ruby-on-rails - 没有路由匹配 { :action= >"show", :controller= >"schools"} 缺少必需的键:[:id]

Question

我不知道为什么我无法为项目中的每所学校创建信息链接。这是完整的错误:

No route matches {:action=>"show", :controller=>"schools"} missing required keys: [:id] <%= link_to "Info", school_path, class: "btn btn-info" %>

这是我的index.html.erb:

    <% @schools.each do |school| %>
      <%= school.name %>
      <%= link_to "Info", school_path, class: "btn btn-info" %>
      <br>
    <% end %>

schools_controller.rb:

class SchoolsController < ApplicationController
  def show
    @school = School.find(params[:id])
  end

  def new
    @school = School.new
  end

  def edit
    @school = School.find(params[:id])
  end

  def index
    @schools = School.all
  end

  def create
    @school = School.new(school_params)

    @school.save
    redirect_to @school
  end

  private

    def school_params
      params.require(:school).permit(:name)
    end
end  

Answer 1

因为您正在学习，所以我会给您一些背景信息。

--

No route matches

该错误意味着您的 Rails routes找不到您引用的路线。

它给出了以下规范:

missing required keys: [:id]

这意味着该路线存在，但您尚未填写id参数。

--

为了帮助您了解其工作原理，请考虑 following :

   GET          /photos             photos#index    display a list of all photos
   GET          /photos/new         photos#new      return an HTML form for creating a new photo
   POST         /photos             photos#create   create a new photo
>> GET          /photos/:id         photos#show     display a specific photo
   GET          /photos/:id/edit    photos#edit     return an HTML form for editing a photo
   PATCH/PUT    /photos/:id         photos#update   update a specific photo
   DELETE       /photos/:id         photos#destroy  delete a specific photo

这些是使用 Rails 中的 resources 指令创建的路由。我现在不会解释它 - 只是说当您调用 school_path 时，您指的是 route 的 GET/schools/:id 路径。

因此，您必须记住的是，当您调用此路由时，您必须向其发送一个id - url.com/schools/1 。这允许 Controller 查找适当的记录 (School.find params[:id])。

当你打电话时...

<%= link_to "Info", school_path, class: "btn btn-info" %>

...您没有将任何参数传递给 school_path。

要修复它，您必须传递id，如果您传递适当的对象，Rails 会自动执行此操作:

<%= link_to "Info", school_path(school), class: ".." %>

或

<%= link_to "Info", school, class: "..." %>