I'm using plupload 1.4.2 to upload files directly to an Amazon S3 bucket. The question is, how can I upload them to a subfolder directly? What parameters should I configure in the policy or plupload object config?
Amazon S3 there is no concept of folder or subfolder. Only objects. And an object has a key.
If you wanna upload a file to a folder or subfolder, simply put the object key like this:
$key = "folder/subfolder/filename.extension";
And Amazon S3 will create the (imaginary) folder(s) and subfolder(s).