic.css">
    <link href="https://fonts.googleapis.com/css?family=Muli&display=swap" rel="stylesheet">
    <link rel="stylesheet" type="text/css" href="styles/bootstrap.min.css">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    </head>


    <body>
    <center>
    <div class="card">
      <img src="../images/brand/logo_wide.png" alt="Thos Host Complete Solutions">
      <form method="post" action="hamburgher.php">
      <input type="hidden" name="submit" value="step2" /> 
        <div class="container">
          <b><div style="font-family: 'Muli', sans-serif;">Step 3: Insert your license key</div></b><br>
          <div class="form-group">
            <label for="key-get" style="margin-right: 80%">Code:</label>
            <input type="text" class="form-control" name="key-get" placeholder='38904ADSUFH8ADS7FH8ASHFASHF8ASHUFHA8SUFHU8ASHF8UHA' size="30">
          </div>
        </div>
        <?php echo display_error(); ?>
        <span class="step_active" >1</span>
        <span class="step_active">2</span>
        <span class="step_active">3</span>
        <span class="step_inactive">4</span>
        <span class="step_inactive">5</span>
        <button type="submit" class="button button_black" name="btn_lic" value="1" style="margin-left : 60%; color: white; text-decoration: none; font-family: 'Muli', sans-serif;"><b>Continue</b></button>
      </form><br>
    </div>
    </center>

    <?php include_once("footer.php"); ?>   

    </body>



    </html>

如果出现以下情况，代码必须显示错误： - 输入代码为空； - 输入代码已过期； - 输入代码不存在；

显示错误时，页面必须相同，但页面上有<?php echo display_error(); ?>，就会出现错误信息。

如果代码在数据库中找到并且未过期，您必须在页面 step_4.php 上重定向

我知道，我知道，我会修改代码以避免 SQL 注入，这是测试代码。

谢谢。

Answer 1

解决问题的最快方法是将代码从 hamburgher.php 移至 step_3.php，然后删除表单的操作，使其返回同一页面。

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