Rails4：如何验证carrierwave上传的图片大小？

Question

我正在使用Rails4和Carrierwave来上传文件，并且我正在使用它。 我来看看这个作品的尺寸，2. Model Level Validation。

我在models \ article.rb中添加了validate :image_size_validation，但出现了NoMethodError in ArticlesController#create。

如何检查图像大小？

我是否应该使用file_size_validator.rb（请参阅How to: Validate attachment file size）而不是上述文章中的解决方案？

任何想法？提前致谢。

\型号\ article.rb

class Article < ActiveRecord::Base 
... 
    has_many :photos, dependent: :destroy 
    validate :image_size_validation 
... 
    private 

    def image_size_validation 
     errors[:image] << "should be less than 1MB" if photos.image.size > 1.megabytes 
    end 

end 

\型号\ photo.rb

class Photo < ActiveRecord::Base 
    belongs_to :article 
    mount_uploader :image, ImageUploader 
end 

\控制器\ article_controller.rb

... 
    def create 
    @article = current_user.articles.build(article_params) 
    if @article.save 
     flash[:success] = "article created!" 
     redirect_to current_user #root_url 
    else 
     @article.build_images 
     render 'new' 
    end 
    end 
... 

文章表

sqlite> .schema articles 
CREATE TABLE "articles" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "content" varchar(255),"user_id" integer, "created_at" datetime, "updated_at" datetime, "category_id" integer); 

照片表

sqlite> .schema photos 
CREATE TABLE "photos" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "article_id" integer,"image" varchar(255), "created_at" datetime, "updated_at" datetime, "bin_image" blob); #prepare bin_image for saving image as binary 

development.log

Started POST "/articles" for 127.0.0.1 at 2014-10-08 19:47:05 +0900 
Processing by ArticlesController#create as HTML 
    Parameters: {"utf8"=>"笨・, "authenticity_token"=>"xxx", "article"=>{"category_id"=>"1718", "photos_attributes"=>{"0"=>{"article_id"=>"", "image"=>#<ActionDispatch::Http::UploadedFile:0x4579140 @tempfile=#<File:C:/xxx/AppData/Local/Temp/RackMultipart20141008-5252-vsv6z>, @original_filename="DSCN0721_080.JPG", @content_type="image/jpeg", @headers="Content-Disposition: form-data; name=\"article[photos_attributes][0][image]\"; filename=\"DSCN0721_080.JPG\"\r\nContent-Type: image/jpeg\r\n">}, "1"=>{"article_id"=>""}, "2"=>{"article_id"=>""}}, "content"=>"test"}, "commit"=>"逋ｻ骭ｲ縺吶ｋ"} 
    [1m[35mUser Load (0.0ms)[0m SELECT "users".* FROM "users" WHERE "users"."remember_token" = 'xxx' LIMIT 1 
    [1m[36m (0.0ms)[0m [1mbegin transaction[0m 
    [1m[35m (0.0ms)[0m rollback transaction 
Completed 500 Internal Server Error in 888ms 

NoMethodError (undefined method `image' for #<ActiveRecord::Associations::CollectionProxy::ActiveRecord_Associations_CollectionProxy_Photo:0x472f8d8>): 
    app/models/article.rb:27:in `image_size_validation' 
    app/controllers/articles_controller.rb:20:in `create' 

编辑

我photo.rb代替article.rb添加image_size_validation，但是当我上传出现错误消息超过1MB的图像。

\型号\ photo.rb

class Photo < ActiveRecord::Base 
    belongs_to :article 
    mount_uploader :image, ImageUploader 

validate :image_size_validation 

    private 

    def image_size_validation 
     #errors[:image] << "should be less than xMB" if image.size > 1.megabytes 
     #add the following code instead of above line 
     if image.size > 1.megabytes 
     errors.add(:base, "Image should be less than 1MB") 
     end 

