PortBlog.API/PortBlog.API/Middleware/ApiKeyMiddleware.cs

using Microsoft.AspNetCore.Diagnostics;
using Microsoft.AspNetCore.Http.HttpResults;
using Microsoft.AspNetCore.Mvc;
using System.Net;

namespace PortBlog.API.Middleware
{
    public class ApiKeyMiddleware
    {
        private readonly RequestDelegate _next;
        private const string APIKEY = "XApiKey";
        public ApiKeyMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task InvokeAsync(HttpContext context)
        {
            if (!context.Request.Headers.TryGetValue(APIKEY, out var extractedApiKey))
            {
                context.Response.StatusCode = StatusCodes.Status401Unauthorized;
                await context.Response.WriteAsync("Unauthorized client");
                return;
            }

            var appSettings = context.RequestServices.GetRequiredService<IConfiguration>();

            var apiKey = appSettings.GetValue<string>(APIKEY);

            if (apiKey != null && !apiKey.Equals(extractedApiKey))
            {
                context.Response.StatusCode = StatusCodes.Status401Unauthorized;
                await context.Response.WriteAsync("Unauthorized client");
                return;
            }

            await _next(context);
        }
    }
}