如何在此文件中使用"Form_tag"而不是"Form_for"

Question

我是Ruby on Rails的新手,并且得到了Michael Hartl出色的书籍:Ruby on Rails Tutorial的极大帮助.我已经完成了第8章,现在正在进行该章的练习.我在练习1中遇到(我假设一个典型的"新手")问题.在本练习中,它被问到"1.重写登录表单以使用form_tag代替form_for." 我已经尝试在Stackoverflow,Google,Railscast以及其他许多"网络搜索"中搜索这方面的帮助两天了,我似乎没有找到解决此问题所需的帮助.我试图用form_tag修改的文件如下:

<% provide(:title, "Sign in") %>
<h1>Sign in</h1>

<div class="row">
  <div class="span6 offset3">
    <%= form_for(:session, url: sessions_path) do |f| %>

      <%= f.label :email %>
      <%= f.text_field :email %>

      <%= f.label :password %>
      <%= f.password_field :password %>

      <%= f.submit "Sign in", class: "btn btn-large btn-primary" %>
     <% end %>

    <p>New user? <%= link_to "Sign up now!", signup_path %></p>
  </div>
</div>

我在这个应用程序中使用Rails 3.2.3.任何人都能指出我正确的方向吗？任何人都可以帮我解决这个问题吗？我非常感激.

这是使用form_tag的实现:

<% provide(:title, "Sign in") %>
<h1>Sign in</h1>

<div class="row">
  <div class="span6 offset3">
    <%= form_tag( url: sessions_path ) do  %>

      <%= label_tag :email %>
      <%= text_field_tag :email %>

      <%= label_tag :password %>
      <%= password_field_tag :password %>

      <%= submit_tag "Sign in", class: "btn btn-large btn-primary" %>
    <% end %>

    <p>New user? <%= link_to "Sign up now!", signup_path %></p>
  </div>
</div>

我正在使用Rspec 2.9.0及以下是失败的测试:

describe "signin page" do
    before { visit signin_path }

    it { should have_selector('h1',    text: 'Sign in') }
    it { should have_selector('title', text: 'Sign in') }
  end 

和

describe "with invalid information" do
            before { click_button "Sign in" }

            it { should have_selector('title', text: 'Sign in') }
            it { should have_selector('div.alert.alert-error', text: 'Invalid') }

            describe "after visiting another page" do
              before { click_link "Home" }
              it { should_not have_selector('div.alert.alert-error') }
            end
      end

和

describe "with valid information" do
            let(:user) { FactoryGirl.create(:user) }
            before do
              fill_in "Email",    with: user.email
              fill_in "Password", with: user.password
              click_button "Sign in"
            end

            it { should have_selector('title', text: user.name) }
            it { should have_link('Profile', href: user_path(user)) }
            it { should have_link('Sign out', href: signout_path) }
            it { should_not have_link('Sign in', href: signin_path) }

            describe "followed by signout" do
                    before { click_link "Sign out" }
                    it { should have_link('Sign in') }
            end
      end

这是我的路线文件:

SampleApp::Application.routes.draw do
  resources :users
  resources :sessions, only: [:new, :create, :destroy]


  get "users/new"

  root to: 'static_pages#home'

  match '/signup',  to: 'users#new'
  match '/signin',  to: 'sessions#new'
  match '/signout', to: 'sessions#destroy', via: :delete

  match '/help',    to: 'static_pages#help'
  match '/about',   to: 'static_pages#about'
  match '/contact', to: 'static_pages#contact'
end

Answer 1

我刚刚完成了这个练习,所以我绝不是专家; 但是,这是为我工作并通过所有测试的代码:

../app/views/sessions/new.html.erb

<% provide(:title, "Sign in") %>
<h1>Sign in</h1>

<div class="row">
  <div class="span 6 offset 3">
    <%= form_tag sessions_path do %>

      <%= label_tag :email %>
      <%= text_field_tag :email, params[:email] %>

      <%= label_tag :password %>
      <%= password_field_tag :password %>

      <%= submit_tag "Sign in", class: "btn btn-large btn-primary" %>
    <% end %>

    <p>New User?<%= link_to "Sign Up Now", signup_path %> </p>
  </div>
</div>

我还需要更改../app/controllers/sessions_contoller

class SessionsController < ApplicationController

  def new
  end

  def create
    user = User.find_by_email(params[:email])
    if user && user.authenticate(params[:password])
      session[:user] = user.id
      sign_in user
      redirect_to user
    else
      flash.now[:error] = 'Invalid email/password combination'
      render 'new'
    end  
  end

  def destroy
    sign_out
    redirect_to root_path
  end
end

虽然这有效,但我不完全确定它为什么会这样做; 如果有人能够解释为什么需要控制器的变化,我将不胜感激.我知道这可以作为一个单独的问题提出,但它与OP密切相关,我相信我们都会发现它非常有用,不仅要了解如何使其工作,而且为什么它以这种方式工作.以下是原始视图和控制器文件:

原始'form_for'new.html.erb:

<% provide(:title, "Sign in") %>
<h1>Sign in</h1>

<div class="row">
  <div class="span6 offset3">
    <%= form_for(:session, url: sessions_path) do |f| %>

      <%= f.label :email %>
      <%= f.text_field :email %>

      <%= f.label :password %>
      <%= f.password_field :password %>

      <%= f.submit "Sign in", class: "btn btn-large btn-primary" %>
    <% end %>

    <p>New user? <%= link_to "Sign up now!", signup_path %></p>
  </div>
</div>

和原来的sessions_controller:

class SessionsController < ApplicationController

  def new
  end

  def create
    user = User.find_by_email(params[:session][:email])
    if user && user.authenticate(params[:session][:password])
      sign_in user
      redirect_to user
    else
      flash.now[:error] = 'Invalid email/password combination'
      render 'new'
    end  
  end

  def destroy
    sign_out
    redirect_to root_path
  end
end

Answer 2

我正在研究教程的同一步,你的问题帮助我找到了方向.

使用label和text_field而不是label_tag和text_field_tag工作正常,您不必更改控制器代码(这会生成与原始form_for方法相同的HTML代码).

<%= form_tag(sessions_path) do %>
  <%= label :session, :email %>
  <%= text_field :session, :email %>

  <%= label :session, :password %>
  <%= password_field :session, :password %>

  <%= submit_tag("Sign in", class: "btn btn-large btn-primary") %>
<% end %>

您可以在http://guides.rubyonrails.org/form_helpers.html#dealing-with-model-objects中阅读详细信息