Ruby/Rails break out of nested method - ruby-on-rails

Question

I have a method1 which calls other methods depending on params and then returns a json. One of these methods checks if a specific user exists. If the user doesn't exist the method should render a JavaScript alert. At first I got an error that render was called multiple times (which was correct). So I tried adding break but received an invalid break error. So I tried return but then I still get the Render and/or redirect were called multiple times in this action. How can I break out of method1 when I'm in method2, so that only the render in method2 gets called?
def method1
data = case params["foobar"]
when "case1"
methodxy
...
else
method2
end
render json: data
end
def method2
if user.exists?
return {...}
else
render(
html: "<script>alert('Unknown user!')</script>".html_safe,
layout: 'application'
)
return
end
end

Answer 1

Technically you could achieve this with a throw ... catch, which is essentially acting like a GOTO statement. But I would not advise this; the code is already too messy, and you'd be making the problem worse.
Instead, you should aim to clean up the flow in method1. Make the logical flow and responses clearer. For example, maybe something like:
def method1
if !user.exists?
render(
html: "<script>alert('Unknown user!')</script>".html_safe,
layout: 'application'
)
else
data = case params["foobar"]
when "case1"
methodxy
...
else
method2
end
render json: data
end
end
def method2
# ...
end
You could then refactor this further, e.g. by moving the user.exists? check into a before_filter and moving that case statement into its own method, to simplify things.
The end result could look something along the lines of:
before_filter :ensure_user_exists, only: :method1
def method1
render json: foobar_data
end