I have asked this question before, but it was deleted due too little information. I'll try to be more concrete this time.

I have an Objective-C mac application, which should allow users to upload files to S3-storage. The s3 storage is mine, the users don't have an Amazon account. Until now, the files were uploaded directly to the amazon servers. After thinking some more about it, it wasn't really a great concept, regarding security and flexibility. I want to add a server in between. The user should authenticate with my server, the server would open a session if the authentication was successful, and the file-sharing could begin.

Now my question. I want to upload the files to S3. One option would be to make a POST-request and wait until the server would receive the file. Problems here are, that there would be a delay, when the file is being uploaded from my server to the S3 servers, and it would double the uploading time.

Best would be, if I could validate the request, and then redirecting it, so the client uploads it directly to the s3-storage. Not sure if this is possible somehow.

Uploading directly to S3 doesn't seem to be very smart. After looking into other apps like Droplr and Dropmark, it looks like they don't do this. Btw. I did this using Little Snitch.

They have their api on their own web-server, and that's it.

Could someone clear things up for me?

EDIT How should I transmit my files to S3? Is there a way to "forward" it, or do I have to upload it to my server and then upload it from there to S3? Like I said, other apps can do this efficiently and without the need of communicating with S3 directly.