Writing variables to files if file doesn't contain variable

Question

I am not sure why this doesn't work:

<?PHP
$user = $_GET['user'];
$write = $user . "\n";
if(strpos(file_get_contents("recent.txt"),$write) !== false){
    file_put_contents('recent.txt', $write, FILE_APPEND | LOCK_EX);
}
?>

What I am doing is to get the search term from a form and write it to a file. The way the original code is set up, it is only possible (as of 2014) to have 14,530,014 entries.

When the form is submitted (or ?user=SomeUser is added to the URL), nothing happens to recent.txt. Any help would be appreciated.

Answer 1

If you want to write the info if it is not contained in the file, you need to change

strpos(file_get_contents("recent.txt"),$write) !== false

to

strpos(file_get_contents("recent.txt"),$write) === false

!== false means that the file contents do contain the user you were looking for. It would return false if the string was not found.

Additionally, you may want to add a call to isset() to check if $_GET['user'] is actually set.

And depending on how large you expect this file to get, using a database to do this may be a much better (more efficient) option.