Check whether the call into UseHttpCacheHeaders is situated between UseRouting and UseEndpoints

[KevinDockx]

Check whether the call into UseHttpCacheHeaders is situated between UseRouting and UseEndpoints - allows for throwing a nice Exception to inform users of this.

Cfr: https://github.com/dotnet/aspnetcore/blob/main/src/Http/Routing/src/Builder/EndpointRoutingApplicationBuilderExtensions.cs#L135

[KevinDockx]

RoutingMarkerService is internal - cannot use this to check. Consider ASP.NET Core feature request.

https://github.com/dotnet/aspnetcore/blob/main/src/Http/Routing/src/Builder/EndpointRoutingApplicationBuilderExtensions.cs#L122

[KevinDockx]

Feature request: dotnet/aspnetcore#37679

[KevinDockx]

As per Javier's answer on the feature request: for now, use the alternative and check if we can resolve a publicly exposed type, like EndpointDataSource.

In the future, consider an analyzer.

[KevinDockx]

#102

[KevinDockx]

Answer isn't sufficient: checking the registered type only checks whether a service is registered on a container, NOT the order in which middleware is added to the request pipeline...

• leave in the check for the required services for stability reasons in v6
• think about analyzer approach for vNext