Rails 4 Params没有从表单传递给控制器

Question

I am using a form for "GET" method. I created a text field (in testing.html.erb) for user to enter the name. I want the name to be passed into the controller and based on the name, I want to retrieve his data from the database through a query. The problem here is that I am not getting anything into the instance variable in the controller action (Nothing is printed on screen when I display @testing in "testing.html.erb"). Below is my routes.rb file.

   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
.....

This is my testing.html.erb file

<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 %>

Please note that I commented @testing.email/content in above file to supress the error (undefined method `email' for nil:NilClass).

Below is my users_controller.rb file.

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

The log-file shows the following.

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

I also tried to use strong params as User.find_by(name: params[:users][:name]) which throws error "undefined method `[]' for nil:NilClass".

I think I am going wrong somewhere. Please correct me. Thank you for your time.

Answer 1

Issue lies here:

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

Do you see /users key in your params? It shoudn't be there. This indicates problem with your form:

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

First argument is expected to be a string (which is then used as a name of form params) or ActiveModel object. In your case, it is string returned by users_path , which is just '/users' . It should be @testing

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

That will fix your current issue, you will get another shortly after that, which should go into a separate question.

Answer 2

You'll be best using the following:

#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 %>

This will allow:

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

---

You could improve your routes file too:

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