DirtyInformation

Single Responsibilty, How Did I Forget You

12 Apr 2011

Sometimes when developing I forget some of the basics as I go along. This time and many times in the past I have forgotten to follow the Single Responsibility Principle. I always forget it in the same place, the User object.

The User class always appears to be a place to take care of login and logout, but it does so much more. Everytime I need to change the User or expand to multiple types I end up dealing with login issues. It is easy to think that the responsibility of the User is to handle all things related to the User, but logins are not part of the User. The login is the responsibility of the Credentials.

What happens when I need multiple logins to act on behalf of the same user, or when I have multiple user types, but I want to use the same login system. In the past I’ve always created a User and an AdminUser, with separate logins. Why?…It just felt right, and the AdminUser had different properties than a regular user. Now I have multiple user types that should share some common code. Sweet, a module will do that for me. It still doesn’t solve all of my issues. I have to separate logins. What should I have done?

A Credential class should be created and can link to a profile. This allows my Credential class to only change if the login system changes. Each user type can be a separate Profile class. This eases the burden of the user class and allows greater future expandability.

Why didn’t I do this in the past? I’ve run into this problem many times, but never really got it. Now I’d just like to say, “I GET IT!!!”

The Past

• Testing Named Agents 03 Feb 2017
• Two Duplication Refactorings in Elixir 18 Jan 2017
• B is for BigDecimal 24 Sep 2014
• A is for Abbrev 02 Sep 2014
• Missed Chances 15 Aug 2014
• Style Guides are Failures 15 Jun 2014
• What is BDD anyway? 15 Apr 2014
• An Agile Contract 31 Mar 2014
• What Do I Want 23 Mar 2014
• Just the Tip 16 Mar 2014
• Important Partnerships 11 Mar 2014
• Lost in Translation 03 Mar 2014
• Story Splitting Revisited 23 Feb 2014
• Let your yes be yes and your no be no 16 Feb 2014
• Lethal Injection 09 Feb 2014
• Smaller is Better 02 Feb 2014
• A Second Time 26 Jan 2014
• Introspective 20 Jan 2014
• Self Reflection for the Win 06 Dec 2013
• Why? Why? Why? 30 Sep 2013
• A New Gig 18 Sep 2013
• Exceptional Comments 15 Jun 2013
• Role Objects in Acceptance Tests 30 Apr 2013
• Open Closed Ruby Woes 28 Apr 2013
• Write Something 12 Apr 2013
• A Great Cast of Characters 06 Mar 2012
• When is the Release Party? 19 Aug 2011
• Single Responsibilty, How Did I Forget You 12 Apr 2011
• Change Classes not Styles 05 Nov 2010
• My MongoDB Cookbook Recipe 20 Jul 2010
• Agile Says What? 05 Nov 2009
• Inject & Me - BFFs 07 Sep 2008