將標籤與條目關聯的問題

Question

這個問題的基本前提是如何使標籤鏈接工作，所以當你點擊它時，它會出現與此相關的所有條目。

但是，當您點擊鏈接時，基本上，儘管它的標題，空白頁顯示出來。它不顯示與其標籤相關聯的條目。

那麼顯然協會不在某個地方工作？或標籤控制器中的show方法不正確？不確定到底要修復什麼。

這是到目前爲止我的代碼（即屬於空白頁的部分是在最底層）

條目控制器

class EntriesController < ApplicationController 
    def index 
    @entries = Entry.all 
    @tags = Tag.all 
    end 

    def scrape 
    RedditScrapper.scrape 

    respond_to do |format| 
     format.html { redirect_to entries_url, notice: 'Entries were successfully scraped.' } 
     format.json { entriesArray.to_json } 
    end 
    end 
end 

標籤控制器

class TagsController < ApplicationController 
    def index 
    @tags = Tag.all 
    end 

    def show 
    @tag = Tag.find(params[:id]) 
    end 
end 

Entry Model

class Entry < ApplicationRecord 
    has_many :taggings 
    has_many :tags, through: :taggings 

    validates :title, presence: true 
    validates :link, presence: true 

    def tag_list 
    tags.join(", ") 
    end 

    def tag_list=(tags_string) 
    tag_names = tags_string.split(",").collect{|s| s.strip.downcase}.uniq 
    new_or_found_tags = tag_names.collect { |name| Tag.find_or_create_by(name: name) } 
    self.tags = new_or_found_tags 
    end 
end 

標籤型號

class Tag < ApplicationRecord 
    has_many :taggings 
    has_many :entries, through: :taggings 

    validates :name, presence: true 
end 

標註模型

class Tagging < ApplicationRecord 
    belongs_to :tag 
    belongs_to :entry 
end 

項index.html.erb

<div class="container-fluid"> 
    <div class="row"> 
    <div class="col-md-8"> 
     <div class="card-columns"> 
     <% @entries.reverse.each do |entry| %> 
      <div class="card"> 
      <div class="card-block"> 
       <p class="card-title"><b><%= entry.title %></b></p> 
       <p class="card-text"><%= entry.link %></p> 
      </div> 
      </div> 
     <% end %> 
    </div> 
    </div> 

    <div class="col-md-4"> 
    <p>Tags: <% @tags.each do |tag| %> 
     <%= link_to tag.name, tag_path(tag) %> 
    <% end %> 
    </div> 
</div> 

標籤show.html.erb（這是這部分不工作 - 即與標籤相關的條目 - 頁面顯示爲空白）

<h1>Entries Tagged with <%= @tag.name %></h1> 

<ul> 
    <% @tag.entries.each do |entry| %> 
    <li><%= link_to entry.title, entry_path(entry) %></li> 
    <% end %> 
</ul> 

<%= link_to "All Tags", tags_path %> 

Rails的控制檯

e = Entry.first 
    Entry Load (28.8ms) SELECT "entries".* FROM "entries" ORDER BY "entries"."id" ASC LIMIT $1 [["LIMIT", 1]] 
=> #<Entry id: 4, title: "Sweet old man at the beach: \"Would you like me to ...", link: "/r/funny/comments/5zut3e/sweet_old_man_at_the_beac...", created_at: "2017-03-17 08:20:25", updated_at: "2017-03-17 08:20:25"> 
irb(main):036:0> t = Tag.first 
    Tag Load (0.5ms) SELECT "tags".* FROM "tags" ORDER BY "tags"."id" ASC LIMIT $1 [["LIMIT", 1]] 
=> #<Tag id: 3, name: "https://www.reddit.com/r/funny/", created_at: "2017-03-17 08:20:26", updated_at: "2017-03-17 08:20:26"> 
irb(main):037:0> tag.entries 
NoMethodError: undefined method `entries' for nil:NilClass 

的Rails控制檯2

irb(main):041:0> tag = Tag.first 
    Tag Load (2.6ms) SELECT "tags".* FROM "tags" ORDER BY "tags"."id" ASC LIMIT $1 [["LIMIT", 1]] 
=> #<Tag id: 3, name: "https://www.reddit.com/r/funny/", created_at: "2017-03-17 08:20:26", updated_at: "2017-03-17 08:20:26"> 
irb(main):042:0> tag.entries << Entry.first 
    Entry Load (0.8ms) SELECT "entries".* FROM "entries" ORDER BY "entries"."id" ASC LIMIT $1 [["LIMIT", 1]] 
    (32.6ms) SAVEPOINT active_record_1 
    SQL (318.8ms) INSERT INTO "taggings" ("tag_id", "entry_id", "created_at", "updated_at") VALUES ($1, $2, $3, $4) RETURNING "id" [["tag_id", 3], ["entry_id", 4], ["created_at", 2017-03-18 05:05:24 UTC], ["updated_at", 2017-03-18 05:05:24 UTC]] 
    (0.3ms) RELEASE SAVEPOINT active_record_1 
    Entry Load (1.3ms) SELECT "entries".* FROM "entries" INNER JOIN "taggings" ON "entries"."id" = "taggings"."entry_id" WHERE "taggings"."tag_id" = $1 [["tag_id", 3]] 
=> #<ActiveRecord::Associations::CollectionProxy [#<Entry id: 4, title: "Sweet old man at the beach: \"Would you like me to ...", link: "/r/funny/comments/5zut3e/sweet_old_man_at_the_beac...", created_at: "2017-03-17 08:20:25", updated_at: "2017-03-17 08:20:25">]> 
irb(main):043:0> tag.save 
    (0.4ms) SAVEPOINT active_record_1 
    (0.3ms) RELEASE SAVEPOINT active_record_1 
=> true 
irb(main):044:0> Tag.first.entries 
    Tag Load (0.8ms) SELECT "tags".* FROM "tags" ORDER BY "tags"."id" ASC LIMIT $1 [["LIMIT", 1]] 
    Entry Load (1.1ms) SELECT "entries".* FROM "entries" INNER JOIN "taggings" ON "entries"."id" = "taggings"."entry_id" WHERE "taggings"."tag_id" = $1 [["tag_id", 3]] 
=> #<ActiveRecord::Associations::CollectionProxy [#<Entry id: 4, title: "Sweet old man at the beach: \"Would you like me to ...", link: "/r/funny/comments/5zut3e/sweet_old_man_at_the_beac...", created_at: "2017-03-17 08:20:25", updated_at: "2017-03-17 08:20:25">]> 
irb(main):045:0> 

個

導軌刮碼

需要 '開URI'

模塊RedditScrapper

高清自我。刮 DOC =引入nokogiri :: HTML（開放（ 「https://www.reddit.com/」））

entries = doc.css('.entry') 
entries.each do |entry| 
    title = entry.css('p.title > a').text 
    link = entry.css('p.title > a')[0]['href'] 
    name = entry.css('p.tagline > a.subreddit')[0]['href'] 
    Entry.create!(title: title, link: link) 
    Tag.create!(name: name) 

end 

末

末

Answer 1

更改刮刀代碼來構建的關聯。

而不是...

Entry.create!(title: title, link: link) 
    Tag.create!(name: name) 

做...

entry = Entry.create!(title: title, link: link) 
    tag = Tag.create!(name: name) 
    tag.entries << entry 
    tag.save!