ruby-on-rails - "NoMethodError Table doesn' t存在于禁用PostGres的Rails 5中

Question

我正在构建一个简单的应用程序来从开放的 nasa api 中提取一个 json 对象。

这是我的模型:

class Apod < ApplicationRecord
  def get_apod_info
    apod_url = "https://api.nasa.gov/planetary/apod?api_key=#{ENV['NASA_API_KEY']}"
    response = Net::HTTP.get(URI(apod_url))
    JSON.parse(response)
  end
end

这是我的 Controller :

class ApodController < ApplicationController
  def index
    @apod_info = Apod.get_apod_info
  end
end

当我尝试在浏览器中加载 View 时，底部出现以下错误。

我有一个数据库(我运行 db:create)，但我没有使用它，所以我没有模式也没有迁移。不过这个错误好像和数据库有关？

我尝试了不同的方法(甚至使用模型创建迁移并运行它)，但我无法修复它。我在网上找到的类似错误消息似乎是由与我不同的条件触发的。

有什么想法吗？谢谢!

Processing by ApodController#index as HTML
Completed 500 Internal Server Error in 16ms (ActiveRecord: 0.0ms)


NoMethodError (undefined method `get_apod_info' for Apod(Table doesn't exist):Class):

app/controllers/apod_controller.rb:3:in `index'
  Rendering /Users/aaa/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb within rescues/layout
  Rendering /Users/aaa/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_source.html.erb
  Rendered /Users/aaa/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_source.html.erb (5.1ms)
  Rendering /Users/aaa/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb
  Rendered /Users/aaa/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (1.4ms)
  Rendering /Users/aaa/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb
  Rendered /Users/aaa/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (0.8ms)

Answer 1

如果 Apod 不是数据库支持的模型，那么尝试使用一个普通的旧 ruby​​ 对象，例如(是的，这应该是一个类方法，而不是实例方法):

class Apod
  def self.get_apod_info
    apod_url = "https://api.nasa.gov/planetary/apod?api_key=#{ENV['NASA_API_KEY']}"
    response = Net::HTTP.get(URI(apod_url))
    JSON.parse(response)
  end
end

就我个人而言，我喜欢这种风格:

class Apod
  class << self

    def get_apod_info
      apod_url = "https://api.nasa.gov/planetary/apod?api_key=#{ENV['NASA_API_KEY']}"
      response = Net::HTTP.get(URI(apod_url))
      JSON.parse(response)
    end

  end
end

但是，这是一个品味问题，我知道有些人不喜欢它。