How to prevent the page from being submitted repeatedly in the PHP flash kill system

How to prevent the page from being repeatedly submitted in the PHP flash sale system

With the rise of e-commerce, various promotional activities such as flash sales and rush sales are becoming more and more common. . When implementing the flash sale system, an important problem needs to be solved, which is the repeated submission of pages. This article will introduce how to use PHP to write code to prevent repeated submission of issues on the page, and provide some specific code examples for reference.

1. Why it is necessary to prevent repeated page submissions

In the flash sale system, users may submit orders repeatedly, resulting in one user snapping up multiple products, or one product being snapped up by multiple users. . This will not only cause a waste of resources, but also affect the experience of other users and even cause the system to crash. Therefore, preventing repeated submission of pages is the key to ensuring the normal operation of the flash sale system.

2. Use the Token mechanism to prevent repeated page submissions

The Token mechanism is a common method to prevent repeated page submissions. The specific implementation steps are as follows:

1. Generate a unique Token when the page is loaded and save it in the session.

session_start();
$token = uniqid(); // 生成唯一Token
$_SESSION['token'] = $token; // 将Token保存在会话中

2. Add a hidden field in the page form and pass the Token value to the server as the field value.

<form method="post" action="submit.php">
   <input type="hidden" name="token" value="<?php echo $_SESSION['token']; ?>">
   <!-- 其他表单字段 -->
   <input type="submit" value="提交">
</form>

3. Verify the validity of the Token on the server side.

session_start();
if ($_POST['token'] != $_SESSION['token']) {
   // Token无效，可能是重复提交
   // 处理重复提交的代码
} else {
   // Token有效，继续处理表单数据
   // 处理表单提交的代码
}

Through the above steps, we can ensure that each form submission can only use a valid Token once, thereby preventing repeated page submission issues.

3. Use verification expiration time to prevent repeated submission

In addition to the Token mechanism, using verification expiration time is also an effective method to prevent repeated submission of pages. The specific implementation steps are as follows:

1. Generate a unique verification string when the page is loaded and save it in the session.

session_start();
$expire = time() + 60; // 设置验证串过期时间为60秒后
$hash = md5(uniqid()); // 生成唯一验证串
$_SESSION['hash'] = $hash;
$_SESSION['expire'] = $expire;

2. Add the verification string and expiration time to the form.

<form method="post" action="submit.php">
   <input type="hidden" name="hash" value="<?php echo $_SESSION['hash']; ?>">
   <input type="hidden" name="expire" value="<?php echo $_SESSION['expire']; ?>">
   <!-- 其他表单字段 -->
</form>

3. Verify the validity and expiration time of the verification string on the server side.

session_start();
if ($_POST['hash'] != $_SESSION['hash'] || time() > $_SESSION['expire']) {
   // 验证串无效或已过期，可能是重复提交
   // 处理重复提交的代码
} else {
   // 验证串有效且未过期，继续处理表单数据
   // 处理表单提交的代码
}

By setting the expiration time of the verification string, we can ensure that the form is valid within a certain time range, and will be deemed invalid after the specified time.

4. Summary

When implementing the PHP flash kill system, preventing repeated submission of pages is an important security measure. This article introduces two commonly used methods to prevent repeated page submissions, namely the Token mechanism and verification expiration time. By using these methods rationally, you can effectively prevent page submission problems and improve the security and stability of the system.

(Note: The above code is just an example, the specific implementation needs to be adjusted according to actual business needs.)

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