title: Validation file extensions
body: <p>I am working on a Laravel/VueJS Serverless project.</p>
  <p>I am trying to whitelist/blacklist some file extensions for my AWS S3 bucket to avoid people uploading files I don't want.</p>
  <p>I use Vapor in VueJS to temporary upload files and get a key that I send to my Controller in POST method to get back the file from temporary path and move it to the final path.</p>
  <p>I have tried adding policies on my S3 bucket but I am still able to upload file extensions I should not.</p>
  <p>If you have any clue, feel free to help me !</p>
  <p>Thanks a lot !</p>