PHP或Javascript-如何设置表单提交之间的最短时间 - PHP or Javascript - How do you set a minimum time between form submits

令人惊讶的是，我在internet/stackoverflow上找不到任何相关的东西，而我认为它经常被使用。

我的表单基本上是一个文件上传表单，我想设置使用Javascript或PHP（PHP首选）提交表单之间的最短时间，以保护表单免受机器人等的攻击。

我唯一能想到的就是一个cookie/会话，但它们可以被删除/清除/修改。

存储您可以使用的提交者ip：

在最短时间后过期的memcache密钥
临时文件"flag"
使用captcha让机器人的生活更加艰难

最后，我使用了一个简单的MySQLi表。

MySQLi表包含三列，

"ID"（用户的登录ID）
上传的时间（指定时间内上传的时间，默认为15分钟）
TimeLastUploaded（用户上传其第一个最大值的时间，TimesUploaded，文档）

代码：

1.函数getuploaduse（）

function getuploaduse(){
    require('connect.php'); //Connect with the MySQL database
    $theid = mysqli_fetch_array(mysqli_query($link, "SELECT COUNT(*) FROM `UploadUse` WHERE ID='"".$_SESSION['id']."'""));
    if($theid[0] == 0){
        return 'makenew'; //Make a new row
    } else {
        return mysqli_fetch_array(mysqli_query($link, "SELECT TimesUploaded,TimeLastUploaded FROM `UploadUse` WHERE ID='"".$_SESSION['id']."'"")); //Pass on TimesUploaded and TimeLastUploaded
    }
}

2.上传页面中的PHP

//Set variables
$block = 'false';
$mintime = 15; //A minimum of 15 minutes between $maxuploads
$maxuploads = 3;
$contents = getuploaduse();// [0] => TimesUploaded, [1] => TimeLastUploaded

if(isset($_POST['thetitle'])){ //If users uploads
if($contents != 'makenew'){
    if($contents[0] == $maxuploads){
        $block = (time() - $contents[1]);
        if($block < ($mintime * 60)){
            $block= 'false';
            mysqli_query($link, "UPDATE `UploadUse` SET `TimesUploaded`=1,`TimeLastUploaded`='".time()."' WHERE `ID`='".$_SESSION['id']."'"); //Reset
        } else {
            $block = $mintime - round($block / 60);
        }
    } else {
        $block = (time() - $contents[1]);
        if($block >= ($mintime * 60)){
            $block= 'false';
            mysqli_query($link, "UPDATE `UploadUse` SET `TimesUploaded`=1,`TimeLastUploaded`='".time()."' WHERE `ID`='".$_SESSION['id']."'"); //Reset
        } else {
            $increased = ($contents[0] + 1);
            mysqli_query($link, "UPDATE `UploadUse` SET `TimesUploaded`='".$increased."' WHERE `ID`='".$_SESSION['id']."'"); //Increase
            if($increased == $maxuploads){
                $block = $mintime - round($block / 60);
            } else {
                $block = 'false';
            }
        }
    }
} else {
    mysqli_query($link, "INSERT INTO UploadUse(ID,TimesUploaded,TimeLastUploaded)   VALUES('".$_SESSION['id']."','1','".time()."')");
}
//Place your upload script here and set $success to something to show your success and not the 'Maximum uploaded'
}
//Block if user doesn't upload (so when he tries to access the upload page)
if($contents != 'makenew' && $block == 'false'){
$contents = getuploaduse();// [0] => TimesUploaded, [1] => TimeLastUploaded
if($contents[0] == $maxuploads){
    $block = (time() - $contents[1]);
    if($block < ($mintime * 60)){
        $block = $mintime - round($block / 60);
    } else {
        $block = 'false';
    }
}
}

3.使用您的上传表单

<? if($block == 'false'): ?>
<!-- Your upload form here -->
<?php elseif(isset($success)): ?>
<!-- Success here-->
<?php else: ?>
<div class="alert alert-block alert-danger fade in">
    <h4>You exceeded the maximum uploads per <?php echo $mintime; ?> min.</h4>
    <p>You may upload maximum <?php echo $maxuploads ?> documents per <?php echo $mintime; ?> minutes. You have to wait for <span class="label label-danger"><span id="updatemin"><?php echo $block; ?></span> minute<? if($block > 1){echo 's';} ?></span>.</p><br />        
  </div>
<? endif; ?>

4.在我的HTML标题中（所以当用户被阻止时，它会更新剩余的分钟数）

<?php if($block != 'false'):?><meta HTTP-EQUIV="REFRESH" content="60; url=/Upload"><? endif; ?>

如果你认为这个代码有用，请投票给我（自己）的答案，因为我确实花了时间在这个代码上。（我是一个初学者，对我来说，这段代码是值得骄傲的，尤其是因为我没有使用教程或其他答案）