Question

我开始使用rails，所以这是一个相当基本的问题。我正在尝试使用以下代码在主页中呈现登录表单（authlogic）：

视图/家/ index.html.haml：

%p
  This is the home page...!

- if current_user
- else
  = render :template => 'user_sessions/new'

user_sessions_controller：

class UserSessionsController < ApplicationController
  before_filter :require_no_user, :only => [:new, :create]
  before_filter :require_user, :only => :destroy

  def new
    @user_session = UserSession.new
  end

  def create
    @user_session = UserSession.new(params[:user_session])
    if @user_session.save
      flash[:notice] = "Login successful!"
      redirect_back_or_default user_controls_url
    else
      render :action => :new
    end
  end

  def destroy
    current_user_session.destroy
    flash[:notice] = "Logout successful!"
    redirect_back_or_default home_url
  end
end

视图/ user_sessions / new.html.haml

= form_for @user_session, :url => {:action => "create"} do |f|
  = f.error_messages
  %div
    = f.label :login
    = f.text_field :login
  %div
    = f.label :password
    = f.password_field :password
  %div
    = f.check_box :remember_me
    = f.label :remember_me
  %div
    = f.submit "Login"

模型/ user_session.rb

class UserSession < Authlogic::Session::Base

  def to_key
    new_record? ? nil : [ self.send(self.class.primary_key) ]
  end

  httponly true
  secure true
end

当我访问主页时，我得到：

ActionView::Template::Error (undefined method `model_name' for NilClass:Class):
1: = form_for @user_session, :url => {:action => "create"} do |f|
2:   = f.error_messages
3:   %div
4:     = f.label :login
  app/views/user_sessions/new.html.haml:1:in `_app_views_user_sessions_new_html_haml___182031841_97682750'
  app/views/home/index.html.haml:6:in `_app_views_home_index_html_haml__679857083_97787190'

我做错了什么，我该如何解决？

非常感谢你的帮助。

Answer 1

在您的代码中，当您访问与@user_session相关联的new操作时，正在创建user_sessions/new;当您转到index操作时，不会创建它。

当您从user_sessions/new操作中呈现index模板时，ERB / HAML正在查找@user_session的实例，但找不到它，因此错误。

所以，你可以像这样实例化@user_session：

#Note: The <%%> is ERB code (please adjust it for the syntax used in HAML)
<% @user_session = UserSession.new if @user_session.nil? %>

= form_for @user_session, :url => {:action => "create"} do |f|
...

或者，您也可以在index操作本身中执行此操作，但最好将其与index操作保持一致，而不是如上所述（例如，如果您想要的话）从其他一些动作渲染模板 - 然后你会不必要地复制代码）

Rails3：从另一个控制器渲染

1 个答案: