我创建了一个post_category表来为特定帖子添加一个类别。
例如，我创建了post_categories作为国家，像日本或中国。我想创建来自日本或中国等国家的文化或模式的帖子。我只专注于post_categories，因为现在和以下的国家是我所做的代码。
我创建了这个PostCategory，这里是迁移和模型
create_table "post_categories", force: :cascade do |t|
t.string "name"
t.string "description"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
class PostCategory < ActiveRecord::Base
has_many :posts, dependent: :destroy
NAMES = ["Japon", "Chine", "Corée du Sud", "Moyen Orient", "Indien"]
validates :name, inclusion: { in: PostCategory::NAMES, allow_nil: false }
end
我使用Post外键创建了PostCategory，这里是迁移和模型
create_table "posts", force: :cascade do |t|
t.string "cover"
t.string "subtitle"
t.string "title"
t.text "introduction"
t.text "body"
t.text "conclusion"
t.string "tag"
t.string "source"
t.string "link"
t.integer "user_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "post_category_id"
end
class Post < ActiveRecord::Base
belongs_to :user
belongs_to :post_category, dependent: :destroy
TAGS = ["Design", "Mode", "Tendance", "Life-Style", "Tradition", "Gastronomie", "Insolite", "Technologie"]
validates :tag, inclusion: { in: Post::TAGS, allow_nil: false }
mount_uploader :cover, ImageUploader
end
我想用简单的表单集创建一个类别，我希望我会在post show#view上显示
以下是post_categories controller
class PostCategoriesController < ApplicationController
# before_action :set_post_category, only: [:show, :new, :create, :destroy]
def show
@post_category = PostCategory.find(params[:id])
end
def index
@post_categories = PostCategory.all
end
def create
@post_category = post_categories.new(post_category_params)
if @post_category.save
redirect_to @post
else
render 'post_categories/show'
end
end
def new
@post_category = PostCategory.new
end
def edit
end
def update
end
def destroy
@post_category = PostCategory.find(params[:id])
@post_category.destroy
redirect_to post_path(@post)
end
private
# def set_post
# @post = Post.find(params[:post_id])
# end
def find_post_category
@post_category = PostCategory.find(params[:id])
end
def post_category_params
params.require(:post_category).permit(:name, :description)
end
end
这是posts controller
class PostsController < ApplicationController
before_filter :authenticate_user!, except: [:index, :show]
before_action :find_post, only: [:show, :edit, :update, :destroy]
def index
@posts = Post.all
end
def show
# @alert_message = "Vous lisez #{@post.title}"
end
def new
# if current_user and current_user.admin?
@post = Post.new
# else
# redirect_to posts_path
# end
end
def create
# if current_user and current_user.admin?
@post = @post_category.posts.new(post_params)
#@post = current_user.posts.new(post_params)
if @post.save
redirect_to @post
else
render :new
end
# else
# render 'shared/404.html.erb'
# end
end
def edit
end
def update
if @post.update(post_params)
redirect_to @post
else
render :edit
end
end
def destroy
@post.destroy
redirect_to :back
end
private
# def find_post
# @post = Post.find(params[:id])
# end
def set_post_category
@post_category = PostCategory.find(params[:post_category_id])
end
def post_params
params.require(:post).permit(:title, :subtitle, :introduction, :body, :cover, :tag, :post_category_id)
end
end
我不知道我可以创建哪些观点以及如何调用post new#view，因为我已经配置了这样的路线，我需要post_category_id。
resources :post_categories do
resources :posts
end
我必须在path
post_category_posts GET /post_categories/:post_category_id/posts(.:format) posts#index
POST /post_categories/:post_category_id/posts(.:format) posts#create
new_post_category_post GET /post_categories/:post_category_id/posts/new(.:format) posts#new
edit_post_category_post GET /post_categories/:post_category_id/posts/:id/edit(.:format) posts#edit
post_category_post GET /post_categories/:post_category_id/posts/:id(.:format) posts#show
PATCH /post_categories/:post_category_id/posts/:id(.:format) posts#update
PUT /post_categories/:post_category_id/posts/:id(.:format) posts#update
DELETE /post_categories/:post_category_id/posts/:id(.:format) posts#destroy
post_categories GET /post_categories(.:format) post_categories#index
POST /post_categories(.:format) post_categories#create
new_post_category GET /post_categories/new(.:format) post_categories#new
edit_post_category GET /post_categories/:id/edit(.:format) post_categories#edit
post_category GET /post_categories/:id(.:format) post_categories#show
PATCH /post_categories/:id(.:format) post_categories#update
PUT /post_categories/:id(.:format) post_categories#update
DELETE /post_categories/:id(.:format) post_categories#destroy
我想在show＃view post上添加该类别，并创建一个多帐户访问权限，以查找添加到特定类别的帖子。谢谢你的帮助
答案 0 :(得分：0)
你设置关系的方式因为有一个很大的缺陷 - 一个帖子只能属于一个类别，因为id存储在posts表中。
相反，你通常会使用多对多的关系：
class Post < ActiveRecord::Base
has_many :categories, :categories
has_many :post_categories
end
class Category < ActiveRecord::Base
has_many :posts
has_many :posts, through: :categories
end
class Categorization < ActiveRecord::Base
belongs_to :post
belongs_to :category
validates_uniqueness_of :category_id, scope: :post_id
end
此处categorizations表充当链接Post和Category的联接表 - 帖子可以包含任意数量的类别，反之亦然。
增加：
要创建连接模型和迁移到创建表，您可以执行以下操作：
rails g model Categorization post:belongs_to category:belongs_to
默认情况下，在生成器中使用属于为post_id和category_id创建外键。
您可能还希望在迁移中添加复合唯一性约束。
def change
# ...
add_index(:categorizations, [:post_id, :category_id], unique: true)
end
您使用CategoriesController在正确的轨道上，但我不会使用嵌套路线来创建帖子。相反，您可能只想使用普通的旧rails控制器，让用户通过复选框选择类别：
<%= form_for(@post) do |f| %>
<%= f.collection_check_boxes :category_ids, Category.all, :id, : name %>
<% end %>
然后，您可以将category_ids参数添加到白名单中：
def post_params
params.require(:post)
.permit(:title, :subtitle, :introduction,
:body, :cover, :tag, category_ids: []
)
end
奇怪的category_ids: []语法是因为我们想要允许一组标量值。
按ID查询某个类别的帖子可以这样完成：
Post.joins(:categories).where(category: 1)
您甚至可以通过传递数组来选择多个类别：
Post.joins(:categories).where(category: [1, 2, 3])
要从视图中将它连接在一起，您可以使用链接（对于单个类别）或表单（是表格可用于GET）以及复选框或选择。
处理文本输入有点棘手。一个天真的实现将是：
Post.joins(:categories).where(category: { name: params[:search_query] })
然而，用户输入必须完全匹配。有几个宝石为活动记录提供搜索功能。但是我会等待这个功能，直到你有更多的经验，因为它可能很难实现。
请参阅：