ruby-on-rails - Rails 网站上的 UnknownAttributeError

Question

我正在关注 tutorial关于如何创建带有评论和标签的 Ruby-on-Rails 博客网站，目前为止我的工作已放在 https://github.com/khpeek/jumpstart-blogger/ 上.

问题是，当我尝试使用如下所示的标签创建一篇新文章时，

我收到错误消息“ArticlesController#create 中的 ActiveRecord::UnknownAttributeError”(见下文)。

但是，根据教程，此时我应该期望文章“通过”。 articles_controller.rb 有一个用于 tag_list 的“设置”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，“Tag”类的“to_s”方法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 没有被识别为 Article 的属性。我该如何解决这个问题？

Answer 1

在你的article.rb中添加:

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

希望对您有所帮助!