RequestDelegateFactory should take an optional set of route pattern names or route parameter names

[davidfowl]

Background and Motivation

This would allow unattributed methods to disambiguate between route and query string when the method parameters are unattributed. Today we generate code that prefers route over query string and we could avoid that in certain cases. It would also allow us to better fail if the user used [FromRoute] and there was no route parameter with that name defined.

Proposed API

Since our overloads are getting a bit crazy with this change, I suggest we add an options object to handle the overflow.

public static class RequestDelegateFactory
{
-    public static RequestDelegate Create(Delegate action, IServiceProvider? serviceProvider)
+    public static RequestDelegate Create(Delegate action, Func<HttpContext, object>? targetFactory = null, RequestDelegateFactoryOptions? options = null)
-    public static RequestDelegate Create(MethodInfo methodInfo, Func<HttpContext, object>? targetFactory = null, IServiceProvider? serviceProvider)
+    public static RequestDelegate Create(MethodInfo methodInfo, Func<HttpContext, object>? targetFactory = null, RequestDelegateFactoryOptions? options = null)
}

+ public class RequestDelegateFactoryOptions
+ {
+     public IServiceProvider? ServiceProvider { get; init; }
+     public IReadOnlyList<string>? RouteParameterNames { get; init; }
+ }

Usage Examples

var options = new RequestDelegateFactoryOptions 
{ 
    ServiceProvider  = serviceProvider, 
    RouteParameterNames  = new[] { "id" }
};

var rd = RequestDelegateFactory.Create((int id) => id, options: options);

Alternative Designs

A single static method with optional parameters.

public static class RequestDelegateFactory
{
+    public static RequestDelegate Create(MethodInfo methodInfo, Func<HttpContext, object>? targetFactory = null, IServiceProvider? serviceProvider = null, IReadOnlyList<string>? routeParameterNames = null);
}

Risks

None

[davidfowl]

MVC skips binding sources that aren't from the request and that solves this problem, see

aspnetcore/src/Mvc/Mvc.ApiExplorer/src/DefaultApiDescriptionProvider.cs

Line 212 in a9a6831

if (!context.Results[i].Source.IsFromRequest)

aspnetcore/src/Mvc/Mvc.Abstractions/src/ModelBinding/BindingSource.cs

Line 84 in a9a6831

public static readonly BindingSource Services = new BindingSource(

cc @pranavkm

[halter73]

I almost used IsFromRequest instead of specifically checking for BindingSource.Services in #33727, but I didn't want to depend too much on BindingSource logic/conventions. The only other default non-IsFromRequest is BindingSource.Special.

I guess we could use BindingSource.Special to represent CancellationToken, HttpContext and things like that. Now those are just "services" as far as the EndpointMetadataApiDescriptionProvider is concerned but I don't think this matters much since it's all internal anyway.

[davidfowl]

I put this text on the wrong issue..

[pranavkm]

+ public class RequestDelegateFactoryOptions
+ {
+     public IServiceProvider? ServiceProvider { get; init; }
-     public IReadOnlyList<string>? RouteParameterNames { get; init; }
+    public IEnumerable<string>? RouteParameterNames { get; init; }
+ }