Carrierwave how to get the file extension

Question

I'm developing a Ruby on Rails application that requires file uploading/downloading. For the upload part i used the gem carrierwave since it's very easy to use and flexible. The problem is: once i uploaded the file, i need to know a few things: i.e. if it's a pdf instead of downloading the file i show it inline,and the same goes for an image. How do i get the file extension and how can i do it to send the file to a user?? Any feedback is appreciated Thanks!!

Answer 1

Determine file extension (I suppose a name for mounted uploader is 'file'):

file = my_model.file.url
extension = my_model.file.file.extension.downcase

Then prepare mime and disposition vars:

disposition = 'attachment'
mime = MIME::Types.type_for(file).first.content_type

if %w{jpg png jpg gif bmp}.include?(extension) or extension == "pdf"
  disposition = 'inline'
end

(add other extensions if you want).

And then send the file:

send_file file, :type => mime, :disposition => disposition

Answer 2

Once you have uploaded a file, the name is stored in the database. This also includes the extension. Assuming you have a User model with an uploader mounted as asset, then you can get it as:

user.asset.file.extension

As for sending it to the user, if you call user.asset_url, it will give you the URL where the file is uploaded. The user can use that link to get the file. Or am I misunderstanding what you mean by "send the file to a user"?