ruby-on-rails – 条件转换选项回形针

在 some research之后,我能够根据我的image_class列添加样式.

Model.rb

has_attached_file :image,:styles => lambda { |attachment| attachment.instance.decide_styles }

def decide_styles
  styles = {}

  case self.image_class
    when "poster"
      styles[:thumb] = ["30x45!",:jpg]
      styles[:standard] = ["185x278!",:jpg]
      styles[:expanded] = ["372x559!",:jpg]
      styles[:big] = ["600x900!",:jpg]
    when "cover"
      styles[:thumb] = ["30x45!",:jpg]
      styles[:standard] = ["300x1200!",:jpg]
  end

  styles
end

这很顺利,现在我也想添加条件convert_options.这种方式失败了.

has_attached_file :image,:styles => lambda { |attachment| attachment.instance.decide_styles },:convert_options => lambda { |attachment| attachment.instance.decide_convert_options }

def decide_styles
  ...
end

def decide_convert_options

  opshunz = {}
  case self.image_class
    when "poster"
      opshunz[:thumb] = "-flop"
      opshunz[:standard] = "-flop"
      opshunz[:expanded] = "-flop"
      opshunz[:big] = "-flop"

    when "cover"
      opshunz[:thumb] = "-enhance"
      opshunz[:standard] = "-enhance"
  end

  opshunz
end

错误：

NoMethodError: undefined method `instance' for :all:Symbol

from /Users/AnsPoluke/Sites/nulike/app/models/movie_image.rb:8:in `block in <class:MovieImage>'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:431:in `[]'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:431:in `process_options'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:423:in `extra_options_for'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/style.rb:56:in `convert_options'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/style.rb:79:in `block in processor_options'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/style.rb:78:in `each'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/style.rb:78:in `processor_options'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:462:in `block in post_process_style'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:461:in `each'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:461:in `inject'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:461:in `post_process_style'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:454:in `block in post_process_styles'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:453:in `each'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:453:in `post_process_styles'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:445:in `block (2 levels) in post_process'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/activesupport-4.0.2/lib/active_support/callbacks.rb:393:in `_run__3861360263242897910__image_post_process__callbacks'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/activesupport-4.0.2/lib/active_support/callbacks.rb:80:in `run_callbacks'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/callbacks.rb:36:in `run_paperclip_callbacks'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:443:in `block in post_process'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/activesupport-4.0.2/lib/active_support/callbacks.rb:383:in `_run__3861360263242897910__post_process__callbacks'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/activesupport-4.0.2/lib/active_support/callbacks.rb:80:in `run_callbacks'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/callbacks.rb:36:in `run_paperclip_callbacks'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:442:in `post_process'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/attachment.rb:114:in `assign'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/paperclip-4.1.1/lib/paperclip/has_attached_file.rb:66:in `block in define_setter'
from (irb):2
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/railties-4.0.2/lib/rails/commands/console.rb:90:in `start'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/railties-4.0.2/lib/rails/commands/console.rb:9:in `start'
from /Users/AnsPoluke/.rvm/gems/ruby-2.1.0/gems/railties-4.0.2/lib/rails/commands.rb:62:in `<top (required)>'
from bin/rails:4:in `require'

任何想法为什么它与样式完美配合但转换失败？

解决方法

注意：尚未验证工作代码

似乎传入块的参数：convert_options已经是一个实例,而不是附件(而不是样式选项,它是一个附件)

尝试：

convert_options: lambda { |instance| instance.decide_convert_options }

如果你提取配置数据,你的代码会更好看,例如：

has_attached_file :image,styles: lambda { |attachment| attachment.instance.image_options[:styles] },convert_options: lambda { |instance| instance.image_options[:convert_options] }


IMAGE_OPTIONS = {
  poster: {
    styles: {
      thumb: ["30x45!",:jpg],standard: ["185x278!",expanded: ["372x559!",:jpg]
      big: ["600x900!",:jpg]
    },convert_options: {
      thumb: "-flop",standard: "-flop",expanded: "-flop",big: = "-flop"
    }
  },cover: {
    styles: {
      thumb: ["30x45!",standard: ["300x1200!",convert_options: {
      thumb: "-enhance",standard: "-enhance"
    }
  }
}

def image_options
  IMAGE_OPTIONS[self.image_class]
end

我希望有所帮助

更新：

看起来你的convert_options没有在这里设置：
https://github.com/thoughtbot/paperclip/blob/a93dfc773b4fd649db4d1281b42a2a71b1ae72ff/lib/paperclip/style.rb#L55

看起来他们建议传递带有样式的convert_options,如本规范：https://github.com/thoughtbot/paperclip/blob/263a498195d47563a6227be18cf4463c4c6e7903/spec/paperclip/style_spec.rb#L41

你能试试吗？所以完全删除convert_options,并在您的配置中返回哈希,如：

IMAGE_OPTIONS = {
      poster: {
        styles: {
          thumb: {
            geometry: "30x45!",format: :jpg,convert_options: '-flop',},standard: {...}
          expanded: {...}
          big: {...}
        }
      },cover: {
        styles: {...}