Get user Claims from the Request Headers

ClaimsDemo.cs

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.Extensions.Logging;
using System.Security.Claims;
using System.Linq;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;

// DEMO: Get user Claims from the Request Headers
// Adopted from https://github.com/MaximRouiller/MaximeRouiller.Azure.AppService.EasyAuth
namespace ClaimsDemo.Function
{
    public static class ClaimsDemo
    {
        [FunctionName("ClaimsDemo")]
        public static IActionResult Run
        ([HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)]
        HttpRequest req, ILogger log)
        {

            //Extract User ID and Claims from the request headers
            var principal_name = req.Headers["X-MS-CLIENT-PRINCIPAL-NAME"].FirstOrDefault();
            var principal_Id = req.Headers["X-MS-CLIENT-PRINCIPAL-ID"].FirstOrDefault();
            string easyAuthProvider = req.Headers["X-MS-CLIENT-PRINCIPAL-IDP"].FirstOrDefault();
            string clientPrincipalEncoded = req.Headers["X-MS-CLIENT-PRINCIPAL"].FirstOrDefault();

            log.LogInformation("User ID: " + principal_name);
            log.LogInformation("User Principal ID: " + principal_Id);
            log.LogInformation("EasyAuth Provider: " + easyAuthProvider);
            log.LogInformation("Encoded Client Principal: " + clientPrincipalEncoded);

            //Decode the Client Principal
            byte[] decodedBytes = Convert.FromBase64String(clientPrincipalEncoded);
            string clientPrincipalDecoded = System.Text.Encoding.Default.GetString(decodedBytes);
            // log.LogInformation("Decoded Client Principal: " + clientPrincipalDecoded);

            ClientPrincipal clientPrincipal = JsonConvert.DeserializeObject<ClientPrincipal>(clientPrincipalDecoded);
            IEnumerable<Claim> claims = clientPrincipal.Claims.Select(x => new Claim(x.Type, x.Value));

            log.LogInformation("Claim Type : Claim Value");

            foreach (Claim claim in claims)
            {
                log.LogInformation(claim.Type + " : " + claim.Value + "\n");
            }

            return new OkObjectResult("Success");
        }
    }

    public class ClientPrincipal
    {
        [JsonProperty("auth_typ")]
        public string AuthenticationType { get; set; }
        [JsonProperty("claims")]
        public IEnumerable<UserClaim> Claims { get; set; }
        [JsonProperty("name_typ")]
        public string NameType { get; set; }
        [JsonProperty("role_typ")]
        public string RoleType { get; set; }
    }

    public class UserClaim
    {
        [JsonProperty("typ")]
        public string Type { get; set; }
        [JsonProperty("val")]
        public string Value { get; set; }
    }
}