PHP fwrite chunks to video file

I have a very large video file and I am sending it in chunks using dropzone js, I can see the chunks are getting sent to my php code in the correct order and I am able to create the file from the first chunk, but when I try to fwrite to the file from other chunks, nothing happens and the file size of my video is 0 bytes when I am expecting 27.7MB, what am I doing wrong?

//Check if file exists
        if(file_exists($uploadPath . $uploadedFiles['videos']->getClientFilename())) {
          //if yes, add onto the file
          $file = fopen($uploadPath . $uploadedFiles['videos']->getClientFilename(), "w");
          //$chunk = fread($uploadedFiles['videos'], 1024);
          fwrite($file, $uploadedFiles['videos']->getStream()->getContents());
          fclose($file);

        }
        else
        {
          //if no, create the file from first chunk
          $uploadedFiles['videos']->moveTo($uploadPath . $uploadedFiles['videos']->getClientFilename());
        }

>Solution :

You should use fopen in mode a.

$file = fopen($uploadPath . $uploadedFiles['videos']->getClientFilename(), "a");

https://www.php.net/manual/en/function.fopen.php

The mode w clears the whole file and set a new content. The mode a appends a content at the end.