PluralKit/PluralKit.API/Middleware/AuthorizationTokenHandlerMiddleware.cs

using System.Threading.Tasks;

using Microsoft.AspNetCore.Http;

using Dapper;

using PluralKit.Core;

namespace PluralKit.API
{
    public class AuthorizationTokenHandlerMiddleware
    {
        private readonly RequestDelegate _next;
        public AuthorizationTokenHandlerMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task Invoke(HttpContext ctx, IDatabase db)
        {
            ctx.Request.Headers.TryGetValue("authorization", out var authHeaders);
            if (authHeaders.Count > 0)
            {
                var systemId = await db.Execute(conn => conn.QuerySingleOrDefaultAsync<SystemId?>(
                    "select id from systems where token = @token",
                    new { token = authHeaders[0] }
                ));

                if (systemId != null)
                    ctx.Items.Add("SystemId", systemId);
            }

            await _next.Invoke(ctx);
        }
    }
}