重命名图像 - 回形针

Question

代码

在我的图像模型：

has_attached_file :pic 
before_post_process :rename_pic 
before_save ->{ p 'before_save ----------------' } 
after_post_process ->{ p 'after_post_process --------------' } 

    def rename_pic 
    p 'en imagen' 
    p self 
    p 'en imagen' 
    end 

在服务，有很多图片：

# don't use accepts_nested_attributes_for 
    before_save :create_images 
    attr_accessor :images_attributes 

    def create_images 
    # images_attributes example value: { "0"=> {img_attrs}, "1" => {img_attrs1} } 
    images_attributes.all? do |k, image_attrs| 
     if image_attrs.delete(:_destroy) == "false" 
     p 'asd' 
     image = Image.new image_attrs.merge(service_id: id) 
     p image.service 
     p image.service_id 
     image.save 
     end 
    end 
    end 

这是输出我得到：

"asd" 
"en imagen" 
#<Image id: nil, service_id: nil, pic_file_name: "Screen_Shot_2013-04-07_at_5.18.03_PM.png", pic_content_type: "image/png", pic_file_size: 16041, pic_updated_at: "2013-07-30 22:58:46", created_at: nil, updated_at: nil, user_id: nil> 
"en imagen" 
G"after_post_process --------------" 
#<Service id: 427, event_id: nil, min_capacity: nil, max_capacity: nil, price: #<BigDecimal:7fb6e9d73d48,'0.0',9(18)>, image_path: nil, name: "Super Franks", desc: "zxc", created_at: "2013-05-12 19:01:54", updated_at: "2013-07-30 19:32:48", address: "pasadena", longitude: 77.225, latitude: 28.6353, gmaps: true, city: "san francisco", state: "california", country_id: "472", tags: "Banquet", created_by: 22, avg_rating: #<BigDecimal:7fb6efdbcf10,'0.0',9(18)>, views: 27, zip_code: "", address2: "", price_unit: "", category_id: 3, featured: true, publish: true, slug: "banquet-super-franks", discount: nil, currency_code: "USD", video_url: "http://www.youtube.com/watch?v=A3pIrBZQJvE", short_description: ""> 
427 
"before_save ----------------" 

问题

当调用

image = Image.new image_attrs.merge(service_id: id) 

回形针似乎开始处理，然后设置的service_id。

所以当我尝试使用service里面rename_pic服务是nil。

有关如何处理此问题的任何想法？

Answer 1

这解决了我的问题，我改变了：

before_post_process :rename_pic 

到：

before_create :rename_pic 

，这是rename_pic，备案：

def rename_pic 
    extension = File.extname(pic_file_name).downcase 
    self.pic.instance_write :file_name, 
    "#{service.hyphenated_for_seo}#{extension}" 
end 

其中servicehas_manyimages，和imagebelongs_toservice。

Answer 2

要当心与@juanpastas的修复，因为如果你改变before_post_process到before_create，只会当你创建你的形象运行，不是当你更新。有回调仍然在更新运行，这样做：

class YourImage 
    has_attached_file :pic 

    # use both callbacks 
    before_create      :rename_pic 
    before_post_process    :rename_pic 

    def rename_pic 
    # assotiated_object is the association used to get pic_file_name 
    return if self.assotiated_object.nil? 

    extension = File.extname(pic_file_name).downcase 
    self.pic.instance_write :file_name, 
     "#{service.hyphenated_for_seo}#{extension}" 
    end 
end