The scenario is a normal model that contains a paperclip attachment along with some other columns that have various validations. When a form to to create an object cannot be saved due to a validation error unrelated to the attachment, columns like strings are preserved and remain prefilled for the user, but a file selected for uploading is completely lost and must be reselected by the user.
Is there a standard approach to preserving the attachment in the case of a model validation error? This seems like a very common use case.
It seems inelegant to hack up a solution where the file is saved without an owner and then reconnected to the object after it's successfully saved so I'm hoping to avoid this.
Switch to using CarrierWave. I know this was in a comment, but I just spent all day making the transition so my answer may be helpful still.
First you can follow a great railscast about setting up carrier wave: http://railscasts.com/episodes/253-carrierwave-file-uploads
To get it to preserve the image between posts, you need to add a hidden field with the suffix 'cache':
<%= form_for @user, :html => {:multipart => true} do |f| %>
<p>
<label>My Avatar</label>
<%= f.file_field :avatar %>
<%= f.hidden_field :avatar_cache %>
</p>
<% end %>
For Heroku
And if you're deploying to Heroku like I am, you need to make some changes to get it to work, since the caching works by temporarily saving uploads in a directory called public/uploads. Since the filesystem is readonly in Heroku, you need to have it use the tmp folder instead, and have rack serve static files from there.
Tell carrierwave to use the tmp folder for caching.
In your config/initializers/carrierwave.rb (feel free to create if not there), add:
CarrierWave.configure do |config|
config.root = Rails.root.join('tmp')
config.cache_dir = 'carrierwave'
end
Configure rack to serve static files in from the tmp/carrierwave folder
In your config.ru file, add:
use Rack::Static, :urls => ['/carrierwave'], :root => 'tmp'
For an example of a fully functional barebones rails/carrierwave/s3/heroku app, check out:
https://github.com/trevorturk/carrierwave-heroku (no affiliation, just was useful).
Hope this helps!
I had to fix this on a recent project using PaperClip. I've tried calling cache_images() using after_validation and before_save in the model but it fails on create for some reason that I can't determine so I just call it from the controller instead.
model:
class Shop < ActiveRecord::Base
attr_accessor :logo_cache
has_attached_file :logo
def cache_images
if logo.staged?
if invalid?
FileUtils.cp(logo.queued_for_write[:original].path, logo.path(:original))
@logo_cache = encrypt(logo.path(:original))
end
else
if @logo_cache.present?
File.open(decrypt(@logo_cache)) {|f| assign_attributes(logo: f)}
end
end
end
private
def decrypt(data)
return '' unless data.present?
cipher = build_cipher(:decrypt, 'mypassword')
cipher.update(Base64.urlsafe_decode64(data).unpack('m')[0]) + cipher.final
end
def encrypt(data)
return '' unless data.present?
cipher = build_cipher(:encrypt, 'mypassword')
Base64.urlsafe_encode64([cipher.update(data) + cipher.final].pack('m'))
end
def build_cipher(type, password)
cipher = OpenSSL::Cipher::Cipher.new('DES-EDE3-CBC').send(type)
cipher.pkcs5_keyivgen(password)
cipher
end
end
controller:
def create
@shop = Shop.new(shop_params)
@shop.user = current_user
@shop.cache_images
if @shop.save
redirect_to account_path, notice: 'Shop created!'
else
render :new
end
end
def update
@shop = current_user.shop
@shop.assign_attributes(shop_params)
@shop.cache_images
if @shop.save
redirect_to account_path, notice: 'Shop updated.'
else
render :edit
end
end
view:
= f.file_field :logo
= f.hidden_field :logo_cache
- if @shop.logo.file?
%img{src: @shop.logo.url, alt: ''}
Following the idea of @galatians , i got this solution (and worked beautfully )
Created a repo to that example: * https://github.com/mariohmol/paperclip-keeponvalidation
- The first thing to do is put some methods in your base active record, so every model that uses attach you can make it work
In config/initializers/active_record.rb
module ActiveRecord
class Base
def decrypt(data)
return '' unless data.present?
cipher = build_cipher(:decrypt, 'mypassword')
cipher.update(Base64.urlsafe_decode64(data).unpack('m')[0]) + cipher.final
end
def encrypt(data)
return '' unless data.present?
cipher = build_cipher(:encrypt, 'mypassword')
Base64.urlsafe_encode64([cipher.update(data) + cipher.final].pack('m'))
end
def build_cipher(type, password)
cipher = OpenSSL::Cipher::Cipher.new('DES-EDE3-CBC').send(type)
cipher.pkcs5_keyivgen(password)
cipher
end
#ex: @avatar_cache = cache_files(avatar,@avatar_cache)
def cache_files(avatar,avatar_cache)
if avatar.queued_for_write[:original]
FileUtils.cp(avatar.queued_for_write[:original].path, avatar.path(:original))
avatar_cache = encrypt(avatar.path(:original))
elsif avatar_cache.present?
File.open(decrypt(avatar_cache)) {|f| assign_attributes(avatar: f)}
end
return avatar_cache
end
end
end
- After that , include in your model and attached field, the code above
In exemple, i included that into /models/users.rb
has_attached_file :avatar, PaperclipUtils.config
attr_accessor :avatar_cache
def cache_images
@avatar_cache=cache_files(avatar,@avatar_cache)
end
In your controller, add this to get from cache the image (just before the point where you save the model)
@user.avatar_cache = params[:user][:avatar_cache]
@user.cache_images
@user.save
And finally include this in your view, to record the location of the current temp image
f.hidden_field :avatar_cache
- If you want to show in view the actual file, include it:
<% if @user.avatar.exists? %> <label class="field">Actual Image </label> <div class="field file-field"> <%= image_tag @user.avatar.url %> </div> <% end %>
As of Sept 2013, paperclip has no intention of "fixing" the losing of attached files after validation. "The problem is (IMHO) more easily and more correctly avoided than solved"
https://github.com/thoughtbot/paperclip/issues/72#issuecomment-24072728
I'm considering the CarrierWave solution proposed in John Gibb's earlier solution
Also check out refile (newer option)
Features:
- Configurable backends, file system, S3, etc...
- Convenient integration with ORMs
- On the fly manipulation of images and other files
- Streaming IO for fast and memory friendly uploads
- Works across form redisplays, i.e. when validations fail, even on S3
- Effortless direct uploads, even to S3
- Support for multiple file uploads
If the image isn't required why not split the form into two stages, the first one creates the object, the second page lets you add optional information (like a photo).
Alternatively you could validate the form as the user enters the information so that you don't have to submit the form to find out your data is invalid.
save your picture first than try the rest
lets say you have a user with a paperclip avatar:
def update
@user = current_user
unless params[:user][:avatar].nil?
@user.update_attributes(avatar: params[:user][:avatar])
params[:user].delete :avatar
end
if @user.update_attributes(params[:user])
redirect_to edit_profile_path, notice: 'User was successfully updated.'
else
render action: "edit"
end
end
In view file just put if condition that should accept only the record which had valid id. In my scenario this is the code snippet
<p>Uploaded files:</p>
<ul>
<% @user.org.crew.w9_files.each do |file| %>
<% if file.id.present? %>
<li> <%= rails code to display value %> </li>
<% end %>
<% end %>
</ul>
来源：https://stackoverflow.com/questions/5198602/not-losing-paperclip-attachment-when-model-cannot-be-saved-due-to-validation-err