Cannot create proper form action URL

I am doing this tutorial https://laracasts.com/series/build-project-flyer-with-me/episodes/11 but when i create form action for dropzone to upload images like this: action="/{{$flyer->zip}}/{{$flyer->street}}/photos" method="POST" class="dropzone"

my browsers received action like "http://localhost/zip/street/photos" and return 404 error. Usually i use {{url('link_to_action')}} to solve this problem but in this case i don't know how to pass value of zip and street to URL. So can someone help me to solve this problem :D Thanks in advance