Question

Because of PHP’s unlink() not supporting exceptions natively, I’m making a wrapper function for it. It should throw a FileNotFoundException if, well, the given file could not be deleted because it doesn’t exist.

For this, I need to determine whether the error thrown by unlink() was caused by a missing file or something else.

This is my test version for a custom delete function:

public function deleteFile($path){
    set_error_handler(function($errLevel, $errString){
        debug($errLevel);
        debug($errString);
    });
    unlink($path);
    restore_error_handler();
}

For $errLevel and $errString I get 2 (E_WARNING) and unlink(/tmp/fooNonExisting): No such file or directory

A rather bold approach would be like this:

if( strpos($errString, 'No such file or directory') !== false ) {
    throw new FileNotFoundException();
};

Question 1: How much can I rely on the error string being the same across different PHP versions? Question 2: Is there a much better way?

Answer 1

I would simplify the code:

public function deleteFile($path){

    if (!file_exists($path) {
        throw new FileNotFoundException();
    }else{
        unlink($path);
    }

    if (file_exists($path) {
        throw new FileNotDeleted();
    }
}

Then you don’t have to catch the $errstr and do complicated error catching. And it will work down to PHP 4 when exceptions were introduced.