title: $_FILES is always empty
body: <p>I am uploading a PDF to my server through my web-service, but $_FILES always seems to be empty regardless of what I do.</p>
  
  <p>The program that will be uploading the PDF is an OSX program (via AFNetworking). I have ruled this out as a possibility of causing the issue as when I attempt to upload the file through 'CocoaRestClient' (similar to POSTMAN on chrome) I get nothing. In CocoaRestClient I am setting my ContentType to 'multipart/form-data'.</p>
  
  <p>The PDF I am attempting to upload is 478kb so I do not think that size is the issue.</p>
  
  <p>My PHP code is below. At the moment I am just trying to see if anything is in the $_FILES array at all.</p>
  
  <pre><code>&lt;?php
  
  header('Content-type: multipart/form-data');
  
  $fileName = $_FILES['PDF']['name'];
  $tmpName  = $_FILES['PDF']['tmp_name'];
  $fileSize = $_FILES['PDF']['size'];
  $fileType = $_FILES['PDF']['type'];
  
  $response = array("filename" =&gt; $fileName,
                    "tmpName" =&gt; $tmpName,
                    "fileSize" =&gt; $fileSize,
                    "filetype" =&gt; $fileType,
                    "FILES" =&gt; $_FILES);
  
  echo json_encode($response);
  
  ?&gt;
  </code></pre>
  
  <p>This is the response I get from the JSON</p>
  
  <pre><code>{"filename":null,
   "tmpName":null,
   "fileSize":null,
   "filetype":null,
   "FILES":[]}
  </code></pre>
  
  <p>This is my objective-C code.</p>
  
  <pre><code>                [manager POST:pdfURL
                     parameters:nil
      constructingBodyWithBlock:^(id &lt;AFMultipartFormData&gt; formData) {
          [formData appendPartWithFileData:pdf name:@"PDF" fileName:filename mimeType:@"multipart/form-data"];
      }
  
                        success:^(NSURLSessionDataTask *operation, id responseObject) {
                          [self checkForErrorInResponse:responseObject];
  
                          [delegate pdfUploadedSuccessfullyWithResponse:responseObject];
                      }
  
                        failure:^(NSURLSessionDataTask *operation, NSError *error) {
                            [delegate pdfFailedToUploadWithError:error];
                        }];
  </code></pre>
  
  <p>After using POSTMAN to determine that my php is working correctly, I can conclude that my objective-C code is causing the bug. What is strange however, is that even though my php code returns null's, Charles is telling me that the PDF IS being uploaded!</p>