A workaround to pre-populate file_field? - ruby-on-rails

Question

I don't think you can literally pre-populate the file_field so I've been struggling with a workaround for the same end goal, which is to take an image already uploaded to the application via User A and then for User B to be able to save that same image as his own too, similar to pinterest.
This is what I've tried:
index
<%= link_to new_inspiration_path(inspiration_image: inspiration.image) %>
controller
def new
#inspiration = current_user.inspirations.build
#inspiration.image = URI.parse(params[:inspiration_image])
end
server
Started GET "/inspirations/new?inspiration_image=%2Fsystem%2Finspirations%2Fimages%2F000%2F000%2F069%2Foriginal%2Frule_1.jpg%3F1478260961" for 127.0.0.1 at 2016-11-04 08:10:41 -0400
Processing by InspirationsController#new as */*
Parameters: {"inspiration_image"=>"/system/inspirations/images/000/000/069/original/rule_1.jpg?1478260961"} # For example, this is the image url I'm trying to duplicate for User B
User Load (0.3ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT 1 [["id", 129]]
Inspiration Load (0.4ms) SELECT "inspirations".* FROM "inspirations" WHERE "inspirations"."id" IS NULL LIMIT 1
Completed 400 Bad Request in 6ms
_form
<%= simple_form_for(#inspiration, html: { data: { modal: true } }) do |f| %>
<%= image_tag #inspiration.image.url if #inspiration.image.present? %> # I get error: ActionController::ParameterMissing (param is missing or the value is empty: inspiration):
<%= f.file_field :image %>
<% end %>
model
class Inspiration < ActiveRecord::Base
has_attached_file :image, :styles => { :medium => "300x300>", :small => "150x150>" }
validates_attachment_content_type :image, :content_type => ["image/jpg", "image/jpeg", "image/png", "image/gif"]
belongs_to :user
def image_remote_url=(url_value)
self.image = URI.parse(url_value).to_s unless url_value.blank?
super
end
end

Answer 1

Change #inspiration.image assignment to #inspiration.image = URI.parse(params[:inspiration_image])
More info can be found here: https://github.com/thoughtbot/paperclip/wiki/Attachment-downloaded-from-a-URL
EDIT:
Change model according to the info in the link:
attr_reader :image_remote_url
#image_remote_url = url_value
Remove super call
Change assignment to #inspiration.image_remote_url = params[:inspiration_image]