dropbox_controller.rb

require 'dropbox_sdk'

# This is an example of a Rails 3 controller that authorizes an application
# and then uploads a file to the user's Dropbox.

# You must set these
APP_KEY = ""
APP_SECRET = ""
ACCESS_TYPE = :app_folder #The two valid values here are :app_folder and :dropbox
                          #The default is :app_folder, but your application might be
                          #set to have full :dropbox access.  Check your app at
                          #https://www.dropbox.com/developers/apps


# Examples routes for config/routes.rb  (Rails 3)
#match 'db/authorize', :controller => 'db', :action => 'authorize'
#match 'db/upload', :controller => 'db', :action => 'upload'

class DbController < ApplicationController
    def authorize
        if not params[:oauth_token] then
            dbsession = DropboxSession.new(APP_KEY, APP_SECRET)

            session[:dropbox_session] = dbsession.serialize #serialize and save this DropboxSession

            #pass to get_authorize_url a callback url that will return the user here
            redirect_to dbsession.get_authorize_url url_for(:action => 'authorize')
        else
            # the user has returned from Dropbox
            dbsession = DropboxSession.deserialize(session[:dropbox_session])
            dbsession.get_access_token  #we've been authorized, so now request an access_token
            session[:dropbox_session] = dbsession.serialize

            redirect_to :action => 'upload'
        end
    end

    def upload
        # Check if user has no dropbox session...re-direct them to authorize
        return redirect_to(:action => 'authorize') unless session[:dropbox_session]

        dbsession = DropboxSession.deserialize(session[:dropbox_session])
        client = DropboxClient.new(dbsession, ACCESS_TYPE) #raise an exception if session not authorized
        info = client.account_info # look up account information

        if request.method != "POST"
            # show a file upload page
            render :inline =>
                "#{info['email']} <br/><%= form_tag({:action => :upload}, :multipart => true) do %><%= file_field_tag 'file' %><%= submit_tag %><% end %>"
            return
        else
            # upload the posted file to dropbox keeping the same name
            resp = client.put_file(params[:file].original_filename, params[:file].read)
            render :text => "Upload successful! File now at #{resp['path']}"
        end
    end
end