Question

我正在使用“GET”方法的表单。我创建了一个文本字段（在testing.html.erb中）供用户输入名称。我希望将名称传递给控制器，并根据名称，我想通过查询从数据库中检索他的数据。这里的问题是我在控制器动作中没有得到任何实例变量（当我在“testing.html.erb”中显示@testing时，屏幕上没有打印任何内容）。下面是我的routes.rb文件。

   Rails.application.routes.draw do
  resources :users

  # The priority is based upon order of creation: first created -> highest priority.
  # See how all your routes lay out with "rake routes".

  # You can have the root of your site routed with "root"
  # root 'welcome#index'

  # Example of regular route:
  get 'index' => 'users#index'
  get 'testing' => 'users#testing'
  # Example of named route that can be invoked with purchase_url(id: product.id)
  #   get 'products/:id/purchase' => 'catalog#purchase', as: :purchase
.....

这是我的testing.html.erb文件

<h1> Testing page </h1>


<%= form_for users_path, :url => {:action => "testing", :name => :name}, :html => {:method => :get} do |f| %>
<%= f.label :first_name %><br />
    <%= f.text_field :name %><br />        
  <%= f.submit "View Schedule" %>
<% end %>

<%= @testing %>
<%#= @testing.email %>
<%#= @testing.content %>

请注意，我在上面的文件中评论了@ testing.email / content来压缩错误（未定义的方法`email'为nil：NilClass）。

以下是我的users_controller.rb文件。

class UsersController < ApplicationController
  before_action :set_user, only: [:show, :edit, :update, :destroy]
  #before_action :user_set, only: [:testing]
  # GET /users
  # GET /users.json
  def index
    @users = User.all
    @test = params[:name]
    @test_index = params[:age]
  end

  # GET /users/1
  # GET /users/1.json
  def show
  end

 def testing
    @testing = User.find_by(name: params[:name])
    #if @testing.name == "Siri"
        # #render text: "Hello #{@testing.name}"
        #redirect_to action: :index
    #end
 end
.........
  private
    # Use callbacks to share common setup or constraints between actions.
    def set_user
      @user = User.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def user_params
      params.require(:user).permit(:name, :email, :content)
    end
end

日志文件显示以下内容。

Processing by UsersController#testing as HTML
  Parameters: {"utf8"=>"✓", "/users"=>{"name"=>"hello rails"}, "commit"=>"View Schedule"}

我还尝试使用强params作为User.find_by（name：params [：users] [：name]），它为nil抛出错误“undefined method` []'：NilClass”。

我想我在某个地方出错了。请指正。谢谢你的时间。

Answer 1

问题在于：

Parameters: {"utf8"=>"✓", "/users"=>{"name"=>"hello rails"}, "commit"=>"View Schedule"}

你看到你的参数中的/users键吗？它不应该在那里。这表明您的表单存在问题：

<%= form_for users_path, :url => {:action => "testing", :name => :name}, :html => {:method => :get} do |f| %>

第一个参数应该是一个字符串（然后用作表格参数的名称）或ActiveModel对象。在您的情况下，它是users_path返回的字符串，仅为'/users'。它应该是@testing

<%= form_for @testing, :url => {:action => "testing", :name => :name}, :html => {:method => :get} do |f| %>

这将解决您当前的问题，在此之后不久您会得到另一个问题，这应该是一个单独的问题。

Answer 2

您最好使用以下内容：

#app/views/users/testing.html.erb
<%= @user.try(:name) %>
<%= form_tag users_testing_path, method: :get do |f| %>
  <%= f.text_field :name %>       
  <%= f.submit "View Schedule" %>
<% end %>

这将允许：

#app/controllers/users_controller.rb
class UsersController < ApplicationController
   def testing
      @user = User.find_by name: params[:name]
   end
end

您也可以改善路线文件：

#config/routes.rb
resources :users, path: "", only: :index, path_names: { index: "index" } do #-> url.com/index
   get :testing, on: :collection #-> url.com/testing
end

Rails 4 Params没有从表单传递给控制器

2 个答案: