Getting full POST data in slim framework3

i am using nginx upload module for file upload.Files are in the $_POST parameters instead of $_FILES .How can i get the post parameters via slim framework.I am using PHP 7.1.2

This is how it should look when you upload a single file via the UI

    [0] => {"file_name":"explosion.png", "content_type": "image/png", "tmp_path": "/var/www/testsite/public_html/www-api/tmp/0000000125"}
    [1] => {"file_name":"explosion.png", "sha256" : "a48a99eb7c7b47365b69caa1478e931fc35d3a79fe74a364861a84d587392c41" , "size" : "8641"}

This is what i get when i use the API

    [file] => {"file_name":"explosion.png", "sha256" : "a48a99eb7c7b47365b69caa1478e931fc35d3a79fe74a364861a84d587392c41" , "size" : "8641"}

Why i am losing the json ?

I am using  to get the API

Here is how i get the post

$allPostPutVars = $request->getParsedBody();

echo '