Introduction to how to solve the problem of repeated form submission in PHP_PHP Tutorial

Introduction to how to solve the problem of repeated form submission in PHP

Repeated submission is a problem we often encounter in development. In addition to using js to prevent repeated submission of forms, we can also use php to prevent repeated submission.

Example 1

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　/*

* How to prevent repeated submission of forms in php

　*/

session_start();

　if (empty($_SESSION['ip'])) {//The first write operation, determine whether the IP address is recorded, so as to know whether to write to the database

$_SESSION['ip'] = $_SERVER['REMOTE_ADDR']; //First write, paving the way for subsequent refresh or retreat decisions

　//..........//Write to database operation

　} else {//There has been an operation after the first write, so it will no longer be written to the database

echo 'Please do not refresh and go back again'; //Write some already written prompts or other things

　}

　?>

Specific principles

　Session scope variable token to prevent.

　1. Open session:

session_start();

　2. If there is a form submission

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　if (isset($token))

The token is included in the form in hidden form.

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　3. If the form is submitted repeatedly

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　1.if ($_SESSION["token"] != $token) {

　2. // Do not allow repeated submissions, handle them here

　3. // header("location:".$_SERVER['PHP_SELF']);

　4.} else {

5. // Normal form submission, processed here

　6. // echo "Submitted";

　7.}

　4. Set token value

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　1.$token = mt_rand(0,1000000);

　2.$_SESSION['token'] = $token;

　Introduction to how to solve the problem of repeated form submission in PHP

　------Solution--------------------

Should users be allowed to submit for the second time under normal circumstances?

　------Solution--------------------

Actually I didn’t do that

Because mature projects generally separate views and forward them through routing! This will not happen!