Easy Upload via URL with attachment_fu
October 24th, 2008 by TrevorAllowing file uploads with attachment_fu is super easy, but I've found that users sometimes want to be able to "upload" a file directly from a URL. This saves them the steps of downloading the file, finding it on their computer, uploading it into your app, etc.
I did a bit of digging around before I came across this handy trick that makes it pretty painless to add uploading via a URL to your app. I've wrapped up the code a bit and added in a few niceties that I found necessary to avoid raising exceptions unnecessarily.
The best part is that you don't need to change anything about your controller in order to get this to work. All you need is to add the uri attribute to your model and views, and you're good to go.
# app/models/upload.rb class Upload < ActiveRecord::Base # ...normal attachment_fu code (has_attachment, etc)... # allow uploads via URL require 'open-uri' attr_reader :url def url=(uri) return nil if uri.blank? io = (open(URI.parse(uri)) rescue return nil) (class << io; self; end;).class_eval do define_method(:original_filename) { base_uri.path.split('/').last } end self.uploaded_data = io end end # app/controllers/uploads_controller.rb class UploadsController < ApplicationController # avoid raising exceptions for common errors (e.g. file not found) rescue_from Errno::ENOENT, :with => :url_upload_not_found rescue_from Errno::ETIMEDOUT, :with => :url_upload_not_found rescue_from OpenURI::HTTPError, :with => :url_upload_not_found rescue_from Timeout::Error, :with => :url_upload_not_found def new @upload = Upload.new end def create @upload = current_user.uploads.build(params[:upload]) if @upload.save redirect_to files_path else render :action => "new" end end def url_upload_not_found flash[:notice] = "Sorry, the URL you provided was not valid." redirect_to new_upload_path end end # app/views/uploads/new.html.erb <%= error_messages_for :upload %> <% form_for @upload, :html => { :multipart => true } do |f| -%> <%= f.file_field :uploaded_data # normal upload, or... %> <%= f.text_field :url # upload via url %> <%= submit_tag "Upload", :disable_with => "Upload" %> <% end %>
You can see a working example of all this in El Dorado. I was bored, so I decided to try my hand at making a screencast. Check it out - it's got an awesome soundtrack at the very least :)
If you'd like to use this for multiple models, consider refactoring it into a module that you can include elsewhere.
Hope this helps - and suggestions/improvements are always welcome!
Wow. I was just thinking about how to do this. You saved me a lot of time. Thanks.
Fantastic first try at screencasts!
This is good, I have book marked it
[...] Easy Upload via URL with attachment_fu - almost effortless [...]
[...] file uploads lately, and I wanted to be able to accept file “uploads” with a URL. We already knew how to accomplish this with attachment_fu, and getting it working in Paperclip wasn’t too [...]
This is ace. Thank you! I had a “UrlUpload” class (similar to the LocalUpload one) on one project and this tip saved my day.
Thanks!