Client response QR code size reduced. Cloud provider support.

QRBee.Core/Data/ClientToMerchantResponse.cs

@@ -16,7 +16,7 @@
         /// Convert ClientToMerchantResponse to string to be used as QR Code source (along with client signature)
         /// </summary>
         /// <returns> Converted string</returns>
-        public string AsQRCodeString() => $"{AsDataForSignature()}|{ClientSignature}";
+        public string AsQRCodeString() => $"{ClientId}|{TimeStampUTC:O}|{ClientSignature}";
 
         public string AsDataForSignature() => $"{ClientId}|{TimeStampUTC:O}|{MerchantRequest.AsQRCodeString()}";
 
@@ -31,15 +31,14 @@
             var s = input.Split('|');
             if (s.Length < 3)
             {
-                throw new ApplicationException("Expected 3 or more elements");
+                throw new ApplicationException($"Expected 3 or more elements but got {s.Length}");
             }
 
             var res = new ClientToMerchantResponse()
             {
-                MerchantRequest = MerchantToClientRequest.FromString(string.Join("|", s.Skip(2))),
+                ClientId        = s[0],
-                ClientId = s[0],
+                TimeStampUTC    = DateTime.ParseExact(s[1], "O", null),
-                TimeStampUTC = DateTime.ParseExact(s[1], "O", null),
+                ClientSignature = s[2]
-                ClientSignature = s[3]
             };
 
             return res;

QRBee.Core/Data/MerchantToClientRequest.cs

@@ -33,9 +33,9 @@ namespace QRBee.Core.Data
         public static MerchantToClientRequest FromString(string input)
         {
             var s = input.Split('|');
-            if (s.Length != 6)
+            if (s.Length < 6)
             {
-                throw new ApplicationException("Expected 6 elements");
+                throw new ApplicationException($"Expected 6 elements but got {s.Length}");
             }
 
             var res = new MerchantToClientRequest

QRBee.Core/Data/PaymentRequest.cs

@@ -13,18 +13,6 @@
         /// Convert PaymentRequest to string
         /// </summary>
         /// <returns>Converted string</returns>
-        public string AsString() => ClientResponse.AsQRCodeString();
+        public string AsString() => $"{ClientResponse.AsDataForSignature()}|{ClientResponse.ClientSignature}";
-
-        public static PaymentRequest FromString(string input)
-        {
-            if (string.IsNullOrWhiteSpace(input))
-            {
-                throw new ApplicationException("The input is wrong!");
-            }
-
-            //doesn't work
-            var response = ClientToMerchantResponse.FromString(input);
-            return new PaymentRequest(){ClientResponse = response};
-        }
     }
 }

QRBee/QRBee.Android/Resources/Resource.designer.cs

@@ -14,7 +14,7 @@ namespace QRBee.Droid
 {
 	
 	
-	[global::System.CodeDom.Compiler.GeneratedCodeAttribute("Xamarin.Android.Build.Tasks", "12.2.0.155")]
+	[global::System.CodeDom.Compiler.GeneratedCodeAttribute("Xamarin.Android.Build.Tasks", "12.1.0.11")]
 	public partial class Resource
 	{
 		

QRBee/QRBee.Android/Services/LocalSettings.cs

@@ -9,7 +9,13 @@ namespace QRBee.Droid.Services
 {
     internal class LocalSettings : ILocalSettings
     {
+        // Use https://10.0.2.2:7000 if you are running in emulator and API server on localhost
+#if false
         public string QRBeeApiUrl => "https://10.0.2.2:7000";
+#else
+        public string QRBeeApiUrl => "https://qrbee-api.azurewebsites.net/";
+#endif
+
 
         public async Task SaveSettings(Settings settings)
         {

QRBee/QRBee/ViewModels/MerchantPageViewModel.cs

@@ -17,6 +17,8 @@ namespace QRBee.ViewModels
         private decimal _amount;
         private string _qrCode;
 
+        private MerchantToClientRequest _lastRequest;
+
         public Command GenerateQrCommand { get; }
         public Command ScanCommand{ get; }
 
@@ -42,7 +44,13 @@ namespace QRBee.ViewModels
                 var client = new HttpClient(GetInsecureHandler());
 
                 var service = new Core.Client.Client(_settings.QRBeeApiUrl, client);
-                var paymentRequest = PaymentRequest.FromString(result);
+                var clientResponse = ClientToMerchantResponse.FromString(result);
+
+                clientResponse.MerchantRequest = _lastRequest;
+                var paymentRequest = new PaymentRequest
+                {
+                    ClientResponse = clientResponse
+                };
 
                 //QrCode = null;
                 IsVisible = false;
@@ -152,19 +160,21 @@ namespace QRBee.ViewModels
             }
             else
             {
-                var trans = new MerchantToClientRequest
+                var request = new MerchantToClientRequest
                 {
-                    MerchantId = _settings.LoadSettings().ClientId,
+                    MerchantId            = _settings.LoadSettings().ClientId,
                     MerchantTransactionId = Guid.NewGuid().ToString("D"),
-                    Name = Name,
+                    Name                  = Name,
-                    Amount = Amount,
+                    Amount                = Amount,
-                    TimeStampUTC = DateTime.UtcNow
+                    TimeStampUTC          = DateTime.UtcNow
                 };
 
-                var merchantSignature = _securityService.Sign(Encoding.UTF8.GetBytes(trans.AsDataForSignature()));
+                var merchantSignature = _securityService.Sign(Encoding.UTF8.GetBytes(request.AsDataForSignature()));
-                trans.MerchantSignature = Convert.ToBase64String(merchantSignature);
+                request.MerchantSignature = Convert.ToBase64String(merchantSignature);
 
-                QrCode = trans.AsQRCodeString();
+                _lastRequest = request;
+
+                QrCode = request.AsQRCodeString();
                 IsVisible = true;
             }
 

QRBee/QRBee/ViewModels/RegisterViewModel.cs

@@ -124,7 +124,7 @@ namespace QRBee.ViewModels
 
                 await _settings.SaveSettings(settings);
 
-                //if (!_privateKeyHandler.Exists())
+                if (!_privateKeyHandler.Exists())
                 {
                     _privateKeyHandler.GeneratePrivateKey(settings.Name);
                 }

QRBeeApi/Services/Database/CertificateInfo.cs

@@ -5,9 +5,10 @@ namespace QRBee.Api.Services.Database
     public class CertificateInfo
     {
 
-        [BsonId] public string? Id { get; set; }
+        [BsonId] public string? Id      { get; set; }
-        public string? ClientId { get; set; }
+        public string? ClientId         { get; set; }
-        public string? Certificate { get; set; }
+        public string? Email            { get; set; }
+        public string? Certificate      { get; set; }
         public DateTime ServerTimeStamp { get; set; }
     }
 }

QRBeeApi/Services/Database/Storage.cs

@@ -121,7 +121,7 @@ namespace QRBee.Api.Services.Database
                 throw new ApplicationException("Info Id is null.");
             }
 
-            var certificate = await TryGetCertificateInfo(info.Id);
+            var certificate = await TryGetCertificateInfoByEmail(info.Email ?? throw new ApplicationException("Email is not set"));
 
             if (certificate == null)
             {
@@ -130,7 +130,10 @@ namespace QRBee.Api.Services.Database
                 return;
             }
 
-            _logger.LogInformation($"Found certificate with ID: {info.Id}");
+            await collection.DeleteOneAsync($"{{ _id: \"{certificate.Id}\" }}");
+            await collection.ReplaceOneAsync($"{{ _id: \"{info.Id}\" }}", info, new ReplaceOptions() { IsUpsert = true });
+
+            _logger.LogInformation($"Found certificate with old ID: {certificate.Id} and replaced with new ID: {info.Id}");
 
         }
 
@@ -151,6 +154,23 @@ namespace QRBee.Api.Services.Database
             return cursor.Current.FirstOrDefault();
         }
 
+        /// <summary>
+        /// Try to find if the Certificate already exists in the database
+        /// </summary>
+        /// <param name="email">parameter by which to find CertificateInfo</param>
+        /// <returns>null if certificate doesn't exist or CertificateInfo</returns>
+        private async Task<CertificateInfo?> TryGetCertificateInfoByEmail(string email)
+        {
+            var collection = _database.GetCollection<CertificateInfo>("Certificates");
+            using var cursor = await collection.FindAsync($"{{ Email: \"{email}\" }}");
+            if (!await cursor.MoveNextAsync())
+            {
+                return null;
+            }
+
+            return cursor.Current.FirstOrDefault();
+        }
+
         public async Task<CertificateInfo> GetCertificateInfoByCertificateId(string id)
         {
             var certificate = await TryGetCertificateInfo(id);

QRBeeApi/Services/QRBeeAPIService.cs

@@ -57,7 +57,7 @@ namespace QRBee.Api.Services
 
             var clientCertificate =  _securityService.CreateCertificate(clientId,bytes);
             
-            var convertedClientCertificate = Convert(clientCertificate, clientId);
+            var convertedClientCertificate = Convert(clientCertificate, clientId,request.Email);
             await _storage.InsertCertificate(convertedClientCertificate);
 
             return new RegistrationResponse
@@ -126,62 +126,78 @@ namespace QRBee.Api.Services
 
