Amazon S3 CORS POST fails with JQuery-file-upload

Question

I'm trying to upload files to S3 through an HTML uploader, I tried to follow this tutorial :

http://pjambet.github.com/blog/direct-upload-to-s3/

I'm able to post files through regular html form. But if i post the same form with JQuery-file-upload plugin i get a 403 from Amazon.

Here is my form :

<form accept-charset="UTF-8" action="https://youboox_dev.s3.amazonaws.com" enctype="multipart/form-data" class='direct-upload' method="POST">
 <input type="hidden" name="key" value="test-file-name">
 <input type="hidden" name="AWSAccessKeyId" value="AKIZ[...]YSCA">
 <input type="hidden" name="acl" value="private">
 <input type="hidden" name="success_action_status" value="201">
 <input type="hidden" name="policy" value="<%= Facades::AmazonFacade.policy %>">
 <input type="hidden" name="signature" value="<%= Facades::AmazonFacade.signature %>">

 <input type="file" name="file">

 <input type="submit" value="Load this file">

And here is my jquery-uploader :

$('.direct-upload').fileupload({
      url: $(this).attr('action'),
      type: 'POST',
      autoUpload: true,
      dataType: 'xml',
      add: function (event, data) {
        jqXHR = data.submit();
      }

I get this answer from amazon :

OPTIONS https://youboox_dev.s3.amazonaws.com/ 200 (OK)
POST https://youboox_dev.s3.amazonaws.com/ 403 (Forbidden)

========================================================

I'm pretty sure my policy and signature are correct since when i just submit this form through the submit button, i get a ok response from amazon and 'im able to download the file i just uploaded :

<PostResponse>
  <Location>https://youboox_dev.s3.amazonaws.com/tottotoCVBNBV</Location>
  <Bucket>youboox_dev</Bucket>
  <Key>test-file-name</Key>
  <ETag>"d41d8cd98f00b204e9800998ecf8427e"</ETag>
</PostResponse>

Answer 1

I was having similar option (I never tested a direct form POST). What fixed it for me was adding a bucket policy:

{
"Version": "2008-10-17",
"Id": "Policy1347277692345",
"Statement": [
    {
        "Sid": "my-user",
        "Effect": "Allow",
        "Principal": {
            "AWS": "arn:aws:iam::123456789:user/my-user"
        },
        "Action": [
            "s3:AbortMultipartUpload",
            "s3:GetObjectAcl",
            "s3:GetObjectVersion",
            "s3:DeleteObject",
            "s3:DeleteObjectVersion",
            "s3:GetObject",
            "s3:PutObjectAcl",
            "s3:PutObjectVersionAcl",
            "s3:ListMultipartUploadParts",
            "s3:PutObject",
            "s3:GetObjectVersionAcl"
        ],
        "Resource": "arn:aws:s3:::my-bucket/*"
    },
    {
        "Sid": "world-readable",
        "Effect": "Allow",
        "Principal": {
            "AWS": "*"
        },
        "Action": "s3:GetObject",
        "Resource": "arn:aws:s3:::my-bucket/*"
    }
]
}

(I admit to just copying this blindly from another bucket someone else had set up so I don't know which parts of this are actaully needed.)