Smarter paperclip validations

Question

I'm using paperclip in a rails app and have the following three validations in my model

validates_attachment_presence :photo                    
validates_attachment_size :photo, :less_than=>1.megabyte
validates_attachment_content_type :photo, :content_type=>['image/jpeg', 'image/png', 'image/gif'] 

If the user forgets to add an attachment, all three validations fail and thus, the user is presented with the following three errors:

# Photo file name must be set.
# Photo file size file size must be between 0 and 1048576 bytes.
# Photo content type is not included in the list

I think it would be best to just show the first error in this instance since the other two errors are purely consequential... I would prefer the user to only ever see the second two errors if an attachment has been added but doesn't meet the validation criteria.

I'm certain there is no pre-baked validation that does this sort of thing and from reading the code in vendor/plugins/paperclip/lib/paperclip.rb I see that the validates_attachment_size method supports the :unless parameter as shown:

def validates_attachment_presence name, options = {}
  message = options[:message] || "must be set."
  validates_presence_of :"#{name}_file_name", 
                        :message => message,
                        :if      => options[:if],
                        :unless  => options[:unless]
end

So, I was thinking that I could do something like the following:

validates_attachment_size :photo, :less_than=>1.megabyte, :unless=> :photo.blank

But that breaks the app. Anyone have any experience of doing this sort of thing? Would be a nice contribution to the paperclip source code.

EDIT:

I've tried using this:

validates_attachment_size :photo, :less_than=>1.megabyte, 
     :unless=> Proc.new { |image| image[:photo].nil? }

It doesn't quite work though as I've just managed to upload a 5mb mp3 with this validation in place. But it's promising as the error message doesn't appear when the user has not attached a photo.

Sherrer

Which version of paperclip are you using? I've got 2.3.1.1 and what you are describing happens automatically for me. If no file is attached, it only returns that error. If I attach a file, but the size and content type validations fail, it then shows those errors. – Phrixus

strange because I'm on 2.3.1.1 of the plugin too... i'm going to go with the suggestion below about creating my own custom error messages anyway because I really don't like the way they tell you the attacment needs to be between 0 and X bytes.... – Sherrer

I'm using 2.3.2 with same problem – Clayborn

Answer 1

validates_attachment_size :photo, :less_than => 1.megabyte, 
  :unless => Proc.new { |imports| imports.photo_file_name.blank? }

Eachern

Better than that: :if => Proc.new { |imports| !imports.photo.file? } – Franglais

I don't know what version this answer was given on but it isn't working on my local system (running Paperclip 2.3.11 on Rails 3.1.3). – Crimpy

Answer 2

I think you can do it other way. Don't mess with validations. You probably have something like this in your form:

<%= f.error_messages %>

You can remove it and write your own helper to display error messages. Errors are stored in hash:

@photo.errors

Or if you want to get to them through form builder:

f.object.errors

Sicular