Rails - Paperclip Validating Attachment Size When It Shouldn't Be

Paperclip validating when no attachment

Try the following code.

validate :image_present

def image_present
  if image.present? && image_file_size < 2.megabytes
    errors.add(:file_size, "file size must be between 0 and 2 megabytes.")
  end
end

Here, the validation will work if there is image present in the model and will skip the validation if there is no image.

Validate attachment content type Paperclip in Rails 2 application

You are getting image must be jpg or png when trying to save without image because if the image is not present which implies that the content type is also missing i.e. they are not jpg or png.

To accomplish your task, you can add a custom validator where first you will check if the image is present and if yes, only then you will check the :content_type of the image.

Add these in your Product Model:

  validate :master_image_type_present

  def master_image_type_present
    if master_image.present? && !(['image/png', 'image/jpg', 'image/jpeg'].include? master_image_content_type)
      errors.add(:content_type, "invalid content type")
    end
  end

And, your validation will work as expected.

Paperclip and failed validation - avoid reupload

I use the two-step solution with a separate model. Although it's possible to code and hack your way around the default behaviour, you could also validate on the client-side with JS.

Paperclip and Postgres

Alison R. has posted a comment to the solution, but let me write a complete solution.

Try this:

validates_attachment_size :avatar, :less_than => 1.megabytes,
  :unless => Proc.new {|model| model.avatar }

Paperclip: specify attachment fields in post_process callbacks

According to Paperclip documentation, you should be able to use before_bar_post_process callback and if you return false the post processing for bar will be halted:

class Attachment < ActiveRecord::Base

    has_attached_file :foo
    has_attached_file :bar

    before_bar_post_process check_bar_condition

    def check_bar_condition
        ...
        return false if #some_condition_fails
        ...
    end
end

Rails Paperclip how to delete attachment?

First off, when you create a check_box in a form_for (which it looks like you are), then the form should by default send :image_delete as "1" if checked and "0" if unchecked. The method declaration looks like this:

def check_box(method, options = {}, checked_value = "1", unchecked_value = "0")

Which shows that you can assign other values if you want to, but that is of course optional.

Secondly, the call to manually delete an attachment without deleting the model instance to which it is attached to is:

@page.image.destroy #Will remove the attachment and save the model
@page.image.clear #Will queue the attachment to be deleted

And to accomplish your way of deleting the images through a checkbox, perhaps add something like this to your Page model:

class Page < ActiveRecord::Base
  has_attached_file :image

  before_save :destroy_image?

  def image_delete
    @image_delete ||= "0"
  end

  def image_delete=(value)
    @image_delete = value
  end

private
  def destroy_image?
    self.image.clear if @image_delete == "1"
  end
end

This way, when you create your form and add the :image_delete checkbox, it will load the default value "0" from the User instance. And if that field is checked then the controller will update the image_delete to "1" and when the User is saved, it will check if the image is to be deleted.

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