FineUploader: Harvest original last modified date when uploading to Amazon S3

Question

I would like to send the last modified date of the uploaded file to the server. I have the javascroipt snippet to get that using FileApi ($(this).fineUploaderS3('getFile', id).lastModifiedDate). I would like to send this information when the uploadSuccess's endPoint is called, but I cannot find the callback which is right for me at Events | Fine Uploader documentation, and I cannot find the way I could inject the data.

These are submitted as POST parameters to my server when the upload finished to S3: key, uuid, name, bucket. I would like to inject the lastModified date here somehow.

Option 2:

Asking the Amazon S3 service about last modification date does not help directly, because the uploaded file has the current date, not the file's original date. It would be great if we could inject the information into the FineUploader->S3 communication in a way that S3 would use it for setting it's own last modified date for the uploaded file.

Other perspective I considered:

If I use onSubmit and setParams then I the Amazon S3 server will take it as 'x-amz-meta-lastModified'. The problem is that when I upload larger files (which is uploaded in chunks with an other dance) then I get signing error. ...<Code>SignatureDoesNotMatch</Code><Message>The request signature we calculated does not match the signature you provided. Check your key and signing method.</Message>....

EDIT

The Other perspective I considered works. The bottleneck was the name of the custom metadata chih I used at setParams. It cannot contain capital letters, otherwise the signing fails. I did not find any reference documentation for it. For one I checked Object Key and Metadata - Amazon Simple Storage Service. If someone could find me a reference I would include that here.

The original question (when and how to send last modified date to the server component) remains.

(Server is PHP.)

EDIT2

The Option 2 will not work, as far my research went the "Last Modified" entry cannot be manually altered at Amazon S3.

Answer 1

If the S3 API does not return the expected last modified date, you can check the value of the lastModifiedDate on the File object associated with the upload (provided the browser supports the file API) and send that value as a parameter to the upload success endpoint. See the documentation for the setUploadSuccessParams API method for more details.