Why Rails Controller Action Method Requires Parameter

Question

It's a brand new project. Here's the exact commands I've run:

1. rails new MyProject
2. bundle install
3. rails generate controller Image

I've added this one route:

1. root :to => "image#process"

I've added this function to the ImageController (image_controller.rb)

def process
  render :nothing => true
end

And finally I've removed the default index.html. When I run the project, it has an error saying process expects 0 parameters, not 1. So I modify the method to tell me what parameter is trying to be sent to process.

def process(arg)
  p arg
  render :nothing => true
end

The string "process" is printed to the screen. I've done several Rails projects before and never encountered this. Did I miss a step somewhere? Is this something new in Rails 3.0.10? Or maybe caused by Ruby 1.9.2? I think I usually use 1.8.7.

Answer 1

You can not name an action as process, this is an internal method for rails controllers, name it something else.

There's a bunch of other names you can't use for controller actions like render, params, request. Unfortunately there isn't a list of these things.

Answer 2

For future reference, in case you aren't using it, you can view all internal methods and classes here: ruby doc with nav on top right

Helps me when picking names.