Simple Azure Function based on the HTTP Trigger sample code, with the addition of the token validation call

AuthTest.cs

using System;
using System.IdentityModel.Tokens.Jwt;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Security.Claims;
using System.Threading.Tasks;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.Azure.WebJobs.Host;

namespace SpotterPowerlifting.Functions
{
    public static class AuthTest
    {
        [FunctionName("AuthTest")]
        public static async Task<HttpResponseMessage> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)]HttpRequestMessage req, TraceWriter log)
        {
            log.Info("C# HTTP trigger function processed a request.");

            ClaimsPrincipal principal;
            if ((principal = await Security.ValidateTokenAsync(req.Headers.Authorization)) == null)
            {
                return req.CreateResponse(HttpStatusCode.Unauthorized);
            }

            // parse query parameter
            string name = req.GetQueryNameValuePairs()
                .FirstOrDefault(q => string.Compare(q.Key, "name", true) == 0)
                .Value;

            // Get request body
            dynamic data = await req.Content.ReadAsAsync<object>();

            // Set name to query string or body data
            name = name ?? data?.name;

            return name == null
                ? req.CreateResponse(HttpStatusCode.BadRequest, "Please pass a name on the query string or in the request body")
                : req.CreateResponse(HttpStatusCode.OK, "Hello " + name);
        }
    }
}

What packages do you need for this? Because as a csx func it's failing to recognise Security.ValidateTokenAsync() and i can't seem to make it work in a netcoreapp2.1 proj app either?