Added a friendly exception for invalid encryption keys

Also fixed a StackOverflow error in WebPushClient.SendNotification

Author: GurGaller

WebPush.Test/WebPushClientTest.cs

@@ -5,6 +5,7 @@
 using System.Linq;
 using System.Net;
 using System.Net.Http;
+using WebPush.Model;
 
 namespace WebPush.Test
 {
@@ -73,7 +74,8 @@ public void TestSetGcmApiKey()
         [TestMethod]
         public void TestSetGCMAPIKeyEmptyString()
         {
-            Assert.ThrowsException<ArgumentException>(delegate { client.SetGcmApiKey(""); });
+            Assert.ThrowsException<ArgumentException>(delegate
+            { client.SetGcmApiKey(""); });
         }
 
         [TestMethod]
@@ -85,8 +87,7 @@ public void TestSetGcmApiKeyNonGcmPushService()
             var subscription = new PushSubscription(TestFirefoxEndpoint, TestPublicKey, TestPrivateKey);
             var message = client.GenerateRequestDetails(subscription, @"test payload");
 
-            IEnumerable<string> values;
-            Assert.IsFalse(message.Headers.TryGetValues(@"Authorization", out values));
+            Assert.IsFalse(message.Headers.TryGetValues(@"Authorization", out var values));
         }
 
         [TestMethod]
@@ -98,15 +99,14 @@ public void TestSetGcmApiKeyNull()
             var subscription = new PushSubscription(TestGcmEndpoint, TestPublicKey, TestPrivateKey);
             var message = client.GenerateRequestDetails(subscription, @"test payload");
 
-            IEnumerable<string> values;
-            Assert.IsFalse(message.Headers.TryGetValues("Authorization", out values));
+            Assert.IsFalse(message.Headers.TryGetValues("Authorization", out var values));
         }
 
         [TestMethod]
         public void TestSetVapidDetails()
         {
             client.SetVapidDetails(TestSubject, TestPublicKey, TestPrivateKey);
-            
+
             var subscription = new PushSubscription(TestFirefoxEndpoint, TestPublicKey, TestPrivateKey);
             var message = client.GenerateRequestDetails(subscription, @"test payload");
             var authorizationHeader = message.Headers.GetValues(@"Authorization").First();
@@ -161,9 +161,21 @@ public void TestHandlingFailureMessages(HttpStatusCode status, string response,
             Assert.AreEqual(expectedMessage, actual.Message);
         }
 
-        private void TestSendNotification(HttpStatusCode status, string response=null)
+        [TestMethod]
+        [DataRow(1)]
+        [DataRow(5)]
+        [DataRow(10)]
+        [DataRow(50)]
+        public void TestHandleInvalidPublicKeys(int charactersToDrop)
         {
-            var subscription = new PushSubscription(TestFcmEndpoint, TestPublicKey, TestPrivateKey);
+            var invalidKey = TestPublicKey.Substring(0, TestPublicKey.Length - charactersToDrop);
+
+            Assert.ThrowsException<InvalidEncryptionDetailsException>(() => TestSendNotification(HttpStatusCode.OK, response: null, invalidKey));
+        }
+
+        private void TestSendNotification(HttpStatusCode status, string response = null, string publicKey = TestPublicKey)
+        {
+            var subscription = new PushSubscription(TestFcmEndpoint, publicKey, TestPrivateKey);
             var httpContent = response == null ? null : new StringContent(response);
             httpMessageHandlerMock.When(TestFcmEndpoint).Respond(new HttpResponseMessage { StatusCode = status, Content = httpContent });
             client.SetVapidDetails(TestSubject, TestPublicKey, TestPrivateKey);

WebPush/Model/InvalidEncryptionDetailsException.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace WebPush.Model
+{
+    public class InvalidEncryptionDetailsException : Exception
+    {
+        public InvalidEncryptionDetailsException(string message, PushSubscription pushSubscription)
+            : base(message)
+        {
+            PushSubscription = pushSubscription;
+        }
+
+        public PushSubscription PushSubscription { get; }
+    }
+}

WebPush/WebPushClient.cs

@@ -6,6 +6,7 @@
 using System.Runtime.CompilerServices;
 using System.Threading;
 using System.Threading.Tasks;
+using WebPush.Model;
 using WebPush.Util;
 
 [assembly: InternalsVisibleTo("WebPush.Test")]
@@ -202,7 +203,7 @@ public HttpRequestMessage GenerateRequestDetails(PushSubscription subscription,
                         @"Unable to send a message with payload to this subscription since it doesn't have the required encryption key");
                 }
 
