Decorate an Iterator in PHP - enable skipping

Question

I have a class that is basically a decorator for PHP's DirectoryIterator. Each file's contents are processed by the class and then returned by the current() method. Currently, when the file is a dot file or the file cannot be processed, I return false from the current() method. But I would rather like to skip the dot- and unprocessable files, and only return processed data.

P.S. The code below is a simplified example. I don't want to pre-process all files in the constructor.

class Pages implements \Iterator
{
    public function __construct(string $path)
    {
        $this->di = new \DirectoryIterator($path);
    }

    public function rewind() {
        return $this->di->rewind();
    }

    public function current() {
        $file = $this->di->current();
        if($file->isDot()) {
            return false;
        }
        $content = file_get_contents($file->getPathName());
        if($content === 'Cannot be processed!') {
            return false;
        }
        return $content;
    }

    public function key() {
        return $this->di->key();
    }

    public function next() {
        return $this->di->next();
    }

    public function valid() {
        return $this->di->valid();
    }
}

Answer 1

You can greatly simplify the code of your own answer by extending the already existing abstract PHP class FilterIterator :

class DirectoryFilterIterator
  extends FilterIterator
{
  public function __construct(string $path) {
    parent::__construct(new DirectoryIterator($path));
  }

  public function accept() : bool {
    $current = parent::current();
    // let's not only ensure it's not a dot but that it's an actual readable file
    if(!$current->isFile() || !$current->isReadable()) {
      return false;
    }
    else {
      $contents = file_get_contents($current->getPathname());
      if($contents === 'Some value') {
        return false;
      }
    }
    
    return true;    
  }
}

foreach(new DirectoryFilterIterator('.') as $key => $value) {
  echo "$key -> $value\n";
}

As you can also see, instead of merely ensuring that the item is not a dot, I ensure the item is an actual readable file as I think that is a little more robust for your intentions.

---

PS: As your original intention was to create a decorator/wrapper you can of course alter the constructor of DirectoryFilterIterator to accept a DirectoryIterator instead:

public function __construct(DirectoryIterator $it) {
  parent::__construct($it);
}

...and then change the instantiation to:

foreach(new DirectoryFilterIterator(new DirectoryIterator('.')) as $key => $value) {
  echo "$key -> $value\n";
}