Question

我已经成功实现了新的艺术家作品的添加，这些作品未包含在Ryan Bates的轨道广播中＃258 http://railscasts.com/episodes/258-token-fields

换句话说，用户可以输入一个艺术家名称，该名称将使用jquery tokinput自动完成。但是，我希望自动填充结果只显示由该个人用户创建的艺术家名称。

这有意义吗？一个更好，更容易理解的例子是collection.rb，其中用户创建帖子并为帖子指定一个“集合”，但他们应该只能将帖子添加到他们自己创建的集合中。

这是使用artist_tokens作为虚拟属性的帖子表单：

<%= form_for @post, :validate => true, :html => {:multipart => true} do |f| %>
  <%= render 'shared/error_messages', :object => f.object %>
    <div class="field">
      <%= f.label :title, 'Title:' %><br /> 
      <%= f.text_field :title %><br />

      <%= f.label :artist_tokens, "Artists" %><br />
      <%= f.text_field :artist_tokens, "data-pre" => 
       @post.artists.map(&:attributes).to_json %>

    </div>
  <div class="actions">
    <%= f.submit "Submit" %>
  </div>
<% end %>

通过在帖子表单上输入artist_tokens字段的值找到艺术家，我还添加了“添加{params [：q]}”选项以添加新条目。

class ArtistsController < ApplicationController

  def index
    @artists = Artist.where("name like ?", "%#{params[:q]}%")
    results = @artists.map(&:attributes)
    results << {:name => "Add: #{params[:q]}", :id => "CREATE_#{params[:q]}_END"}

    respond_to do |format|
      format.html
      format.json { render :json => results }
    end
  end

我添加了额外的代码来解析id的'new'条目，然后用它们创建一个新的艺术家。然后再次分配artist_ids。

post.rb
 def artist_tokens=(ids)
    ids.gsub!(/CREATE_(.+?)_END/) do
      Artist.create!(:name => $1).id
    end
    self.artist_ids = ids.split(",")
  end

除了仅通过current_user的条目缩小json结果的能力之外，一切都很有效。我该怎么做呢？我是否需要在表中存储条目创建者的user_id？我怎么能这样做？

编辑：模型的关联

# app/models/user.rb

class User < ActiveRecord::Base
  has_many :posts
  has_many :artists, :through => :posts

end



# app/models/post.rb

class Post < ActiveRecord::Base

  belongs_to :user
  has_many :artisanships
  has_many :artists, :through => :artisanships

end

# all/models/artist.rb

class Artist < ActiveRecord::Base

  has_many :artisanships
  has_many :users, :through => :artisanships
  has_many :posts, :through => :artisanships

end


# app/models/artisanship.rb

class Artisanships < ActiveRecord::Base

  belongs_to :post
  belongs_to :artist
  has_one :user, :through => :post

end

编辑：posts_controller.rb

class PostsController < ApplicationController

  before_filter :authenticate_user!, :only => [:create, :edit, :update, :destroy]
  before_filter :authorized_user, :only => [:destroy, :edit, :update]

  def create
    @user = current_user
    @post = current_user.posts.build(params[:post])
    if @post.save
      flash[:success] = "Post created!"
      redirect_to root_path
    else
       @feed_items = current_user.feed.paginate(:per_page => "10", :page => params[:page])
      render 'pages/home'
    end
  end

  def index
    @posts = Post.paginate(:page => params[:page])
  end

  def show
    @post = Post.find(params[:id])
  end

  def edit
    @post = Post.find(params[:id])
  end

  def update
      @post = Post.find(params[:id])
      respond_to do |format|
        if @post.update_attributes(params[:post])
          format.html { redirect_to(post_path(@post), :notice => 'Post was successfully updated.') }
        else
          format.html { render :action => "edit" }  
        end
      end
    end

  def destroy
    @post.destroy
    redirect_to root_path
  end

  def likers
     @title = "Likers"
     @post = Post.find(params[:id])
     @likers = @post.likers.paginate(:page => params[:page])
     render 'show_likers' 
   end

   def search
     if params[:q]
       query = params[:q]
       @search = Post.search do
         keywords query
       end
       @posts = @search.results
     end
   end


private
  def authorized_user
    @post = Post.find(params[:id])
    redirect_to root_path unless current_user?(@post.user)
  end

编辑：尝试alias_method_chain首先设置post的user_id属性。（没有修复NULL db条目）参考：Rails 3: alias_method_chain still used?

 def attributes_with_user_id_first=(attributes = {})
    # Make sure not to accidentally blank out the important_attribute when none is passed in
    if attributes.include?(:user_id)
      self.user_id = attributes.delete(:user_id)
    end

    self.attributes_without_user_id_first = attributes
  end
  alias_method_chain :attributes=, :user_id_first

Answer 1

如果您不想修改模型中的任何内容，则可以这样做：

def index
  @artists = current_user.posts.join("artisianships").join("artists").
               where("artisianships.post_id = posts.id").
               where("artists.name like ?", "#{params[:q]}").
               select("artists.name as name, artists.id as id")
  results = @artists.map(&:attributes)
  results << {:name => "Add: #{params[:q]}", :id => "CREATE_#{params[:q]}_END"}

  respond_to do |format|
    format.html
    format.json { render :json => results }
  end
end

请注意，这里有很多连接，所以不推荐。

要调试Artist.create!(:name => $1, :user_id => self.user_id)无效的原因，如果我们能够看到更多代码，特别是action来创建Post

，那就太棒了

更新：您是否尝试将PostController#create更改为以下内容，但我觉得有效的代码应该可以正常工作，

@post = current_user.posts.build
if @post.update_attributes(params[:post])
   # do something
else
   # do something else
end

我不是专业人士而且不理解alias_method_chain因此无法评论为什么它不起作用。

Answer 2

如果您正在使用某些身份验证解决方案，例如设计，清除或authlogic，您可能已经拥有current_user方法。因此，在Artist模型中添加一列user_id：integer并执行以下操作：

#User model
has_many :artists

#Artist model
belongs_to :user

#Artists controller
def index
    @artists = current_user.artists.where("name like ?", "%#{params[:q]}%") #this answers your question!
    ... blah blah
end

当然，不要忘记在创建艺术家时设置user_id列。

Rails：使用jquery tokeninput（railscast＃258）创建新条目

2 个答案: