无法将用户与书籍关联(无法访问用户 ID)
我正在使用设计来注册和验证用户。我想要完成的是让用户登录并能够在他的个人资料中添加一本书。稍后当他重新登录时将显示该书。所以在我的应用程序我有用户模型和书籍模型。但是我在其中一个控制器中访问用户时遇到问题。我收到一个异常 nil:NilClass 的未定义方法“books”。
查看
主页#index
<p >Welcome to the new generation</p>
<p><%= link_to "Add new Book",:controller =>"book", :action => 'new' %></p>
<% @books.each do |b| %>
<p><%= b.author%></p>
<p><%= b.title%></p>
<%end%>
家庭控制器
class HomeController < ApplicationController
def index
@user = current_user
@user.books||=Book.new
@[email protected]
end
end
图书控制器
class BookController < ApplicationController
def new
@books = Book.new
# redirect_to :controller=>"home" ,:action=>"index"
end
def create
@books = Book.new(params[:book])
if @books.save
render "home/index"
#redirect_to :controller=>"home" ,:action=>"index"
else
render :action => 'new'
end
end
图书视图
<h1>Book#new</h1>
<%= form_for(:book) do |f| %>
<p><%= f.text_field :title %></p>
<p><%= f.text_field :author %></p>
<p><%= f.submit "Add book"%>
图书模型
class Book < ActiveRecord::Base
belongs_to :user
end
用户模型
class User < ActiveRecord::Base
has_many :books
# Include default devise modules. Others available are:
# :token_authenticatable, :lockable, :timeoutable and :activatable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
# Setup accessible (or protected) attributes for your model
attr_accessible :email, :password, :password_confirmation,:firstname,:lastname,:school,:major,:sex,:zipcode
end
路由
Campus::Application.routes.draw do
get "book/index"
get "book/edit"
get "book/new"
get "home/edit"
devise_for :users
resources :book
root :to=> "home#index"
match '/book/new' =>"home#index"
end
创建表
class CreateBooks < ActiveRecord::Migration
def self.up
create_table :books do |t|
t.text :title
t.text :author
t.integer :user_id, :null => false
t.timestamps
end
add_foreign_key(:books, :users)
end
def self.down drop_table:书籍 删除外键(:书籍,:用户) 结尾 结束
数据库模式
ActiveRecord::Schema.define(:version => 20110609055608) do
create_table "books", :force => true do |t|
t.text "title"
t.text "author"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "courses", :force => true do |t|
t.string "name"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "strong_ins", :force => true do |t|
t.string "subject"
t.string "topic"
t.text "description"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "users", :force => true do |t|
t.string "email", :default => "", :null => false
t.string "encrypted_password", :limit => 128, :default => "", :null => false
t.string "password_salt", :default => "", :null => false
t.string "reset_password_token"
t.string "remember_token"
t.datetime "remember_created_at"
t.integer "sign_in_count", :default => 0
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.datetime "created_at"
t.datetime "updated_at"
t.string "firstname"
t.string "lastname"
t.text "school"
t.text "major"
t.string "sex"
t.integer "zipcode"
end
add_index "users", ["email"], :name => "index_users_on_email", :unique => true
add_index "users", ["reset_password_token"], :name => "index_users_on_reset_password_token", :unique => true
create_table "weak_ins", :force => true do |t|
t.string "subject"
t.string "topic"
t.text "description"
t.datetime "created_at"
t.datetime "updated_at"
end
end
i am using devise to register and authenticate users.What i am trying to acomplish is for a user to sign in and be able to add a book in his profile.And later when he sign back in the book will be shown.So in my application i have user model and book model.But i am having a problem accessing user in one of the controller.I am getting a exception undefined method `books' for nil:NilClass.
VIEW
Home#index
<p >Welcome to the new generation</p>
<p><%= link_to "Add new Book",:controller =>"book", :action => 'new' %></p>
<% @books.each do |b| %>
<p><%= b.author%></p>
<p><%= b.title%></p>
<%end%>
HOME CONTROLLER
class HomeController < ApplicationController
def index
@user = current_user
@user.books||=Book.new
@[email protected]
end
end
BOOK CONTROLLER
class BookController < ApplicationController
def new
@books = Book.new
# redirect_to :controller=>"home" ,:action=>"index"
end
def create
@books = Book.new(params[:book])
if @books.save
render "home/index"
#redirect_to :controller=>"home" ,:action=>"index"
else
render :action => 'new'
end
end
BOOK VIEW
<h1>Book#new</h1>
<%= form_for(:book) do |f| %>
<p><%= f.text_field :title %></p>
<p><%= f.text_field :author %></p>
<p><%= f.submit "Add book"%>
BOOK MODEL
class Book < ActiveRecord::Base
belongs_to :user
end
USER MODEL
class User < ActiveRecord::Base
has_many :books
# Include default devise modules. Others available are:
# :token_authenticatable, :lockable, :timeoutable and :activatable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
# Setup accessible (or protected) attributes for your model
attr_accessible :email, :password, :password_confirmation,:firstname,:lastname,:school,:major,:sex,:zipcode
end
ROUTE
Campus::Application.routes.draw do
get "book/index"
get "book/edit"
get "book/new"
get "home/edit"
devise_for :users
resources :book
root :to=> "home#index"
match '/book/new' =>"home#index"
end
CREATE TABLE
class CreateBooks < ActiveRecord::Migration
def self.up
create_table :books do |t|
t.text :title
t.text :author
t.integer :user_id, :null => false
t.timestamps
end
add_foreign_key(:books, :users)
end
def self.down
drop_table :books
remove_foreign_key(:books, :users)
end
end
DB SCHEMA
ActiveRecord::Schema.define(:version => 20110609055608) do
create_table "books", :force => true do |t|
t.text "title"
t.text "author"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "courses", :force => true do |t|
t.string "name"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "strong_ins", :force => true do |t|
t.string "subject"
t.string "topic"
t.text "description"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "users", :force => true do |t|
t.string "email", :default => "", :null => false
t.string "encrypted_password", :limit => 128, :default => "", :null => false
t.string "password_salt", :default => "", :null => false
t.string "reset_password_token"
t.string "remember_token"
t.datetime "remember_created_at"
t.integer "sign_in_count", :default => 0
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.datetime "created_at"
t.datetime "updated_at"
t.string "firstname"
t.string "lastname"
t.text "school"
t.text "major"
t.string "sex"
t.integer "zipcode"
end
add_index "users", ["email"], :name => "index_users_on_email", :unique => true
add_index "users", ["reset_password_token"], :name => "index_users_on_reset_password_token", :unique => true
create_table "weak_ins", :force => true do |t|
t.string "subject"
t.string "topic"
t.text "description"
t.datetime "created_at"
t.datetime "updated_at"
end
end
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要使用设备获取控制器中当前登录的用户,只需使用
current_user
变量即可。另外,User 和 Book 之间的关系是has_many :books
,因此 current_user.book 不存在。To get the currently logged in user in controllers using devise you simply use the
current_user
variable. Also, the relationship between User and Book ishas_many :books
so current_user.book doesn't exist.