Empty POST method - php

Question

I am totally new in PHP and i have problem with posting data. I try to post data and write it in txt file. I already increase my post max size in php.ini. I use XAMPP
<form action="forms/save_news.php" method="post" role="form">
<div class="form-group">
<input type="text" name="date" class="form-control" id="date" placeholder="Дата" data-rule="minlen:10" data-msg="Моля въведете дата" />
<div class="validate"></div>
</div>
<div class="form-group">
<input type="text" class="form-control" name="title" id="title" placeholder="Заглавние"/>
<div class="validate"></div>
</div>
<div class="form-group">
<textarea class="form-control" name="data" rows="5" data-rule="required" data-msg="Моля въведете съдържание" placeholder="Новина"></textarea>
<div class="validate"></div>
</div>
<div class="text-center"><button type="submit">Запиши</button></div>
</form>
And my PHP code is:
<?php
if(isset($_POST['date'])) {
$date = $_POST['date'];
$fp = fopen('data.txt', 'a');
fwrite($fp, $date);
fclose($fp);
}
?>

Answer 1

My first guess would be a permission issue. What I would do to troubleshoot this is to turn on error reporting in your PHP script. Try the following code:
<?php
error_reporting(E_ALL);
ini_set("display_errors", 1);
if (isset($_POST('date')) {
$date = filter_var($$_POST['date'], FILTER_SANITIZE_STRING);
$fp = fopen('data.txt', 'a');
fwrite($fp, $date);
fclose($fp);
}
?>
Post another request from your form and see what appears in the browser. The errors that are reported should tell you where the problem is, but if you aren't positive how to fix the errors.
Now, all that said, be sure to never trust data sent from a web form. For simply testing purposes, you can do what you are doing, but I would not recommend getting into the habit since it can breed complacency. Note the change I made to the line that assigns the value of the form field to the $date variable. It uses a filter_var function to sanitize the string. There are plenty of combinations, and it is best to understand exactly how you are going to use the data, eventually to choose the correct filter(s).

Answer 2

You may consider an extra check. For example, if $_POST['date'] contained an empty string, it would pass isset() and would still append this to the Text file.
PHP Version is also a consideration here.
Try:
<?php
if(isset($_POST['date']) && !empty($_POST['date'])) {
$date = $_POST['date'];
if (is_writable('date.txt'){
$fp = fopen('date.txt', 'a');
if(fwrite($fp, $date) === FALSE){
echo "Cannot write to file";
exit;
}
fclose($fp);
} else {
echo "The file is not writable.";
}
}
?>
Also, this script assumes that date.txt and save_news.php reside in the same folder path. Is date.txt in forms folder? If it is not you will want to ensure that the script can reach the file and there are proper permissions for XAMPP and PHP to Read, Write to this file.
If date.txt is elsewhere, maybe in the parent, use:
$fp = fopen('../date.txt', 'a');
If PHP has decided that filename specifies a local file, then it will try to open a stream on that file. The file must be accessible to PHP, so you need to ensure that the file access permissions allow this access. If you have enabled open_basedir further restrictions may apply.
https://www.php.net/manual/en/function.fopen.php