Question

I have a small encyclopedia of articles with my Article.rb:

class Article < ActiveRecord::Base
  attr_accessible :name, :content
end

I now want to automatically link within the articles if I find text in one article that corrisponds to the name of another article. E.g. in the article named “Example One” the content is “You can also check Example Two for further reading.” On save of “Example One” I want to set a link to the article “Example Two”. My approach is to add to Article.rb

class Article < ActiveRecord::Base
  attr_accessible :name, :content

  before_save :createlinks

  def createlinks
    @allarticles = Article.all
    @allarticles.each do |article|
      self.content = changelinks(self.content)
    end
  end

  def changelinks(content)
    content = content.gsub(/#{article.name}/, "<%= link_to '#{article.name}', article_path(article) %>")
  end

My articles_controller is:

def update
  @article = Article.find(params[:id])
  if @article.update_attributes(params[:article])
    redirect_to admin_path
  else
    render 'edit'
  end
end

But obviously there is an error refering to the line content = content.gsub(etc…):

NameError in ArticlesController#update
undefined local variable or method `article’ for #

How can I fix this so that it checks all other article names and creates the links for the current article I want to save?

Answer 1

Your changelink method does not “know” what is the article variable. You have to pass it as an argument:

  def createlinks
    @allarticles = Article.all
    @allarticles.each do |article|
      self.content = changelinks(self.content, article)
    end
  end

  def changelinks(content, article)
    content = content.gsub(/#{article.name}/, "<%= link_to '#{article.name}', article_path(article) %>")
  end

But this way to implement links instead of the Articles’ name is not the best in my opinion.