Implementing ServiceLocator in middleware

Question

Before I begin, I'm aware the Service Locator pattern is not recommended and it's better to inject services into the classes where they are used. However, I have a large legacy codebase that creates a lot of objects inside methods without DI. Refactoring this would be a monumental task so I am trying to implement a static Service Locator as reasonably as possible.

My idea is to create a scope as part of a request middleware and set the ServiceLocator instance here. Then allow it to flow through the rest of the request chain before it exists and disposes. I have tested this and my created class is disposed, so it seems to be working as expected. Are there any pitfalls I haven't considered?

public class DependencyLocatorHandler(RequestDelegate next, IServiceProvider serviceProvider)
{
 public async Task InvokeAsync(HttpContext context)
 {
 await using var serviceProviderScope = serviceProvider.CreateAsyncScope();
 ServiceLocator.SetServiceProvider(serviceProviderScope.ServiceProvider);
 await next(context);
 }
}
public static class ServiceLocator
{
 private static IServiceProvider _serviceProvider;
 public static void SetServiceProvider(IServiceProvider serviceProvider)
 {
 _serviceProvider = serviceProvider;
 }
 public static T GetService<T>()
 {
 return _serviceProvider.GetService<T>();
 }
}

• Basilevs: Will not work for multithreading.
• Greg Burghardt: And accessing any sort of shared state from a static context will kill you application's ability to serve multiple requests by the same user concurrently if you have IIS configured for sticky sessions.
• Steve: I was worried about this. But what other option do I have?
• Greg Burghardt: Can you use OWIN -- is your application old enough to use that? I think the trick here is to initialize the service locator as an object at the beginning of your pipeline. Then each middleware component can pull it out of the current HTTP context.
• Steve: No, it's dotnet 9.