Google Play Azure Function

run.csx

using System.Configuration;
using System.Net;
using Google.Apis.AndroidPublisher.v2;
using Google.Apis.AndroidPublisher.v2.Data;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Services;

private static string GooglePlayAccount = ConfigurationManager.AppSettings["GooglePlayAccount"];
//NOTE: best way I could get \n in an app setting
private static string GooglePlayKey = ConfigurationManager.AppSettings["GooglePlayKey"].Replace("\\n", "\n");

private static ServiceAccountCredential _credential = new ServiceAccountCredential
(
    new ServiceAccountCredential.Initializer(GooglePlayAccount)
    {
        Scopes = new[] { AndroidPublisherService.Scope.Androidpublisher }
    }.FromPrivateKey(GooglePlayKey)
);
private static AndroidPublisherService _googleService = new AndroidPublisherService
(
    new BaseClientService.Initializer
    {
        HttpClientInitializer = _credential,
        ApplicationName = "Azure Function",
    }
);

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    var receipt = await req.Content.ReadAsAsync<GoogleReceipt>();
    
    if (string.IsNullOrEmpty(receipt.Id) || string.IsNullOrEmpty(receipt.TransactionId) || string.IsNullOrEmpty(receipt.DeveloperPayload))
        return req.CreateResponse(HttpStatusCode.BadRequest);

    log.Info($"IAP receipt: {receipt.Id}, {receipt.TransactionId}");

    try
    {
        var request = _googleService.Purchases.Products.Get(receipt.BundleId, receipt.Id, receipt.PurchaseToken);
        var purchaseState = await request.ExecuteAsync();

        if (purchaseState.DeveloperPayload != receipt.DeveloperPayload)
        {
            log.Info($"IAP invalid, DeveloperPayload did not match!");
            return req.CreateResponse(HttpStatusCode.BadRequest);
        }   
        if (purchaseState.PurchaseState != 0)
        {
            log.Info($"IAP invalid, purchase was cancelled or refunded!");
            return req.CreateResponse(HttpStatusCode.BadRequest);
        }
    }
    catch (Exception exc)
    {
        log.Info($"IAP invalid, error reported: " + exc.Message);
        return req.CreateResponse(HttpStatusCode.BadRequest);
    }

    log.Info($"IAP Success: {receipt.Id}, {receipt.TransactionId}");
    return req.CreateResponse(HttpStatusCode.OK);
}