Rails网站上的UnknownAttributeError

Question

关于如何使用评论和标签创建Ruby-on-Rails博客网站tutorial之后，我已将我的工作放在https://github.com/khpeek/jumpstart-blogger/上。

问题在于，当我尝试使用如下所示的标签创建新文章时，

我在ArticlesController中创建了一条错误消息＆＃34; ActiveRecord :: UnknownAttributeError＃create＆＃34; （见下文）。

然而，根据教程，我应该在这一点上期望文章能够经历＆＃34;。 articles_controller.rb有一个＆＃39;设置＆＃39; tag_list的方法：

class ArticlesController < ApplicationController

  include ArticlesHelper
  def index
    @articles = Article.all
  end

  def show
    @article = Article.find(params[:id])
    @comment = Comment.new
    @comment.article_id = @article_id
  end

  def new
    @article = Article.new
  end

  def tag_list=(tags_string)
  end

  def create
    # fail
    @article = Article.new(article_params)
    @article.save
    flash.notice = "Article '#{@article.title}' created."
    redirect_to article_path(@article)
  end

  def destroy
    @article = Article.find(params[:id])
    @article.destroy
    flash.notice = "Artice '#{@article.title}' deleted."
    redirect_to articles_path
  end

  def edit
    @article = Article.find(params[:id])
  end

  def update
    @article = Article.find(params[:id])
    @article.update(article_params)
    flash.notice = "Article '#{@article.title}' updated."
    redirect_to article_path(@article)
  end

end

此外，＆＃34; to_s＆＃34; ＆＃34; Tag＆＃34;的方法class已被修改为返回其名称：

class Tag < ActiveRecord::Base
    has_many :taggings
    has_many :articles, through: :taggings

    def to_s
        name
    end
end

简而言之，我不明白为什么tag_list未被识别为Article的属性。我该如何解决这个问题？

Answer 1

在你article.rb添加：

def tag_list=(tags_string)
  # first split the tags based on "," which is coming from the form
  tag_names = tags_string.split(",").collect{|s| s.strip.downcase}.uniq
  # search if any particular tag is present or not, based on that assign them
  new_tags = tag_names.collect { |name| Tag.find_or_create_by(name: name) }
  self.tags = new_tags
end

此外，在 articlesController.rb 中添加：

def article_params
 params.require(:article).permit(:title, :body, :tag_list)
end

希望它有所帮助！

Answer 2

您似乎正在使用Rails 4.您是否已将tag_list包含在Strong参数许可列表中？