title: Uploadify uploading arbitrary file to s3 with correct Content-type
body: <p>I need to be able to upload any file type, for example, both pdf and jpeg. S3 requires the content-type be set at the time of upload, or the file will not be served correctly</p>
  
  <p>Is it possible to dynamically assign the content-type in the onSelect callback or elsewhere?</p>
  
  <p>The content-type is set in the postData parameter to uploadify (scriptData in older uploadify versions). Right now I have no way to set this until a file is selected. After the file is selected I could determine (mostly accurately) the content-type from the file extension. Now all files are served as application/octet-stream, which makes them pretty useless.</p>