Here\'s a story:
If you want to host files yourself, you can perform authentication at the controller level as has been suggested. One of my applications has an AssetController that handles serving of files from the 'private' directory, for example.
One thing I wanted to add is that you should review this guide for setting up X-Sendfile, which will let your application tell the web server to handle actually sending the files. You'll see much better performance with this approach.
You may make your rails server output the contents of image files. This is done via a controller action (most of actions print HTML, but this one will print JPG, for example).
Then you may use your authorization system to restrict access on controller level!
class ImagesController
#Default show Image method streams the file contents.
#File doesn't have to be in public/ dir
def show
send_file @image.filename, :type => @image.content_type,
:disposition => 'inline'
end
# Use your favorite authorization system to restrict access
filter_access_to :show, :require => :view, :attribute_check => :true
end
In HTML code you may use:
<img src="/images/show/5" />
I would have Paperclip use S3 on the back-end, set uploaded files to private, and then use "Query String Request Authentication Alternative" to generate the URLs for my image tags.
http://docs.amazonwebservices.com/AmazonS3/2006-03-01/index.html?RESTAuthentication.html
Here's how I did this in a similar application.
Mine looks like this:
def s3_url(style = :original, time_limit = 30.minutes)
self.attachment.s3.interface.get_link(attachment.s3_bucket.to_s, attachment.path(style), time_limit)
end