-                var encryptedPayload = Encryptor.Encrypt(subscription.P256DH, subscription.Auth, payload);
+                var encryptedPayload = EncryptPayload(subscription, payload);
 
                 request.Content = new ByteArrayContent(encryptedPayload.Payload);
                 request.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
@@ -243,7 +244,8 @@ public HttpRequestMessage GenerateRequestDetails(PushSubscription subscription,
                 {
                     cryptoKeyHeader += @";" + vapidHeaders["Crypto-Key"];
                 }
-            } else if (isFcm && !string.IsNullOrEmpty(currentGcmApiKey))
+            }
+            else if (isFcm && !string.IsNullOrEmpty(currentGcmApiKey))
             {
                 request.Headers.TryAddWithoutValidation("Authorization", "key=" + currentGcmApiKey);
             }
@@ -252,6 +254,23 @@ public HttpRequestMessage GenerateRequestDetails(PushSubscription subscription,
             return request;
         }
 
+        private static EncryptionResult EncryptPayload(PushSubscription subscription, string payload)
+        {
+            try
+            {
+                return Encryptor.Encrypt(subscription.P256DH, subscription.Auth, payload);
+            }
+            catch (Exception ex)
+            {
+                if (ex is FormatException || ex is ArgumentException)
+                {
+                    throw new InvalidEncryptionDetailsException("Unable to encrypt the payload with the encryption key of this subscription.", subscription);
+                }
+
+                throw;
+            }
+        }
+
         /// <summary>
         ///     To send a push notification call this method with a subscription, optional payload and any options
         ///     Will exception if unsuccessful
@@ -265,9 +284,8 @@ public HttpRequestMessage GenerateRequestDetails(PushSubscription subscription,
         public void SendNotification(PushSubscription subscription, string payload = null,
             Dictionary<string, object> options = null)
         {
-            SendNotification(subscription, payload, options);
+            SendNotificationAsync(subscription, payload, options).GetAwaiter().GetResult();
         }
-        
 
         /// <summary>
         ///     To send a push notification call this method with a subscription, optional payload and any options
@@ -294,7 +312,7 @@ public void SendNotification(PushSubscription subscription, string payload, stri
             var options = new Dictionary<string, object> { ["gcmAPIKey"] = gcmApiKey };
             SendNotification(subscription, payload, options);
         }
-        
+
 
         /// <summary>
         ///     To send a push notification asynchronous call this method with a subscription, optional payload and any options
@@ -308,7 +326,7 @@ public void SendNotification(PushSubscription subscription, string payload, stri
         /// </param>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         public async Task SendNotificationAsync(PushSubscription subscription, string payload = null,
-            Dictionary<string, object> options = null, CancellationToken cancellationToken=default)
+            Dictionary<string, object> options = null, CancellationToken cancellationToken = default)
         {
             var request = GenerateRequestDetails(subscription, payload, options);
             var response = await HttpClient.SendAsync(request, cancellationToken);
@@ -325,7 +343,7 @@ public async Task SendNotificationAsync(PushSubscription subscription, string pa
         /// <param name="vapidDetails">The vapid details for the notification.</param>
         /// <param name="cancellationToken"></param>
         public async Task SendNotificationAsync(PushSubscription subscription, string payload,
-            VapidDetails vapidDetails, CancellationToken cancellationToken=default)
+            VapidDetails vapidDetails, CancellationToken cancellationToken = default)
         {
             var options = new Dictionary<string, object> { ["vapidDetails"] = vapidDetails };
             await SendNotificationAsync(subscription, payload, options, cancellationToken);
@@ -339,7 +357,7 @@ public async Task SendNotificationAsync(PushSubscription subscription, string pa
         /// <param name="payload">The payload you wish to send to the user</param>
         /// <param name="gcmApiKey">The GCM API key</param>
         /// <param name="cancellationToken"></param>
-        public async Task SendNotificationAsync(PushSubscription subscription, string payload, string gcmApiKey, CancellationToken cancellationToken=default)
+        public async Task SendNotificationAsync(PushSubscription subscription, string payload, string gcmApiKey, CancellationToken cancellationToken = default)
         {
             var options = new Dictionary<string, object> { ["gcmAPIKey"] = gcmApiKey };
             await SendNotificationAsync(subscription, payload, options, cancellationToken);