# Help with attachment\_fu, why this error?

**URL:** <https://www.ruby-forum.com/t/help-with-attachment-fu-why-this-error/115132>\
**Category:** Rails\
**Created:** [September 20, 2007, 10:51pm UTC](https://www.ruby-forum.com/t/help-with-attachment-fu-why-this-error/115132 "2007-09-20T22:51:22Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![mix](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/919ad9/32.png) [@mix](https://www.ruby-forum.com/u/mix)\
**Post date:** [September 20, 2007, 10:51pm UTC](https://www.ruby-forum.com/t/help-with-attachment-fu-why-this-error/115132/1 "2007-09-20T22:51:22Z")

</div>

hi, i’m trying to play with attachment\_fu using imagescience, and…it  
works, partially…  
when i send the form the image is uploaded and it’s resized and the  
thumb made, and inserted in the db.  
But after this an error is occurred (every time):

TypeError (singleton can’t be dumped):  
/usr/lib/ruby/1.8/pstore.rb:349:in `dump' /usr/lib/ruby/1.8/pstore.rb:349:in `dump’  
/usr/lib/ruby/1.8/pstore.rb:330:in `transaction' /usr/lib/ruby/1.8/cgi/session/pstore.rb:81:in `update’  
/usr/lib/ruby/1.8/cgi/session/pstore.rb:88:in `close' /usr/lib/ruby/1.8/cgi/session.rb:324:in `close’  
/usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action\_controller/base.rb:1184:in  
`close_session' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:1228:in `process\_cleanup\_without\_flash’  
/usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action\_controller/flash.rb:146:in  
`process_cleanup_without_filters' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:662:in `process\_cleanup\_without\_session\_management\_support’  
/usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action\_controller/session\_management.rb:124:in  
`process_cleanup_without_components' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/components.rb:178:in `process\_cleanup’  
/usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action\_controller/base.rb:435:in  
`process_without_filters' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:624:in `process\_without\_session\_management\_support’  
/usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action\_controller/session\_management.rb:114:in  
`process' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:330:in `process’  
/usr/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/dispatcher.rb:41:in  
`dispatch' /usr/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/webrick_server.rb:113:in `handle\_dispatch’  
/usr/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/webrick\_server.rb:79:in  
`service' /usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service’  
/usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run' /usr/lib/ruby/1.8/webrick/server.rb:173:in `start\_thread’  
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start' /usr/lib/ruby/1.8/webrick/server.rb:162:in `start\_thread’  
/usr/lib/ruby/1.8/webrick/server.rb:95:in `start' /usr/lib/ruby/1.8/webrick/server.rb:92:in `each’  
/usr/lib/ruby/1.8/webrick/server.rb:92:in `start' /usr/lib/ruby/1.8/webrick/server.rb:23:in `start’  
/usr/lib/ruby/1.8/webrick/server.rb:82:in `start' /usr/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/webrick_server.rb:63:in `dispatch’  
/usr/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/commands/servers/webrick.rb:59  
/usr/lib/ruby/site\_ruby/1.8/rubygems/custom\_require.rb:27:in  
`gem_original_require' /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `require’  
/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active\_support/dependencies.rb:495:in  
`require' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:342:in `new\_constants\_in’  
/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active\_support/dependencies.rb:495:in  
`require' /usr/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/commands/server.rb:39 /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem\_original\_require’  
/usr/lib/ruby/site\_ruby/1.8/rubygems/custom\_require.rb:27:in  
`require' ./script/server:3 -e:4:in `load’  
-e:4

this is the controller:

def aaaaa  
@image = Image.new  
end

def bbbbb  
@image = Image.new(params[:image])  
if @image.save  
flash[:notice] = ‘image was successfully created.’  
redirect\_to :action =\> :aaaaa  
else  
render :action =\> :new  
end  
end

model:

has\_attachment :content\_type =\> :image,  
:storage =\> :file\_system,  
:max\_size =\> 500.kilobytes,  
:resize\_to =\> ‘320x200\>’,  
:thumbnails =\> { :thumb =\> ‘100x100\>’ }

validates\_as\_attachment

view:

\<%= error\_messages\_for :image %\>

\<% form\_for(:image, :url =\> {:action =\> :bbbbb}, :html =\> { :multipart  
=\> true }) do |f| -%\>

Upload An image: \<%= f.file\_field :uploaded\_data %\>

\<%= submit\_tag 'Create' %\>

\<% end -%\>

table:

```
create_table :images do |t|
  t.column :parent_id, :integer
  t.column :content_type, :string
  t.column :filename, :string
  t.column :thumbnail, :string
  t.column :size, :integer
  t.column :width, :integer
  t.column :height, :integer
end

```

it’s about 3 hours i’m trying to fix this, but without any result…and  
the code is the same i found here:  
[http://clarkware.com/cgi/blosxom/2007/02/24](http://clarkware.com/cgi/blosxom/2007/02/24)  
can anyone help me? please ☹  
thanks