Avoiding form resubmit in php when pressing f5

2020-01-25 02:02发布

站内问答 / PHP
2008 10 5

I have the following code on my site (using php and smarty) to try and avoid a form resubmitting when I hit f5:

if ($this->bln_added == false) {
    if (isset($_POST['submit'])) {
        $this->obj_site->obj_smarty->assign('title', $_POST['tas_heading']);
        $this->obj_site->obj_smarty->assign('desc', $_POST['tas_description']);
    }
} else {
    $this->obj_site->obj_smarty->assign('title', '');
    $this->obj_site->obj_smarty->assign('desc', '');
    unset($_POST);
}

bln_added is false by default, but changes to true once the form is successfully submitted. The smarty variables title and desc are used in the template to keep the form content there in case there is a user error and they need to change what they entered.

If the form is submitted successfully it sets bln_added = true, so the second bit of code should not only clear the form fields, but also empty $_POST. But if I press f5 the post data is still there.

Any ideas?

10条回答
▲ chillily
2楼-- · 2020-01-25 02:30

Try my own one, maybe it isn't best solution (done quickly), but I've test it and it works. Tested on Chrome. Click to see how it looks BR 

 <?php 
session_start(); // Start session
?>
<html>
 <head>
  <title>
    Test
  </title>
 </head>
 <body>
   <form name="test" action="<?php echo htmlentities($_SERVER['PHP_SELF']); ?>" method="post">
   <input type="text" name="name"><br>
   <input type="submit" name="submit" value="Submit Form"><br>
  </form>

  <?php

  if(isset($_POST['submit']))
    {
     $_SESSION['name'] = $_POST['name']; //  Assign $_POST value to $_SESSION variable
      header('Location: refresh.php'); // Address of this - reloaded page - in this case similar to PHP_SELF
    } else session_destroy(); // kill session, depends on what you want to do / maybe unset() function will be enough

  if(isset($_SESSION['name']))
    {
     $name = $_SESSION['name'];

     echo "User Has submitted the form and entered this name : <b> $name </b>";
     echo "<br>You can use the following form again to enter a new name."; 
    }
  ?>
 </body>
</html>
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我只想做你的唯一
3楼-- · 2020-01-25 02:32

The solution is a pattern commonly known as Post/Redirect/Get

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啃猪蹄的小仙女
4楼-- · 2020-01-25 02:37

The best way to handle forms is to use self-submission and a redirect. Something like this:

if (isset($_POST)) {
  // Perform your validation and whatever it is you wanted to do
  // Perform your redirect
}

// If we get here they didn't submit the form - display it to them.

Using the CodeIgniter framework:

function index() {
  $this->load->library('validation');
  // Your validation rules

  if ($this->form_validation->run()) {
    // Perform your database changes via your model
    redirect('');
    return;
  }
  // The form didn't validate (or the user hasn't submitted)
  $this->load->view('yourview');
}
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家丑人穷心不美
5楼-- · 2020-01-25 02:37

It works for me if I use either header() or exit() at the end of my code, for example, after I save some data.

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