Question

这是我的Image模型，我在其中实现了验证附件尺寸的方法：

class Image < ActiveRecord::Base
  attr_accessible :file

  belongs_to :imageable, polymorphic: true

  has_attached_file :file,
                     styles: { thumb: '220x175#', thumb_big: '460x311#' }

  validates_attachment :file,
                        presence: true,
                        size: { in: 0..600.kilobytes },
                        content_type: { content_type: 'image/jpeg' }

  validate :file_dimensions

  private

  def file_dimensions(width = 680, height = 540)
    dimensions = Paperclip::Geometry.from_file(file.queued_for_write[:original].path)
    unless dimensions.width == width && dimensions.height == height
      errors.add :file, "Width must be #{width}px and height must be #{height}px"
    end
  end
end

这样可以正常工作，但它不可重复使用，因为该方法采用宽度和宽度的固定值。高度。我想将其转换为自定义验证器，因此我也可以在其他模型中使用它。我已经阅读了有关此内容的指南，我知道在app / models / dimensions_validator.rb中它会是这样的：

class DimensionsValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    dimensions = Paperclip::Geometry.from_file(record.queued_for_write[:original].path)

    unless dimensions.width == 680 && dimensions.height == 540
      record.errors[attribute] << "Width must be #{width}px and height must be #{height}px"
    end
  end
end

但我知道我遗漏了一些因为这段代码不起作用。问题是我想在我的模型中调用这样的验证：

validates :attachment, dimensions: { width: 300, height: 200}。

有关如何实施此验证器的任何想法吗？

Answer 1

将它放在app / validators / dimensions_validator.rb中：

class DimensionsValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    # I'm not sure about this:
    dimensions = Paperclip::Geometry.from_file(value.queued_for_write[:original].path)
    # But this is what you need to know:
    width = options[:width]
    height = options[:height] 

    record.errors[attribute] << "Width must be #{width}px" unless dimensions.width == width
    record.errors[attribute] << "Height must be #{height}px" unless dimensions.height == height
  end
end

然后，在模型中：

validates :file, :dimensions => { :width => 300, :height => 300 }

Answer 2

有一个名为paperclip-dimension-validator的宝石。

回形针图像尺寸自定义验证器

2 个答案: