Question

我有一个控制器'news_controller.rb'用于与数据库连接。当我尝试创建数据库行项目（我通过自动脚本发出请求）时，我收到以下错误

ActionController::ParameterMissing (param is missing or the value is empty: news): app/controllers/api/news_controller.rb:57:in `news_params'app/controllers/api/news_controller.rb:28:in `create'

当我在创建操作中使用params [：category]，params [：headline]等时，它可以正常工作。有什么可能的原因和解决方案？

这是我的控制器代码：

module Api
    class NewsController < Api::ApiController
        respond_to :json

        def index
            @news = News.all
            respond_with :news => @news
        end

        def show
            @news = News.find(params[:id])
            respond_with :news => @news
        end

        def new
          @news = News.new
          respond_with :news => @news
        end

        def edit
            @news = News.find(params[:id])
            respond_with :news => @news
        end

        def create
            if !News.exists?(headline: params[:headline])
                #@news = News.new(:category => params[:category], :headline => params[:headline], :content => params[:content], :image_url => params[:image_url])
                @news = News.new(news_params)
                if @news.save
                    respond_with :news => @news
                else
                    respond_with @news.errors
                end
            end
        end

        def update
          @news = News.find(params[:id])

          if @news.update(news_params)
            respond_with :news => @news
          else
            respond_with @news.errors
          end
        end

        def destroy
          @news = News.find(params[:id])
          @news.destroy
          respond_to do |format|
            format.json { head :no_content }
          end
        end

        private
          def news_params
            params.require(:news).permit(:category, :headline, :content, :image_url)
          end
    end
end

Answer 1

您的params有值

params = { category: 'value', headline: 'value', .... }

当您使用news_params时，您希望您的参数格式化为

params = { news: { category: 'value', headline: 'value', .... }}

但事实并非如此。

这就是使用

时的原因

@news = News.new(:category => params[:category], :headline => params[:headline], :content => params[:content], :image_url => params[:image_url])

并不适用于

@news = News.new(news_params)
# news_params is nil

Param缺少Rails 4

1 个答案: