server/src/Core/Services/Implementations/AppleIapService.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Json;
using System.Text.Json.Serialization;
using System.Threading.Tasks;
using Bit.Billing.Models;
using Bit.Core.Repositories;
using Bit.Core.Settings;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace Bit.Core.Services
{
    public class AppleIapService : IAppleIapService
    {
        private readonly HttpClient _httpClient = new HttpClient();

        private readonly GlobalSettings _globalSettings;
        private readonly IWebHostEnvironment _hostingEnvironment;
        private readonly IMetaDataRepository _metaDataRespository;
        private readonly ILogger<AppleIapService> _logger;

        public AppleIapService(
            GlobalSettings globalSettings,
            IWebHostEnvironment hostingEnvironment,
            IMetaDataRepository metaDataRespository,
            ILogger<AppleIapService> logger)
        {
            _globalSettings = globalSettings;
            _hostingEnvironment = hostingEnvironment;
            _metaDataRespository = metaDataRespository;
            _logger = logger;
        }

        public async Task<AppleReceiptStatus> GetVerifiedReceiptStatusAsync(string receiptData)
        {
            var receiptStatus = await GetReceiptStatusAsync(receiptData);
            if (receiptStatus?.Status != 0)
            {
                return null;
            }
            var validEnvironment = _globalSettings.AppleIap.AppInReview ||
                (!(_hostingEnvironment.IsProduction() || _hostingEnvironment.IsEnvironment("QA")) && receiptStatus.Environment == "Sandbox") ||
                ((_hostingEnvironment.IsProduction() || _hostingEnvironment.IsEnvironment("QA")) && receiptStatus.Environment != "Sandbox");
            var validProductBundle = receiptStatus.Receipt.BundleId == "com.bitwarden.desktop" ||
                receiptStatus.Receipt.BundleId == "com.8bit.bitwarden";
            var validProduct = receiptStatus.LatestReceiptInfo.LastOrDefault()?.ProductId == "premium_annually";
            var validIds = receiptStatus.GetOriginalTransactionId() != null &&
                receiptStatus.GetLastTransactionId() != null;
            var validTransaction = receiptStatus.GetLastExpiresDate()
                .GetValueOrDefault(DateTime.MinValue) > DateTime.UtcNow;
            if (validEnvironment && validProductBundle && validProduct && validIds && validTransaction)
            {
                return receiptStatus;
            }
            return null;
        }

        public async Task SaveReceiptAsync(AppleReceiptStatus receiptStatus, Guid userId)
        {
            var originalTransactionId = receiptStatus.GetOriginalTransactionId();
            if (string.IsNullOrWhiteSpace(originalTransactionId))
            {
                throw new Exception("OriginalTransactionId is null");
            }
            await _metaDataRespository.UpsertAsync("AppleReceipt", originalTransactionId,
                new Dictionary<string, string>
                {
                    ["Data"] = receiptStatus.GetReceiptData(),
                    ["UserId"] = userId.ToString()
                });
        }

        public async Task<Tuple<string, Guid?>> GetReceiptAsync(string originalTransactionId)
        {
            var receipt = await _metaDataRespository.GetAsync("AppleReceipt", originalTransactionId);
            if (receipt == null)
            {
                return null;
            }
            return new Tuple<string, Guid?>(receipt.ContainsKey("Data") ? receipt["Data"] : null,
                receipt.ContainsKey("UserId") ? new Guid(receipt["UserId"]) : (Guid?)null);
        }

        private async Task<AppleReceiptStatus> GetReceiptStatusAsync(string receiptData, bool prod = true,
            int attempt = 0, AppleReceiptStatus lastReceiptStatus = null)
        {
            try
            {
                if (attempt > 4)
                {
                    throw new Exception("Failed verifying Apple IAP after too many attempts. Last attempt status: " +
                        lastReceiptStatus?.Status ?? "null");
                }

                var url = string.Format("https://{0}.itunes.apple.com/verifyReceipt", prod ? "buy" : "sandbox");

                var response = await _httpClient.PostAsJsonAsync(url, new AppleVerifyReceiptRequestModel
                {
                    ReceiptData = receiptData,
                    Password = _globalSettings.AppleIap.Password
                });

                if (response.IsSuccessStatusCode)
                {
                    var receiptStatus = await response.Content.ReadFromJsonAsync<AppleReceiptStatus>();
                    if (receiptStatus.Status == 21007)
                    {
                        return await GetReceiptStatusAsync(receiptData, false, attempt + 1, receiptStatus);
                    }
                    else if (receiptStatus.Status == 21005)
                    {
                        await Task.Delay(2000);
                        return await GetReceiptStatusAsync(receiptData, prod, attempt + 1, receiptStatus);
                    }
                    return receiptStatus;
                }
            }
            catch (Exception e)
            {
                _logger.LogWarning(e, "Error verifying Apple IAP receipt.");
            }
            return null;
        }
    }

    public class AppleVerifyReceiptRequestModel
    {
        [JsonPropertyName("receipt-data")]
        public string ReceiptData { get; set; }
        [JsonPropertyName("password")]
        public string Password { get; set; }
    }
}