Lenz book - Chapter 7 - Page 199... HELP.

[grenadier42]

I am getting an error... I am using Ruby 1.8.4, Rails 2.1.0.

-----

NoMethodError in Story#show

Showing story/show.rhtml where line #1 raised:

You have a nil object when you didn't expect it!
The error occurred while evaluating nil.name

Extracted source (around line #1):

1: <h2><&#37;= @story.name %></h2>
2: <p><%= link_to @story.link, @story.link %></p>

-----

I have ensured that the permalinks exist... It's driving me NUTS.

Code below...

Story_controller.rb

                
                
class StoryController < ApplicationController
  skip_before_filter :verify_authenticity_token
 
  def show
    @story = Story.find_by_permalink(params[:permalink])
  end 
  def index
    @story = Story.find(:first, :order => 'RAND()')
  end
  def new
    @story = Story.new(params[:story])
    if request.post? and @story.save
      flash[:notice] = 'Story submitted!'
      redirect_to :action => 'index'
    end
  end
end

I have checked this over and over... If someone could help, please do.

EDIT:

Okay, I even resorted to copying and pasting from the code archive. I AM FULL OF FAIL. Bleh. It didn't work. Perhaps the problem is with Rails 2.1.0. ???

EDIT 2:

What... The... F --

It works now... ? I just had to restart WEBrick.

...

Whatever, eh? Mods, delete this thread whenever... Sorry.

[Delameko]

When you say Lenz book, do you mean the first one, Build Your Own Ruby on Rails Web Applications, and not Simply Rails 2?

I don't have a copy of the first book so I can't say exactly what the problem is, Rails 2.1 is quite different from Rails 1.2 (which I assume is what the first book uses), so that could be the problem but it also might not.

The error you are getting is because find is not finding a record. Do you have a permalink column in your table? Do all the stories in your database have permalinks attached? I notice that your index pulls in the only one random record, it's possible it pulls in one that doesn't have a permalink.

[diederikvanliere]

I have got the exact same problem...
I have checked everything I think including spelling, the tests run fine.
I am using Ruby 2.1 and I have got the "Build Your Own Ruby on Rails Web Applications book.

this is the code from the controller:

class StoryController < ApplicationController
def index
@story = Story.findfirst, rder => 'RAND()')
end

def new
@story = Story.new(params[:story])
if request.post? and @story.save
flash[:notice] = 'Story submission succeeded'
redirect_to :action => 'index'
end
end

def show
@story = Story.find_by_permalink(params[ermalink])
end

end

and this is the code from the view

<h2><%= @story.name %></h2>
<p><%= link_to @story.link, @story.link %></p>


Hopefully, someone can help me...
thanks a lot!
best,
Diederik

[diederikvanliere]

I have got the exact same problem...
I have checked everything I think including spelling, the tests run fine.
I am using Ruby 2.1 and I have got the "Build Your Own Ruby on Rails Web Applications book.

this is the code from the controller:

class StoryController < ApplicationController
  def index
    @story = Story.find(:first, :order => 'RAND()')
  end
 
  def new
    @story = Story.new(params[:story])
	if request.post? and @story.save
	  flash[:notice] = 'Story submission succeeded'
	  redirect_to :action => 'index'
	end
  end
 
  def show
    @story = Story.find_by_permalink(params[:permalink])
  end 
 
end

and this is the code from the view

<h2><%= @story.name %></h2>
<p><%= link_to @story.link, @story.link %></p>

Hopefully, someone can help me...
thanks a lot!
best,
Diederik

[MrCarrot]

Like Delameko says: do all of your records definitely have something in their permalink fields?

[diederikvanliere]

When I go to IRB mode then the story.find_by_permalink function does work.....so I am positive that all fields have a permalink value (I also checked this in the mysql tables)

[Delameko]

What about the name field? It's trying to display @story.name on the view page, if the name isn't there then it will also throw this error.

[diederikvanliere]

The exact error message is:

You have a nil object when you didn't expect it!
The error occurred while evaluating nil.name

If I go to the Ruby console and enter:
s = Story.find_by_name('foo')
then it will find story 'foo'

It is really driving me nuts but thanks for your questions, hopefully you have some more suggestions on how to fix this!
best,
Diederik

[Delameko]

If I go to the Ruby console and enter:
s = Story.find_by_name('foo')
then it will find story 'foo'

Having typed that into the console, now type:

s.name

What do you get?

[diederikvanliere]

When I enter s.name then I get
=> foo

so that seems to work......

[Delameko]

Sorry, I misread. Try this instead:

s = Story.find_by_name('foo')
s.permalink

[diederikvanliere]

if I enter s.permalink it returns 'foo' but that's because the permalink is also called foo, so the permalink variable does exist and does have an appropriate value......

[Delameko]

Does it work if you do:

  def show
    @story = Story.find_by_permalink('foo')
  end

At the end of the day, ActiveRecord isn't finding your foo permalink, so something's wrong somewhere. It's hard to debug without seeing everything.

Is permalink even being passed to the show action? When you get this error:

You have a nil object when you didn't expect it!
The error occurred while evaluating nil.name

Look further down the page and you'll see a list of parameters that are being passed. Make sure there's one that says ermalink => 'foo'.

If it's not being passed at all, have you set to_param in your model.

# in story.rb
def to_param
  permalink
end

[diederikvanliere]

I think I found the error:
it says {"id"=>"foo"} instead of {"permalink" => "foo"} so somewhere the permalink, maybe in the route.rb file? has not been set up correctly. do you know how to fix this? You are really helpful!!! thanks a lot!
best,
Diederik

[Delameko]

OK, I've just realised the error, change your controller to:

@story = Story.find_by_permalink(params[:id])

[brownmapleleaf]

Your code is not Rails 2.1. If you try to use old ruby rails code with 2.1, it simply won't work.

Here are the solutions to make your code work with rails 2.1.

stories_controller.rb
class StoriesController < ApplicationController
  def index
	@story = Story.find(:first, :order => 'RANDOM()')
  end
  def new
	@story = Story.new
  end
  def create
 	@story = Story.new(params[:story])
	if @story.save
	flash[:notice] = 'Story submission succeeded'
	redirect_to stories_path
	else
	render :action => 'new'
	end
  end
  def show
	@story = Story.find(params[:id])
  end
end

<h2>
  <%= @story.name %>
</h2>
<p>
  <%= link_to @story.link, @story.link %>
</p>

This is the show.html.erb

I highly reccommend you get the Simply Rails 2 book. It covers the new ruby rails version.

[diederikvanliere]

Dear Delameko,

Thank you soo much!!!!! That is indeed the answer, it works now fine. Apparently I had become blinded by my own code and my newbie status to Ruby. Again, thanks so much, you have been really helpful!
best,
Diederik