Analyze Examples of ThinkPHP's Methods to Prevent Duplicate Submissions of Forms

This article summarizes and analyzes ThinkPHP's method of preventing repeated submission of forms. Share it with everyone for your reference. The details are as follows:

Why are there duplicate forms?

During development, if a new or For the modified form, after completing the database operation in the background, we set whether to jump to other pages or return to this page. At this time, clicking the browser's back button before submitting or refreshing the page will cause the form form to be submitted repeatedly, that is, this record Will be added or modified twice.

The reason that causes the form to be submitted repeatedly is that the form submitted for the first time will be cached in the memory and will not disappear until the next time the page is submitted or the page is closed or redirected to other pages. When the self-call returns, the data in the memory is still there. At this time, the submitted code in the page can still detect the submitted value, which will cause the effect of repeated submission.

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How to solve it?

To summarize the online solutions and your own tests, you can use the following methods:

Method 1: The simplest: after submitting the page Go to another page instead of this page. For example, if your page address is

https://www.php.cn/

, then the form action address of the page can be For another processing address, if an error is returned like

<form action="{:U(&#39;User/Index/check_login&#39;)}" method="post">

, or the user clicks the back button, it will still return to the previous address, but this situation is not safe. It is also necessary to match method 2 to be safer together

Method 2:After submitting the form, the submit button turns gray/hides the submit button

This method is usually combined with method 1 What you do is use JS to dynamically monitor the user's click action, and dynamically set the button attribute to disabeld, which means it is gray and unavailable. The code is as follows:

HTML:

<form action="{:U(&#39;User/Index/check_login&#39;)}" method="post">
  
  
  

JS:

$().ready(function(){
   $("#login_btn").on('click',function(){
      $(this).attr('disabled',true);
   });
});

Method 1 Method 2 After combining, basically more than 90% of repeated submission problems can be solved, but Da Liu Here I still want to talk about the third method, which is to solve this problem once and for all on the server side

Method 3: Use a method of hiding random TOKEN values ​​for repeated submissions Judgment

First, add the following method in the project's functions.php

//创建TOKEN
function createToken() {
  $code = chr(mt_rand(0xB0, 0xF7)) . chr(mt_rand(0xA1, 0xFE)) .    chr(mt_rand(0xB0, 0xF7)) . chr(mt_rand(0xA1, 0xFE)) . chr(mt_rand(0xB0, 0xF7)) . chr(mt_rand(0xA1, 0xFE));
  session('TOKEN', authcode($code));
}
//判断TOKEN
function checkToken($token) {
  if ($token == session('TOKEN')) {
    session('TOKEN', NULL);
    return TRUE;
  } else {
   return FALSE;
  }
}
/* 加密TOKEN */
function authcode($str) {
  $key = "YOURKEY";
  $str = substr(md5($str), 8, 10);
  return md5($key . $str);
}

Fill in the following HTML code in the form page form

HTML:

<input type="hidden" name="TOKEN" value="{:session(&#39;TOKEN&#39;)}" />

Call the creatToken() method before the page is displayed to generate a token, and use checkToken() in the corresponding controller POST request to determine whether to resubmit

if(IS_POST)
{
$post_token = I('post.TOKEN');
 if(!checkToken($post_token)){
   $this->error('请不要重复提交页面',U('User/Index/login'));
 }
}

Basically , these three methods can be used together to solve the problem of repeated form submission in ThinkPHP development. Of course, some students said that you can use ThinkPHP’s token ring mechanism, which is actually simpler. TP will generate a hidden form in the form by default. Domain, then you can judge whether this hidden domain exists and whether it matches the value in the session. The principle is the same as method 3.

PS: Today I finally posted the content using Jianshu’s markdown editor. Sure enough, the markdown syntax was not covered, and the entire layout was refreshing, not bad.

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