如何创建自定义回形针处理器以检索图像尺寸 Rails 4

Question

我想在创建附加文件之前检索图像上传尺寸。我通过模型通过 Extracting Image dimensions 得到了这个。但我想通过自定义处理器发送。我试过的是： Player.rb

class Player < ActiveRecord::Base
  has_attached_file :avatar, processors: [:custom], :style => {:original => {}}
....
end

/lib/paperclip_processors/custom.rb

module Paperclip
  class Custom < Processor
    def initialize file, options = {}, attachment = nil
      super
      @file           = file
      @attachment     = attachment
      @current_format = File.extname(@file.path) 
      @format         = options[:format]
      @basename       = File.basename(@file.path, @current_format)
    end

    def make
      temp_file = Tempfile.new([@basename, @format])
      #geometry = Paperclip::Geometry.from_file(temp_file)
      temp_file.binmode

      if @is_polarized
        run_string =  "convert #{fromfile} -thumbnail 300x400  -bordercolor white -background white  +polaroid  #{tofile(temp_file)}"    
        Paperclip.run(run_string)
      end

      temp_file
    end

    def fromfile
      File.expand_path(@file.path)
    end

    def tofile(destination)
      File.expand_path(destination.path)
    end
  end
end

我从 here 获得了上面的 (custom.rb) 代码。有可能实现吗？如何？提前致谢:)

Answer 1

我转载了你的案例，我认为原因是这里的错字：

has_attached_file :avatar, processors: [:custom], :style => {:original => {}}

应该是:styles而不是:style。如果没有 :styles 选项，回形针不会执行 any post 处理并忽略您的 :processors.

此外，这里有一个非常简单的 Paperclip::Processor 实现 - 将附件转换为灰度。替换 convert 中的命令以执行您自己的 post-processing:

# lib/paperclip_processors/custom.rb
module Paperclip
  class Custom < Processor
    def make
      basename = File.basename(file.path, File.extname(file.path))
      dst_format = options[:format] ? ".\#{options[:format]}" : ''

      dst = Tempfile.new([basename, dst_format])
      dst.binmode

      convert(':src -type Grayscale :dst',
              src: File.expand_path(file.path),
              dst: File.expand_path(dst.path))

      dst
    end
  end
end

如何创建自定义回形针处理器以检索图像尺寸 Rails 4

How to create Custom Paperclip Processor to retrieve image dimensions Rails 4

ruby

ruby-on-rails

processor

dimensions

paperclip