Can't dump file error in rails

I am developing an application with Rails 3.0.3.

I got "Can't dump file" error at the following code.

   if @post.update_attributes params[:post]
      redirect_to post_path(@post) #<= ERROR HERE

After googling, I added 2 lines to fix that.

   if @post.update_attributes params[:post]
      params[:post][:photos_attributes] = nil
      params[:post][:attachments_attributes] = nil
      redirect_to post_path(@post)

Now the error's gone. But I don't underst开发者_高级运维and why the error occurred and how it's fixed. I use active_record for the session store and it caused the error because a file can't be stored in DB. But why does redirect_to try to store file in the session?

Thanks.

Sam

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Adding: ActiveRecord::SessionStore::Session.serializer = :json to config/application.rb solved the issue for me.

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I'm not sure what's in the photo_attributes and attachment_attributes. My guess is that they contain some sort of info on files and saving them is not working correctly.

Maybe you can post your Post model for us to see?

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I'm guessing attachment_attributes contains uploaded files.

Uploaded files are stored in params as ActionDispatch::Http::UploadedFile objects, and objects of this type are are not serialisable, hence the error.