ruby-on-rails - 检查用户是否提供了图像？

Question

我正在使用这些 gem 来处理我的图片 uploader :

gem 'carrierwave'
gem 'mini_magick'
gem 'fog'

但是我似乎无法确定图像是否为 nil 或为空，因为它不可能是因为当我调用 @user.picture 时它会返回:

"********@hotmail.co.uk", encrypted_password:

"************************************", reset_password_token: nil, reset_password_sent_at: nil, remember_created_at: nil, sign_in_count: 6, current_sign_in_at: "2016-03-18 11:23:00", last_sign_in_at: "2016-03-18 11:18:16", current_sign_in_ip: "127.0.0.1", last_sign_in_ip: "127.0.0.1", created_at: "2016-03-17 15:00:46", updated_at: "2016-03-18 11:24:13", provider: nil, uid: nil, username: "StormViper", login: nil, cart_id: 1, admin: true, picture: "download.jpg", brand_id: 1, is_brand?: true>, @mounted_as=:picture, @storage=#>, @file=#, @versions={}>

这是我的用户 Controller :

if @user.save
  p "USER SAVED LOGIN: #{@user.username}"
  @cart = Cart.create(:user_id => @user.id, :cart_count => 0)
  @cart.save
  @user.cart_id = @cart.id
  @user.save

  @slot = Slot.create(:cart_id => @cart.id)
  @slot.save
  @cart.slot_id = @slot.id
  @cart.save
  redirect_to root_path
else
  p "USER FAILED LOGIN: #{@user.username}"
  render 'new'
end

我该如何解决这个问题？我无法直接更改返回的 picture.url:

*** NoMethodError Exception: undefined method `url=' for

PictureUploader:0x007f73e6135e78>

我的用户模型包含:

class User < ActiveRecord::Base
  has_one :cart
  has_many :slots, through: :carts
  belongs_to :brand
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable and :omniauthable
  attr_accessor :login
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable,
         :authentication_keys => [:login]
  validates :username, presence: true, uniqueness: true
    def self.find_for_database_authentication(warden_conditions)
      conditions = warden_conditions.dup
      if login = conditions.delete(:login)
        where(conditions.to_hash).where(["lower(username) = :value OR lower(email) = :value", { :value => login.downcase }]).first
      elsif conditions.has_key?(:username) || conditions.has_key?(:email)
        where(conditions.to_hash).first
      end
    end
    mount_uploader :picture, PictureUploader
end

Answer 1

看起来您确实在用户的图片列中保存了一些内容。如果你正在寻找一个 bool 值，我会尝试 @user.picture.present?，如果你正在寻找实际的文件，@user.picture.url.

编辑:#url，而不是 Carrierwave 上传模型上的#file。我有那么一瞬间把工作和家搞混了!