Question

This is driving me crazy… Here’s what I THINK I’m doing in the #show action of my users_controller.rb

1. I’m setting session[:zot] ONLY via the method “pass_session_data()”.
2. In that method, I pass the contents of “@foo” to the session[:zot].
3. Later in the #show action, I call amz_search(), and I replace some text in @nowreading.content with the a URL and that text.

After the calling the method “amz_search()” all bets are off. When I put “test 4”, I see the session[:zot] changed to include the URL that I added to @nowreading.content. Worse still, my variable @foo also changed when I changed @nowreading.content. WTF. I don’t understand how these two variables are linked!

What am I doing wrong? I want to pass the unaltered text (@foo before it changes to the version with the URL) to session[:zot].

In the show action of the Users controller, I have:

@user = User.find(params[:id])
@nowpost = Nowpost.new

@tweet_sample = Micropost.find(:all, :conditions => ["username = ?", "#{@user.twithandle}"])

@multi_streams = (@tweet_sample + @user.nowposts).sort_by(&:updated_at)
# takes all posts in the systems and order them by update-time

parse_the_streams(@multi_streams) 

pass_session_data() 

 puts "test 3"
 puts session[:zot]
 puts "this is @foo = #{@foo.content}"
 puts "Test C = #{@nowreading_raw.content}"   

amz_search(@reading_title, 'Books')

 puts "test 4"
 puts session[:zot]
 puts "this is @foo = #{@foo.content}"
 # @foo totally changed even though I only updated @nowpost.content
 # I don't understand how these two variables are linked!
 puts "Test D = #{@nowreading_raw.content}"   

 end #show action

Here are the methods call from the show action:

 def parse_the_streams(multi_streams)
     multi_streams.each do |tweet, i|  
 puts "i = #{i} // tweet = #{tweet.content}"
       if tweet.content.match(/#nowreading/).to_s == "#nowreading"    
         @nowreading_raw = tweet 
         @foo = tweet
         tweet.update_attributes(:cat_id => "1")

        if tweet.content.match(/#nowreading$/)
          @reading_title = tweet.content.match(/([^\s]*\s){5}(#nowreading$)/).to_s
        else
          @reading_title = tweet.content.match(/'(.+)'|"(.+)"/).to_s
        end              
     end
   end
 end

 def pass_session_data  
      @nowreading = @nowreading_raw
      puts "PASS SESSION DATA"
      puts "this is @foo = #{@foo.content}"
      puts "----------"
      reading = @foo

      content = {
      "reading"=>reading
      }

      session[:zot] = content
    end

  def amz_search(search, index)
        res = Amazon::Ecs.item_search(search, {:response_group => 'Images', :search_index => index})
        puts "Test 1 = #{session[:zot]["reading"].content}" 

        tempy = @nowreading.content.match(/#nowreading.*/).to_s.gsub("#nowreading",'') # strips away the #nowreading tag

        puts "Test 2 = #{session[:zot]["reading"].content} -- this is still OK"   
        puts "and FOO hasn't changed yet = #{@foo.content}"   

        url = create_amz_url(search, asin)["finished"]

        @nowreading.content = tempy.match(/#{search}.*/).to_s.gsub("#{search}", url)

        puts "WTF -- @foo changed -- WHY!?!? = #{@foo.content}"   
        puts "Test 4 = #{session[:zot]["reading"].content}"
  end

  def create_amz_url(text, asin)
     url = Hash.new
     url["raw"] = "http://www.amazon.com/dp/#{asin}/#{associate_code}"
     link = "http://www.amazon.com/dp/#{asin}/#{associate_code}"
     url["finished"] = "<a href=#{link} target=\"_blank\">#{text}</a>"
     return url
  end

Thank you for your help.

Answer 1

You should spend 30 minutes refactoring that code – eliminate as many instance variables as possible and use explicit arguments to your functions rather than operating on the instance variables.

I’m pretty sure your problem is that

@foo == @nowreading == @nowreading_raw
session[:zot] = {"reading" => @foo}

and then you change @nowreading right before your WTF statement.

tweet is an object, so when you say @foo=tweet; @nowreading=tweet, @foo and @nowreading point to the same object, and modifying either will modify both.