Changing text in file that generates HREF attribute in HTML with PHP - php

Question

I need to be able to change text in a text file that is used to generate an HREF attribute of a link in my page through a form (i.e. the user puts the link into form and the link in HTML will change). So far I made that form and one PHP script. It is working, except that it won't just change that HREF attribute but it's making a whole new link (i.e. <img src="web/assets/images/youtube.png" alt="YT" width="42" height="42" border="0">) in the HTML.
Its working like that - when you put link into form, that script will write that link into the TXT file, then on that page where I need to have that HREF is another script that takes out link from a text file. Here is the PHP:
<?php
$subor = #file('youtube.txt');
$lines = sizeof($subor);
$count = $lines/1;
for ($i = 0; $i < $count; $i++)
{
?>
<a href="<?php echo ($subor[$i * 1 + 0]) ?>"><img
src="web/assets/images/youtube.png" alt="YT" width="42" height="42"
border="0"></a>
<?php
}
?>
And this is script that is writing the link from form into the text file:
<?php
$myFile = "youtube.txt";
if(isset($_POST['flag']) && !empty($_POST['flag'])) {
$fileWrite = $_POST['flag'] . "\n";
}
if($fileWrite) {
$fh = fopen($myFile, "a") or die("can't open file"); //Make sure you have permission
fwrite($fh, $fileWrite);
fclose($fh);
exec('/your/command /dev/null 2>/dev/null &');
}
?>
<?php
header( 'Location: http://kraj.com/home.php' ) ;
?>
So how to edit that code so it won't create another but it will change the href inside that one ?

Answer 1

Mode parameter
So how to edit that code so it wont create another but it will change href inside that one ?
Change the second parameter (i.e. mode) passed to fopen() to 'w'. That way the pointer will be placed at the beginning of the file, instead of having the pointer at the end of the file (for appending).
$fh = fopen($myFile, "w") or die("can't open file"); //Make sure you have permission
See a demonstration of this in this playground example.
File_put_contents()
A simpler technique would be to use file_put_contents(). Then the following three lines
$fh = fopen($myFile, "a") or die("can't open file"); //Make sure you have permission
fwrite($fh, $fileWrite);
fclose($fh);
could be replaced with:
$numberOfBytesWritten = file_put_contents($myFile, $fileWrite);