Azure FunctionsでToken Bindingを使って、Azure Active DirectoryによるOAuth認証をラクチンにする

function.cs

using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;

namespace hoge
{
    public static class Function
    {
        [FunctionName("Function")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
            [Token(IdentityProvider = "AAD", Resource = "https://graph.microsoft.com/", Identity = TokenIdentityMode.ClientCredentials)]string graphToken,
            ILogger log)
        {
            log.LogInformation("Access Token:" + graphToken);

            string name = req.Query["name"];

            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            dynamic data = JsonConvert.DeserializeObject(requestBody);
            name = name ?? data?.name;

            return name != null
                ? (ActionResult)new OkObjectResult($"Hello, {name}")
                : new BadRequestObjectResult("Please pass a name on the query string or in the request body");
        }
    }
}