我一直在关注创建Rails博客（http://www.roberthuberdeau.com/articles/4-How-to-create-a-blog-in-Ruby-on-Rails-3）的教程，并且基本上已经一直到最后。
然而，在所有的迁移之后，我现在正在努力。每当我完成以前用于创建文章的表单时，我都无法在索引页面上看到它们。我已经挖出来并且相信错误的根源是当我按下“创建文章”时我没有保存任何文章。
为了测试这个，我使用控制台创建了一篇文章，它应该出现，因此我认为问题出现在创建文章的形式和控制器之间（尽管我很乐意对此进行更正）。
每当我尝试下面的日志中都会出现以下内容：
Started POST "/articles" for 127.0.0.1 at 2013-04-01 21:12:58 +0100
Processing by ArticlesController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"XLeHm+4Tgd6n9vt4RxAQ5YVTbWTi+UnqkmBso9Iuo+4=", "article"=>{"title"=>"I rule", "body"=>"Change teams.", "tag_names"=>"kill", "published"=>"1"}, "commit"=>"Create Article"}
User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = 1 LIMIT 1
Role Load (0.1ms) SELECT "roles".* FROM "roles" INNER JOIN "roles_users" ON "roles"."id" = "roles_users"."role_id" WHERE "roles_users"."user_id" = 1 AND "roles"."name" = 'Admin' LIMIT 1
Role Load (0.1ms) SELECT "roles".* FROM "roles" INNER JOIN "roles_users" ON "roles"."id" = "roles_users"."role_id" WHERE "roles_users"."user_id" = 1 AND "roles"."name" = 'Moderator' LIMIT 1
Role Load (0.1ms) SELECT "roles".* FROM "roles" INNER JOIN "roles_users" ON "roles"."id" = "roles_users"."role_id" WHERE "roles_users"."user_id" = 1 AND "roles"."name" = 'Member' LIMIT 1
Redirected to http://localhost:3000/
Completed 302 Found in 5ms (ActiveRecord: 0.5ms)
使用数据库架构：
ActiveRecord::Schema.define(:version => 20130401171646) do
create_table "articles", :force => true do |t|
t.string "title"
t.text "body"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
t.integer "user_id", :null => false
t.boolean "published", :default => false
end
create_table "comments", :force => true do |t|
t.integer "article_id"
t.string "name"
t.string "email"
t.text "body"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
create_table "roles", :force => true do |t|
t.string "name"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
create_table "roles_users", :id => false, :force => true do |t|
t.integer "role_id"
t.integer "user_id"
end
create_table "taggings", :force => true do |t|
t.integer "article_id"
t.integer "tag_id"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
create_table "tags", :force => true do |t|
t.string "name"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
create_table "users", :force => true do |t|
t.string "email", :default => "", :null => false
t.string "encrypted_password", :default => "", :null => false
t.string "reset_password_token"
t.datetime "reset_password_sent_at"
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", :null => false
t.datetime "updated_at", :null => false
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
end
文章控制者：
class ArticlesController < ApplicationController
before_filter :authenticate_user!, :except => [:index, :show]
# GET /articles
# GET /articles.xml
def index
@articles = Article.published.page(params[:page]).per(5).ordered
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => @articles }
end
end
# GET /articles/1
# GET /articles/1.xml
def show
@article = Article.find(params[:id])
@comment = Comment.new(:article=>@article)
respond_to do |format|
format.html # show.html.erb
format.xml { render :xml => @article }
end
end
# GET /articles/new
# GET /articles/new.xml
def new
@article = Article.new
respond_to do |format|
format.html # new.html.erb
format.xml { render :xml => @article }
end
end
# GET /articles/1/edit
def edit
@article = Article.find(params[:id])
authorize! :edit, @article
end
# POST /articles
# POST /articles.xml
def create
authorize! :create, @article
@article = Article.new(params[:article])
