从帮助程序退出 Ruby On Rails 控制器方法

Question

Let's imagine I have a class

class Test < ActiveRecord::Base
  include AuthenticatorHelper

  def test
    authenticate_or_fail!
    puts "If I fail, this should be unreachable"
  end
end

and

module AuthenticationHelper
  def authenticate_or_fail!
    @user = User.find(params[:token])
    unless @user
      render :json => {code: 401, :err => 'Unauthorized'} and return
    end
  end
end

What I want to do is either authenticate or reply with a json msg. However, it will obviously ignore my return statement due to nesting and it will always print my message

If I fail, this should be unreachable

Answer 1

Regarding the question

You could extract the call into a before_filter / before_action (based on the rails version).

class Test < ActiveRecord::Base
  include AuthenticatorHelper

  before_action :authenticate_or_fail!

  def test
    puts "If I fail, this should be unreachable"
  end
end

Please see the documentation for further details.

Because your helper method renders in case of a failure, rails will prevent the test method to be called. You will not need the and return part then, which would only have returned from the method anyway and as such was a NoOp.

Apart from the question but also noteworthy:

I don't want to point out errors for the sake of it. I just want to prevent the OP from running into a series of bugs later on.

 User.find(params[:token])

Will raise an exception if no record is found. Because of that, the unless @user part will not be evaluated in case of an invalid token. You could use

User.find_by(id: params[:token]) 

instead.

Your class which looks like it acts as a controller is named Test and inherits from ActiveRecord::Base . The first is unusual as TestsController would be more along the lines of rails and the seconds looks plain wrong. A controller has to inherit from ApplicationController (which itself inherits from ActionController::Base )