PHP: $_FILES returns empty

I wish this help you Okay, I solved my problem. I enabled error_resporting() and because any reason the permissions weren't set. Now they are 777 and I can move the files.

hop of those help? We have solved the problem on iOS by using our own implementation of the multipart POST request, with the help of NSMutableURLRequest. Still this doesn't answer why can't we use AFNetworking or place the Content-Type header on Postman, Android and AngularJS. We have a strong feeling that the issue with AFNetworking is that sends the request chunked (header transfer-encoding: chunked). We actually send the Content-Type: multipart/form-data on our custom iOS implementation, so somehow the problem is not that header at all.
On the server side, when using Postman tool while setting Content-Type header, I can verify that data comes through php://input, but does not reach, php://stdin, $_POST and $_FILES.

wish of those help I've just encountered the same issue. POSTing a file succeeds with a 200 response, but _FILES is empty. I fixed the issue by specifying the Content-Length header. E.g.:

conn.setRequestProperty("Content-Length", Integer.toString(fileInputStream.available()));

To fix this issue Finally found my mistakes!
In my code, I was submitting the form on the button click:

<button id="file_submit_btn" type="submit" form='basic_menu_dropzone' value="submit">SUBMIT</button>

<form action='<?php echo url_for("@menu_basic_menu"); ?>'method="post" enctype="multipart/form-data" class="dropzone" id="basic_menu_dropzone"></form>
<button id="file_submit_btn" type="button" form='basic_menu_dropzone' value="submit">SUBMIT</button>

jQuery(document).ready(function($) {
    Dropzone.autoDiscover = false;

    var dropzone = new Dropzone('#basic_menu_dropzone', {
        paramName: 'files',
        addRemoveLinks: true,
        uploadMultiple: true,
        autoProcessQueue: false,
        parallelUploads: 10
    });

    $('#file_submit_btn').click(function() {
        dropzone.processQueue();
    });
});

public function executeBasicMenu(sfWebRequest $request) {
    foreach($_FILES['files']['name'] as $index => $tmpName) {
      error_log($tmpName);
    }
}