Read a line from a text file, then delete it

Question

Hello, I have a text file , filled with pipe separated URLs, like this:

http://www.example.com|http://www.example2.com|http://www.example3.com|.... 

etc.

I currently have this code to read each url from the file and pass it to a function:

<?php
  $urlarray = explode("|", file_get_contents('urls.txt'));

  foreach ($urlarray as $url) {

   function1($url);

   }

?>   

What I want to do next is, after function1() is done, delete that URL from the text file.That way, when the script is done going through all the URLs in urls.txt, this text file should be empty.

How can I achieve this?

Thanks, Rafael

Answer 1

There's no way to delete stuff from the beginning or middle of a text file without rewriting the whole thing. See here. Just go through all the URLs and then delete the file, or implode() any remaining URLs and overwrite the original file with it.

Answer 2

You could pull the first URL of the exploded list, implode it and write it back to the file:

while($urls = explode('|', file_get_contents('urls.txt'))) {

  $first_url = array_shift($urls);

  file_put_contents('urls.txt', implode('|', $urls));

  function1($first_url);
}

Are you expecting this process to be interrupted? If not, it makes more sense to simply assume that all the URLs will be processed, and blank the file when the program is complete:

foreach (explode('|', file_get_contents('urls.txt') as $url) {
  function1($url);
}

file_put_contents('urls.txt', '');