Can no longer access the list of API descriptors after installing Glimpse - asp.net-mvc-4

Question

We would like to use Glimpse in our ASP.net MVC project but are running into a problem when accessing the list of Web API descriptors.
We have installed Glimpse.Mvc4 1.2.2 using the Nuget Package Manager.
The following snippet gets all API descriptors and it works fine before we install Glimpse. After installing we do only get an empty list.
IEnumerable<ApiDescription> apiDescriptors = System.Web.Http.GlobalConfiguration
.Configuration
.Services
.GetApiExplorer()
.ApiDescriptions
Does anyone know why this call does not work when Glimpse is installed?

Answer 1

The problem is that the Glimpse ASP.NET module wraps all routes in its own objects. So API Explorer ignores them (thinks that they are not Web API routes).
To work around this issue, you must initialize a fresh copy of System.Web.Http.HttpConfiguration instead of using GlobalConfiguration.Configuration.
// need to create a custom configuration instance because the default one can be
// processed by Glimpse and be thus full of wrapped routesthat the ApiExplorer
// does not recognize.
var config = new System.Web.Http.HttpConfiguration();
WebApiConfig.Register(config);
// these line is useful if you use WebAPI Help page package
HelpPageConfig.Register(config);
Controllers.HelpController.Configuration = config;
// otherwise just get the `IApiExplorer` interface from the fresh configuration:
var apis = config.Services.GetApiExplorer().ApiDescriptions;