How can I access a different object collection in a view in Rails?

Question

I'm not sure how to search for this answer, so I'll go ahead and ask it.

In my rails project I have a User model and a foo model. A user can have one or more foo models assigned to it. I have accomplished this by adding

has_many :foo, :through => :user_foo

in my user model.

Now, over in my view, I want to display a list of all foos. Not just the ones that are selected (i will be making these radio buttons, but that's another question). When I try to do this (yes, i'm using haml):

    - for foo in @foos

I get this error:

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.each

My assumption is that this is caused because the @foos collection is empty. What is the proper way to get access to this collection within my user view?

** edit **

I think my initial question was a bit confusing. the first issue i'm trying to figure out is how to access a collection of foos from within my user view. the relationship doesn't matter. I just want a list of all foos in the system. not just the ones assigned to the user.

Answer 1

I assume that you have belongs_to :user in your Foo class?

What does your controller code look like? To show all foos it should have something like this:

def index
  @foos = Foo.all
end

Answer 2

The error suggests you foo object is empty.

If you want all Foo's connected with the current user object, you use

my_user = User.find(1) # finds user with id no. 1
list_of_foos = my_user.foos # finds all foos associated with my_user

should work

If you are looking for all foo's, no matter what their association, you use

list_of_foos = Foo.find(:all)

This might not be up to the Rails syntax that's currently in fashion: it's been a while since I actively did Rails development, but this if I understand the question right, this should help you. Good luck.

Answer 3

To access all Foos just use

@foos = Foo.all

in your controller.

The error you were experiencing before, the nil object error could be prevented by a check like:

- if @foos.empty?
  %p There are no Foos
- else
  ...

Also, the best way to iterate over a collection is by using the #each method, not a for loop. For example:

- @foos.each do |foo|
  %p= foo.name

So a finished example would be:

- if @foos.empty?
  %p There are no Foos
- else
  - @foos.each do |foo|
    %p= foo.name