Sunday, June 23, 2013

Using Mvc 4 Display Modes for Feature Toggles

It occurred to me that it's possible to use the new Mvc 4 feature Display Mode (meant for switching views for mobile versions) as a complement for Feature Toggles.

Obviously this can only switch out an entire view (or partial view) but it can be a nice alternative to putting lots of @if(featureEnabled) {} tags through your view.

Add the following code to your global.asax Application_Start (or create an App_Start module).

 DisplayModeProvider.Instance.Modes.Insert(0, new DefaultDisplayMode("{NameOfFeature}")
     ContextCondition = (context => {true/false logic})

Then create 2 views - one for the feature being disabled and one for it being enabled - eg Index.cshtml and Index.{NameOfFeature}.cshtml.

This could also be used for similar concepts like permissions and a/b testing.

Thursday, June 20, 2013

Tfs Extensibility - Automatically Create Code Reviews on Checkin

I created a small plugin that has a percentage chance to create code review requests on checkin. You could enhance this pretty easily to create reviews using a more complex condition (based on how long its been since they last had a review, or the size of the checkin etc) however I've found the 5% rule to be fairly successful mainly because people have gotten used to the review feature and have started requesting code reviews manually for things they feel are important.

The major gotcha I found while coding this was the need to impersonate the user performing the checkin as the creator is the only user who can close the review (which isn't very useful when its the service account).