    end 

end 

\日志\ development.log

Started POST "/articles" for 127.0.0.1 at 2014-10-11 05:50:06 +0900 
Processing by ArticlesController#create as HTML 
    Parameters: {"utf8"=>"笨・, "authenticity_token"=>"xxxx", "article"=>{"categort_id"=>"1718", "photos_attributes"=>{"0"=>{"article_id"=>"", "image"=>#<ActionDispatch::Http::UploadedFile:0x43af760 @tempfile=#<File:C:/xxxx/AppData/Local/Temp/xxxxk>, @original_filename="DSCN0721.JPG", @content_type="image/jpeg", @headers="Content-Disposition: form-data; name=\"article[photos_attributes][0][image]\"; filename=\"DSCN0721.JPG\"\r\nContent-Type: image/jpeg\r\n">}, "1"=>{"article_id"=>""}, "2"=>{"article_id"=>""}}, "content"=>"test"}, "commit"=>"逋ｻ骭ｲ縺吶ｋ"} 
    [1m[35mUser Load (0.0ms)[0m SELECT "users".* FROM "users" WHERE "users"."remember_token" = 'xxxx' LIMIT 1 
    [1m[36m (0.0ms)[0m [1mbegin transaction[0m 
    [1m[35mSQL (3.0ms)[0m INSERT INTO "articles" ("content", "created_at", "category_id", "updated_at", "user_id") VALUES (?, ?, ?, ?, ?) [["content", "test"], ["created_at", Fri, 10 Oct 2014 20:50:08 UTC +00:00], ["category_id", 1718], ["updated_at", Fri, 10 Oct 2014 20:50:08 UTC +00:00], ["user_id", 1]] 
Binary data inserted for `string` type on column `image` 
    [1m[36mSQL (1.0ms)[0m [1mINSERT INTO "photos" ("article_id", "created_at", "image", "updated_at") VALUES (?, ?, ?, ?)[0m [["article_id", 78], ["created_at", Fri, 10 Oct 2014 20:50:08 UTC +00:00], ["image", "xxxx.jpg"], ["updated_at", Fri, 10 Oct 2014 20:50:08 UTC +00:00]] 
    [1m[35m (3.0ms)[0m commit transaction 
Redirected to http://localhost:3000/users/1 
Completed 302 Found in 1306ms (ActiveRecord: 7.0ms) 

Answer 1

试试这个在您的照片型号

validate :image_size_validation, :if => "image?" 

def image_size_validation 
    if image.size > 1.megabytes 
     errors.add(:base, "Image should be less than 1MB") 
    end 
end 

删除private声明

Answer 2

因为1.0版本CarrierWave具有内置的文件大小验证功能。

安装最新carrierwave宝石

gem 'carrierwave', '~> 1.0' 

Add方法size_range提供最小尺寸和最大尺寸

class ImageUploader < CarrierWave::Uploader::Base 
    def size_range 
    0..2.megabytes 
    end 

在模型添加validates_integrity_of到一个有效的文件大小（和内容类型）图片。

class Image < ApplicationRecord 
    mount_uploader :image, ImageUploader 

    validates_integrity_of :image 

Rspec的规范是：

it 'is invalid with an image size greater 2mb' do 
    image = build(:image, image: File.open(File.join(Rails.root, 'spec/support/images/image-3mb.jpg'))) 
    image.valid? 
    expect(image.errors[:image]).to include("File size should be less than 2097152") 
end 

为了使错误消息更友好的替代carrierwave的check_size!方法在ImageUploader。

private 
def check_size!(new_file) 
    size = new_file.size 
    expected_size_range = size_range 
    if expected_size_range.is_a?(::Range) 
     if size < expected_size_range.min 
     raise CarrierWave::IntegrityError, I18n.translate(:"errors.messages.min_size_error", :min_size => ApplicationController.helpers.number_to_human_size(expected_size_range.min)) 
     elsif size > expected_size_range.max 
     raise CarrierWave::IntegrityError, I18n.translate(:"errors.messages.max_size_error", :max_size => ApplicationController.helpers.number_to_human_size(expected_size_range.max)) 
     end 
    end 
    end