我使用Rails4和Carrierwave上传文件，我让它正常工作。 我来看看下面这个aritcle 2. Model Level Validation。
来检查图像大小我在models \ article.rb中添加了validate :image_size_validation，但NoMethodError in ArticlesController#create已出现。
如何查看图像尺寸？
我应该使用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吗？
有什么想法吗？提前谢谢。
\模型\ 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
\模型\ 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'
修改
我在photo.rb中添加了image_size_validation而不是article.rb，但是当我上传超过1MB的图片时没有出现错误消息。
\模型\ 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
\ LOG \ 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)
答案 0 :(得分：7)
在你的照片模型中试试这个
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
答案 1 :(得分：4)
由于1.0版本CarrierWave具有内置文件大小验证。
安装最新的carrierwave gem
gem 'carrierwave', '~> 1.0'
添加方法size_range以提供最小尺寸和最大尺寸
class ImageUploader < CarrierWave::Uploader::Base
def size_range
0..2.megabytes
end
在模型中添加validates_integrity_of以有效图像的文件大小（和内容类型）。
class Image < ApplicationRecord
mount_uploader :image, ImageUploader
validates_integrity_of :image
Rspec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
要使错误消息更友好，请覆盖check_size!中的carrierwave ImageUploader方法。
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