.NET Core Response Header Middleware

ResponseHeaderMiddleware.cs

using System.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;

namespace MyApplication
{
    public class ResponseHeaderMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly IDictionary<string, string> _headers;

        public ResponseHeaderMiddleware(RequestDelegate next, IDictionary<string, string> headers)
        {
            _next = next;
            _headers = headers;
        }

        public async Task InvokeAsync(HttpContext context)
        {
            foreach (var header in _headers)
            {
                context.Response.Headers[header.Key] = header.Value;
            }

            await _next(context);
        }
    }
    
    public static class ResponseHeaderMiddlewareExtensions {
        public static IApplicationBuilder UseResponseHeaders(this IApplicationBuilder builder, IDictionary<string, string> headers)
        {
            return builder.UseMiddleware<ResponseHeaderMiddleware>(headers);
        }
    }
}

Startup.cs

namespace MyApplication
{
    public class Startup
    {
        public void Configure(IApplicationBuilder app)
        {
            app.UseResponseHeaders(new Dictionary<string, string>
            {
                {"Referrer-Policy", "no-referrer"}
            });
        }
    }
}