问题
I am new to Rails and i'm working on my first rails application that uses paperclip for attachments and i'm validating the presence of attachment using validates_attachment :avatar, presence: true which is working perfectly well on create action, but when a user is editing his account settings and doesn't upload a new avatar, there is an error for not having avatar uploaded but i want to skip that validation on edit and only validate on edit if user uploads a new one to replace existing one.
i also have
validates_format_of :avatar, :with => %r{\.(jpg|jpeg|gif|png)$}i,:unless => Proc.new {|m| m[:avatar].nil?}, :message => "Please upload files with the following extensions only
to check format only if present but doesn't seem to be working either your help would be very much appreciated. thanks
回答1:
Use on option.
validates_format_of :avatar ... , :on => :create
http://guides.rubyonrails.org/v2.3.11/activerecord_validations_callbacks.html#on
来源：https://stackoverflow.com/questions/12686443/rails-3-2-skip-paperclip-attachment-presence-validation-on-edit-action