Rails%203%20In%20Action

242 CHAPTER 9 File uploading
After multiple-file uploading, you learned how to restrict which files are served
through your application by serving them through a controller. By using a controller,
you can use CanCan’s can? helper to determine if the currently signed-in user has
access to the requested asset’s project. If so, then you give the user the requested asset
using the send_file controller method. If not, you deny all knowledge of the asset
ever having existed.
Finally, you used a JavaScript library called jQuery, in combination with a simpler
way of writing JavaScript called CoffeeScript, to provide users with an Add Another
File link. jQuery does more than simple asynchronous requests, though, and if you’re
interested, the documentation 14 is definitely worth exploring.
In the next chapter, we look at giving tickets a concept of state, which enables users
to see which tickets need to be worked on and which are closed. Tickets will also have
a default state so they can be easily identified when they’re created.
14 http://jquery.com.