How to upload an image to S3 using paperclip gem

Question

For the life of my I can't understand how the basic paperclip example works. There's only one line included in the controller, and that's

@user = User.create( params[:user] )

I simply don't understand how that's all that is needed to upload an image to s3. I've changed the example quite a bit because i wanted to use jquery file uploader rather than the default rails form helper, so I'm at the point where an image is being POSTed to my controller, but I can't figure out how I'm supposed to take the image from the params and assign it as an attachment. Here's what I'm seeing the logs:

Parameters: {"files"=>[#<ActionDispatch::Http::UploadedFile:0x132263b98 @tempfile=#<File:/var/folders/5d/6r3qnvmx0754lr5t13_y1vd80000gn/T/RackMultipart20120329-71039-1b1ewde-0>, @headers="Content-Disposition: form-data; name=\"files[]\"; filename=\"background.png\"\r\nContent-Type: image/png\r\n", @content_type="image/png", @original_filename="background.png">], "id"=>"385"}

My JS is very simple:

 ` $('#fileupload').fileupload({
    dataType: 'json',
    url: '/my_url',
    done: function (e, data) {
        console.log('done');
    }
});`

What would be helpful for me to know is how I can strip the file data from the POSTed parameters given above and pass it to paperclip. I'm sure that I'll have to assign the attachment attribute a value of File.open(...), but I dont know what source of my file is.

I've spent a ridiculous amount of time trying to figure this out and I can't seem to get it. I've tried uploading directly to s3, but the chain of events was terribly confusing, so I want to get this simple pass-through example completed first. Thanks so much for any help you cna give!

Answer 1

You need a few more pieces and it will help if you can show the exact code you're using.

Paperclip can post to S3 by using:

http://rubydoc.info/gems/paperclip/Paperclip/Storage/S3

When your controller creates a User model, it is sending along all the params. This is called "mass assignment" (be sure to read about attr_accessible).

When your model receives the params, it uses the Paperclip AWS processor, which uploads it.

You need the AWS gem, a valid bucket on S3, and a config file.

Try this blog post and let us know if it helps you:

http://blog.trydionel.com/2009/11/08/using-paperclip-with-amazon-s3/

UPDATE 2013-04-03: Pleases see Chloe's comment below-- you may need an additional parameter, and the blog post may be outdated.