如何使用属于另一个模型的模型的控制器的索引动作？

Question

我正在编写Rails应用程序，以处理大学课程的日程安排。当前，我正在尝试建立索引页面以显示数据库中的所有部分，但出现此错误：

No route matches {:action=>"index", :controller=>"sections"}

但是，当我查看路线时，可以看到节和索引的控制器动作对。

bin/rails routes
               Prefix Verb   URI Pattern                                                                              Controller#Action
           home_index GET    /home/index(.:format)                                                                    home#index
      course_sections GET    /courses/:course_id/sections(.:format)                                                   sections#index
                      POST   /courses/:course_id/sections(.:format)                                                   sections#create
   new_course_section GET    /courses/:course_id/sections/new(.:format)                                               sections#new
  edit_course_section GET    /courses/:course_id/sections/:id/edit(.:format)                                          sections#edit
       course_section GET    /courses/:course_id/sections/:id(.:format)                                               sections#show
                      PATCH  /courses/:course_id/sections/:id(.:format)                                               sections#update
                      PUT    /courses/:course_id/sections/:id(.:format)                                               sections#update
                      DELETE /courses/:course_id/sections/:id(.:format)                                               sections#destroy
              courses GET    /courses(.:format)                                                                       courses#index
                      POST   /courses(.:format)                                                                       courses#create
           new_course GET    /courses/new(.:format)                                                                   courses#new
          edit_course GET    /courses/:id/edit(.:format)                                                              courses#edit
               course GET    /courses/:id(.:format)                                                                   courses#show
                      PATCH  /courses/:id(.:format)                                                                   courses#update
                      PUT    /courses/:id(.:format)                                                                   courses#update
                      DELETE /courses/:id(.:format)                                                                   courses#destroy
             students GET    /students(.:format)                                                                      students#index
                      POST   /students(.:format)                                                                      students#create
          new_student GET    /students/new(.:format)                                                                  students#new
         edit_student GET    /students/:id/edit(.:format)                                                             students#edit
              student GET    /students/:id(.:format)                                                                  students#show
                      PATCH  /students/:id(.:format)                                                                  students#update
                      PUT    /students/:id(.:format)                                                                  students#update
                      DELETE /students/:id(.:format)                                                                  students#destroy
                 root GET    /                                                                                        home#index
   rails_service_blob GET    /rails/active_storage/blobs/:signed_id/*filename(.:format)                               active_storage/blobs#show
rails_blob_representation GET    /rails/active_storage/representations/:signed_blob_id/:variation_key/*filename(.:format) active_storage/representations#show
   rails_disk_service GET    /rails/active_storage/disk/:encoded_key/*filename(.:format)                              active_storage/disk#show
update_rails_disk_service PUT    /rails/active_storage/disk/:encoded_token(.:format)                                      active_storage/disk#update
 rails_direct_uploads POST   /rails/active_storage/direct_uploads(.:format)                                                 active_storage/direct_uploads#create

为什么它不能正确路由？

我的节控制器看起来像这样：

class SectionsController < ApplicationController

    def index
        @courses = Course.all
    end

    def create
        @course = Course.find(params[:course_id])
        @section = @course.sections.create(section_params)
    end

    def update
        @course = Course.find(params[:course_id])
        @section = @course.sections.find(params[:id])
        @section.update(section_params)
    end

    def destroy
        @course = Course.find(params[:course_id])
        @section = @course.sections.find(params[:id])
        @section.destroy
    end

    private
        def section_params
            params.require(:section).permit(:section_letter, :section_professor, :section_meetings, :section_capacity)
        end
end

sections文件夹中的My index.html.erb视图如下：

<h2>Sections</h2>

<table>
    <tr>
        <th>Number</th>
        <th>Section</th>
        <th>Name</th>
        <th>Credit Hours</th>
        <th>Professor</th>
        <th>Meetings</th>
        <th>Capacity</th>
    </tr>
    <% @courses.each do |course| %>
        <% course.sections.each do |section| %>
            <tr>
                <td><%= course.course_num %></td>
                <td><%= section.section_letter %></td>
                <td><%= course.course_name %></td>
                <td><%= course.course_credits %></td>
                <td><%= section.section_professor %></td>
                <td><%= section.section_meetings %></td>
                <td><%= section.section_capacity %></td>
            </tr>
        <% end %>
    <% end %>

</table>

而且我的路线文件看起来像：

Rails.application.routes.draw do
  get 'home/index'

  resources :courses do
    resources :sections
  end
  resources :students

  root 'home#index'
end

感谢您的任何帮助！

Answer 1

这是因为sections控制器是课程资源下的嵌套资源。有一个sections#index，但它带有一个:course_id参数。

换句话说，没有/sections路径直接映射到sections#index

如果是一次性端点，则可以声明此路由

get 'sections' => 'sections#index', as: :sections

然后您需要更新#index中的SectionsController方法，并像拉所有的节一样>]

@sections = Section.all