Using Uploadify to POST Directly to Amazon S3

Can anyone tell me how to use Uploadify to upload directly to Amazon S3?

My code is as follows:

$('#fileInput').uploadify({
  'fileDataName' : 'file',
  'uploader'  : 'uploadify.swf',
  'script'    : 'http://BUCKET-NAME-GOES-HERE.s3.amazonaws.com/',
  'cancelImg' : 'cancel.png',
  'method'    : 'post',
  'auto'      : true,
  'onError': function (a, b, c, d) {
    alert('error '+d.type+": "+d.info + ' name: ' + c.name + ' size: ' + c.size);
  },
  'scriptData' : {
    'AWSAccessKeyId': "KEY-GOES-HERE",
    'key': "${filename}",
    'acl': "public-read",
    'policy': "POLICY-STRING-GOES-HERE",
    'signature': "SIGNATURE-GOES-HERE",
    'success_action_status': '200'
  }
});

My (unencoded) policy string looks like this:

{
  "expiration": "2100-12-01T12:00:00.000Z",
  "conditions": [
    {"acl": "public-read"},
    {"bucket": "BUCKET-NAME-GOES-HERE"},
    {"success_action_status" : 200},
    ["starts-with", "$filename", ""],
    ["starts-with", "$folder", ""],
    ["starts-with", "$key", ""],
    ["content-length-range", 1, 209715200]
  ]
}

Using the above code actually allows me to select a file, which it then appears to upload (somewhere), but nothing shows up in my S3 bucket and no errors are returned to the JS console.

Using a regular HTML form to post a file to the S3 bucket works fine.

Solution

From this thread the uploadify forum:

<html>
<head>
<script type="text/javascript" src="jquery-1.3.2.min.js"></script>
<script type="text/javascript" src="swfobject.js"></script>
<script type="text/javascript" src="jquery.uploadify.v2.1.0.js"></script>
<link rel="stylesheet" href="uploadify.css" type="text/css" media="screen" />
</head>

<body>
<form>
<input id="fileInput" name="fileInput" type="file" />
</form>
<script type="text/javascript">// <![CDATA[
   $(document).ready(function() {
      $('#fileInput').uploadify({
         'fileDataName' : 'file',
          'uploader'  : 'uploadify.swf',
          'script'    : 'http://UPLOADBUCKET/',
          'cancelImg' : 'cancel.png',
          'auto'      : true,
          'onError' : function(errorObj, q, f, err) { console.log(err); },

          'scriptData' : {
              AWSAccessKeyId: "ACCESS_KEY",
             key: "foo/${filename}",
             acl: "public-read",
             policy: "POLICY STRING"
             signature: "SIGNATURE,
                success_action_status: '200'
             }

          });
    });
// ]]></script>
</body>

</html>

The base for the policy string is as follows:

{ "expiration": "2100-12-01T12:00:00.000Z",
"conditions": [
  {"acl": "public-read" },
  {"bucket": "UPLOADBUCKET" },
  {"success_action_status" : '200'},
    ["starts-with", "$filename", "" ],
    ["starts-with", "$folder", "" ],
    ["starts-with", "$key", "foo"],
    ["content-length-range", 1, 209715200]
  ]
}