在rails中使用Presenter

Question

json = JSON.parse(response.body)
    @games = json['machine-games']

    paging = json['paging']
    if paging
      if paging['next']
        next_page_query = paging['next'].match(/\?.*/)[0]
      @next_page = "/machine_games/search#{next_page_query}"
    end

    if paging['previous']
      previous_page_query = paging['previous'].match(/\?.*/)[0]
      @previous_page = "/machine_games/search#{previous_page_query}"
    end
  end

上面是controller.How中show方法的一小段逻辑，我是否将其移动到展示者，以便它将持有machine_games JSON响应，并提供访问游戏和下一页/上一页链接(以及它们是否存在)的方法。{不太熟悉演示者模式}

Answer 1

让我们创建一个用于将JSON响应解析为@games、@next_page和@previous_page的presenter。

# app/presenters/games_presenter.rb

class GamesPresenter

  attr_reader :games, :next_page, :previous_page

  def initialize json
    @games = json['machine-games']

    paging = json['paging']
    if paging && paging['next']
      next_page_query = paging['next'].match(/\?.*/)[0]
      @next_page = "/machine_games/search#{next_page_query}"
    end

    if paging && paging['previous']
      previous_page_query = paging['previous'].match(/\?.*/)[0]
      @previous_page = "/machine_games/search#{previous_page_query}"
    end
  end

end

现在，您的控制器操作应该如下所示：

def show
  # ...
  @presenter = GamesPresenter.new(json)
end

你可以在你的视图中使用它：

<% @presenter.games.each do |game| %>
  ...
<% end %>

<%= link_to "Previous", @presenter.previous_page %>
<%= link_to "Next", @presenter.next_page %>

为了告诉Rails加载apps/presenters/目录以及model/、controller/、views/等，请将以下内容添加到config/application.rb：

config.after_initialize do |app|
  app.config.paths.add 'app/presenters', :eager_load => true
end