         public async Task<PaymentResponse> Pay(PaymentRequest value)
         {
-            //1. Check payment request parameters for validity
+            try
-            ValidateTransaction(value);
-
-            //2. Check client signature
-            var t2 = CheckSignature(
-                value.ClientResponse.AsDataForSignature(),
-                value.ClientResponse.ClientSignature,
-                value.ClientResponse.ClientId);
-
-            //3. Check merchant signature
-            var t3 = CheckSignature(
-                value.ClientResponse.MerchantRequest.AsDataForSignature(),
-                value.ClientResponse.MerchantRequest.MerchantSignature,
-                value.ClientResponse.MerchantRequest.MerchantId);
-
-            //4. Check if transaction was already processed
-            var t4 = CheckTransaction(value.ClientResponse.MerchantRequest.MerchantTransactionId);
-
-            //Parallel task execution
-            await Task.WhenAll(t2, t3, t4);
-
-            //5. Decrypt client card data
-            var clientCardData = DecryptClientData(value.ClientResponse.EncryptedClientCardData);
-
-            //6. Check client card data for validity
-            await CheckClientCardData(clientCardData);
-
-            //7. Register preliminary transaction record with expiry of one minute
-            var info = Convert(value);
-            info.Status = TransactionInfo.TransactionStatus.Pending;
-
-            await _storage.PutTransactionInfo(info);
-
-            //8. Send client card data to a payment gateway
-            var res = await _paymentGateway.Payment(info, clientCardData);
-
-            //9. Record transaction with result
-            if (res.Success)
             {
-                info.Status=TransactionInfo.TransactionStatus.Succeeded;
+                //1. Check payment request parameters for validity
-            }
+                ValidateTransaction(value);
-            else
+
-            {
+                //2. Check client signature
-                info.Status = TransactionInfo.TransactionStatus.Rejected;
+                var t2 = CheckSignature(
-                info.RejectReason = res.ErrorMessage;
+                    value.ClientResponse.AsDataForSignature(),
-            }
+                    value.ClientResponse.ClientSignature,
-            await _storage.UpdateTransaction(info);
+                    value.ClientResponse.ClientId);
+
+                //3. Check merchant signature
+                var t3 = CheckSignature(
+                    value.ClientResponse.MerchantRequest.AsDataForSignature(),
+                    value.ClientResponse.MerchantRequest.MerchantSignature,
+                    value.ClientResponse.MerchantRequest.MerchantId);
+
+                //4. Check if transaction was already processed
+                var t4 = CheckTransaction(value.ClientResponse.MerchantRequest.MerchantTransactionId);
+
+                //Parallel task execution
+                await Task.WhenAll(t2, t3, t4);
+
+                //5. Decrypt client card data
+                var clientCardData = DecryptClientData(value.ClientResponse.EncryptedClientCardData);
+
+                //6. Check client card data for validity
+                await CheckClientCardData(clientCardData);
+
+                //7. Register preliminary transaction record with expiry of one minute
+                var info = Convert(value);
+                info.Status = TransactionInfo.TransactionStatus.Pending;
+
+                await _storage.PutTransactionInfo(info);
+
+                //8. Send client card data to a payment gateway
+                var res = await _paymentGateway.Payment(info, clientCardData);
+
+                //9. Record transaction with result
+                if (res.Success)
+                {
+                    info.Status=TransactionInfo.TransactionStatus.Succeeded;
+                }
+                else
+                {
+                    info.Status = TransactionInfo.TransactionStatus.Rejected;
+                    info.RejectReason = res.ErrorMessage;
+                }
+                await _storage.UpdateTransaction(info);
+
+                //10. Make response for merchant
+                var response = MakePaymentResponse(value, info.TransactionId ?? "", info.Status==TransactionInfo.TransactionStatus.Succeeded, info.RejectReason);
+                return response;
+            }
+            catch (Exception e)
+            {
+                var response = MakePaymentResponse(value, "", false, e.Message);
+                return response;
+            }
+            
+        }
+
+        private PaymentResponse MakePaymentResponse(PaymentRequest value, string transactionId, bool result = true, string? errorMessage = null)
+        {
             
-            //10. Make response for merchant
             var response = new PaymentResponse
             {
-                ServerTransactionId = info.TransactionId,
+                ServerTransactionId = transactionId,
                 PaymentRequest = value,
                 ServerTimeStampUTC = DateTime.UtcNow,
-                Success = res.Success,
+                Success = result,
-                RejectReason = res.ErrorMessage,
+                RejectReason = errorMessage,
             };
 
             var signature = _securityService.Sign(Encoding.UTF8.GetBytes(response.AsDataForSignature()));
@@ -224,7 +240,7 @@ namespace QRBee.Api.Services
             
             if (!check)
             {
-                throw new ApplicationException($"Signature is incorrect for Id: {id}.");
+                throw new ApplicationException($"Signature is incorrect for Id: {id}. Data: {data}");
             }
         }
 
@@ -309,13 +325,14 @@ namespace QRBee.Api.Services
             return new TransactionInfo(request, DateTime.UtcNow);
         }
 
-        private CertificateInfo Convert(X509Certificate2 certificate, string clientId)
+        private CertificateInfo Convert(X509Certificate2 certificate, string clientId, string email)
         {
             var convertedCertificate = _securityService.Serialize(certificate);
             return new CertificateInfo
             {
                 Id              = certificate.SerialNumber, 
                 ClientId        = clientId,
+                Email           = email,
                 Certificate     = convertedCertificate, 
                 ServerTimeStamp = DateTime.UtcNow
             };