Rails 5 个常量 & 模型 & 虚拟属性

Question

我正在尝试在模型虚拟属性中使用预定义常量。

当我创建用户时，它显示绝对 avatar_url 并且工作正常。

问题：

当我在登录方法中找到用户时，它 return 只是相对的 url 即 "avatar_url": "/avatars/original/missing.png" 这意味着 #{SERVER_BASE_PATH} 在那一刻没有插入。

它也适用于某些 api 调用，即更新用户时。但并非在所有情况下。请帮我解决这个问题，以便在所有 api 次调用中获得绝对 url

示例：

型号：

class User < ApplicationRecord
    # user model
    # if avatar url is empty then use default image url
    # SERVER_BASE_PATH is defined in config/initializer/constant.rb
    attribute :avatar_url, :string, default: -> { "#{SERVER_BASE_PATH}/avatars/original/missing.png" }
end

控制器：

登录方式简单

class UsersController < ApplicationController
    def login
        response = OK()
        unless params[:email].present? and params[:password].present?
            render json: missing_params_specific('either user [email] or [password]') and return
        end
        response[:user] = []
        response[:status] = '0'

        begin
        user = User.find_by(email: params[:email].downcase)
        if user && user.authenticate(params[:password])
            # following line first check if user profile image exist then it places that image url given by paperclip
            # if not exist then url defined in model virtual attributes is used.
            user.avatar_url = user.avatar.url if user.avatar.url.present?
            user.set_last_sign_in_at user.sign_in_count
          response[:user] = user
          response[:status] = '1'
        else
          response[:message] = 'Invalid email/password combination' # Not quite right!
        end
        rescue => e
            response[:message] = e.message
        end
        render json: response and return
    end
end

API JSON 响应：

{
  "JSON_KEY_STATUS_CODE": 1,
  "JSON_KEY_STATUS_MESSAGE": "OK",
  "server_time": 1490623384,
  "user": {
    "confirmed": true,
    "user_status": "Active",
    "admin": false,
    "user_role": "Standard",
    "first_name": "Super",
    "last_name": "User",
    "full_name": "Super User",
    "avatar_url": "/avatars/original/missing.png",  <-- Here (not absolute url)
    "is_active": true,
  },
  "status": "1"
}

Answer 1

据我了解，JSON 响应中的 "avatar_url" 属性是您在与 Paperclip 集成的模型中定义的 default_url：

class User < ActiveRecord::Base
  has_attached_file :avatar, 
                    styles: { medium: "300x300>", thumb: "100x100>" },
                    default_url: "/images/:style/missing.png"
  validates_attachment_content_type :avatar, content_type: /\Aimage\/.*\z/
end

你试过用你 SERVER_BASE_PATH 设置 default_url 吗？

Rails 5 个常量 & 模型 & 虚拟属性

Rails 5 Constant & Model & Virtual Attributes

model

ruby-on-rails

constants

virtual-attribute