Ruby on Rails中的未定义方法

Question

I am new to Ruby on Rails and im stuck on something so simple but I just cant figure it out.

I scaffolded a Video model, controller and view and then created a Welcome controller for the home page.

I manually created an index.html.erb file in the welcome view folder and proceeded to route the home page to Welcome#index. All working fine for now.

Thing is when I define a method in the welcome_controller like this

def foo
   puts 'Hello'
end

and I call it in the welcome/index.html file like this

<%= foo %>

I get the following error: undefined local variable or method `foo' for #<#:0x39675d8>

Answer 1

Controller actions aren't view helpers, you'll want to put foo in either application_helper.rb or welcome_helper.rb to use it like you are and change it to remove the puts , like this:

def foo
  'Hello'
end

This will insert Hello into your view (which is what I think you were expecting)

Based on your comments below, you should probably be using a scope in your model...

scope :highlighted -> { (where(highlight: true) }

... to return highlighted records from your controller...

@highlighted = Videos.highlighted

... and then iterate over @highlighted in your view...

<% @highlighted.each do |video| %>
<%= ...do something with video here... %>
<% end %>

please read more about all this here:

http://guides.rubyonrails.org/index.html

and specificially for scopes here...

http://guides.rubyonrails.org/active_record_querying.html

Answer 2

You can't call arbitrary "things" in the controller.

What's exposed in the controller are its instance variables, eg, @foo .

If you really want to call a method that uses puts , put it in a helper, eg, welcome_helper.rb (or whatever the convention would be).

Note, however, that this won't do what you appear to believe it will, namely, put a "Hello" on the web page. You're basically writing directly to the console, not even the log file.

What specifically are you trying to accomplish?