@article.user_id = current_user.id
respond_to do |format|
if @article.save
format.html { redirect_to(@article, :notice => 'Article was successfully created.') }
format.xml { render :xml => @article, :status => :created, :location => @article }
else
format.html { render :action => "new" }
format.xml { render :xml => @article.errors, :status => :unprocessable_entity }
end
end
end
# PUT /articles/1
# PUT /articles/1.xml
def update
@article = Article.find(params[:id])
authorize! :update, @article
respond_to do |format|
if @article.update_attributes(params[:article])
format.html { redirect_to(@article, :notice => 'Article was successfully updated.') }
format.xml { head :ok }
else
format.html { render :action => "edit" }
format.xml { render :xml => @article.errors, :status => :unprocessable_entity }
end
end
end
# DELETE /articles/1
# DELETE /articles/1.xml
def destroy
@article = Article.find(params[:id])
authorize! :destroy, @article
@article.destroy
respond_to do |format|
format.html { redirect_to(articles_url) }
format.xml { head :ok }
end
end
end
文章模型：
class Article < ActiveRecord::Base
attr_accessible :body, :title, :tag_names
has_many :comments, :dependent => :destroy
has_many :taggings, :dependent => :destroy
has_many :tags, :through => :taggings
validates_presence_of :title, :body
validates_uniqueness_of :title
attr_writer :tag_names
after_save :assign_tags
validates_numericality_of :user_id
belongs_to :user
scope :published, lambda {{:conditions => ['published = ?', true]}}
scope :ordered, lambda {{:order => "Created_at DESC" }}
def tag_names
@tag_names || tags.map(&:name).join(' ')
end
private
def assign_tags
if @tag_names
self.tags = @tag_names.split(/\,/).map do |name|
Tag.find_or_create_by_name(name)
end
end
end
end
表单部分用于创建文章：
<%= form_for(@article) do |f| %>
<% if @article.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(@article.errors.count, "error") %> prohibited this article from being saved:</h2>
<ul>
<% @article.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :title %><br />
<%= f.text_field :title %>
</div>
<div class="field">
<%= f.label :body %><br />
<%= f.text_area :body %>
</div>
<div class="field">
<%= f.label :tag_names, "Tags" %>
<%= f.text_field :tag_names %>
</div>
<div class="field">
<%= check_box("article", "published" ) %>
<%= "Publish article" %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
非常感谢你能给我的任何帮助。
按要求：
Ability.rb
class Ability
include CanCan::Ability
def initialize(user)
user ||= User.new # guest user
if user.role? :Admin
can :manage, :all
can :publish, Article
elsif user.role? :Moderator
can :read, [Article, Comment]
can [:edit, :update], Comment
elsif user.role? :Member
can :read, :all
can :create, [Article, Comment]
can [:edit, :update], Comment
end
end
end
P.S。我能看到的唯一其他错误（我不知道它是否相关或完全不同）是在尝试查看文章（show.html.erb）时收到以下错误：
Processing by ArticlesController#show as HTML
Parameters: {"id"=>"1"}
Article Load (0.2ms) SELECT "articles".* FROM "articles" WHERE "articles"."id" = ? LIMIT 1 [["id", "1"]]
Completed 500 Internal Server Error in 44ms
ActiveModel::MassAssignmentSecurity::Error (Can't mass-assign protected attributes: article):
app/controllers/articles_controller.rb:18:in `new'
app/controllers/articles_controller.rb:18:in `show'
答案 0 :(得分：1)
我猜测authorize! :create, @article中的ArticleController.create行存在问题。在执行时，尚未创建@article。
根据CanCan来源，我认为以下可能会做你想要的：
def create
authorize! :create, Article
@article = Article.new(params[:article])
@article.user_id = current_user.id
...
答案 1 :(得分：0)
因为这个原因，没有创建这篇文章。
authorize! :create, @article
你必须向我们展示你的能力模型，能力.rb。
你可能也想尝试一下。 bundle install并重新启动服务器。