Make client keys handling case insensitive (#26)

Author: tpeczek

src/Lib.Net.Http.WebPush/PushServiceClient.cs

@@ -291,10 +291,18 @@ private static HttpRequestMessage SetContent(HttpRequestMessage pushMessageDeliv
             }
             else
             {
+                string p256dhKey = subscription.GetKey(PushEncryptionKeyName.P256DH);
+                string authKey = subscription.GetKey(PushEncryptionKeyName.Auth);
+
+                if (String.IsNullOrWhiteSpace(p256dhKey) || String.IsNullOrWhiteSpace(authKey))
+                {
+                    throw new InvalidOperationException("The client P-256 public key or authentication secret is not available");
+                }
+
                 ECDHAgreement keyAgreement = ECDHAgreementCalculator.CalculateAgreement
                 (
-                    UrlBase64Converter.FromUrlBase64String(subscription.GetKey(PushEncryptionKeyName.P256DH)),
-                    UrlBase64Converter.FromUrlBase64String(subscription.GetKey(PushEncryptionKeyName.Auth))
+                    UrlBase64Converter.FromUrlBase64String(p256dhKey),
+                    UrlBase64Converter.FromUrlBase64String(authKey)
                 );
 
                 pushMessageDeliveryRequest.Content = new Aes128GcmEncodedContent(

src/Lib.Net.Http.WebPush/PushSubscription.cs

@@ -1,4 +1,6 @@
-using System.Collections.Generic;
+using System;
+using System.Linq;
+using System.Collections.Generic;
 
 namespace Lib.Net.Http.WebPush
 {
@@ -37,6 +39,10 @@ public string GetKey(PushEncryptionKeyName keyName)
                 {
                     key = Keys[keyNameStringified];
                 }
+                else
+                {
+                    key = Keys.SingleOrDefault(x => String.Equals(x.Key, keyNameStringified, StringComparison.OrdinalIgnoreCase)).Value;
+                }
             }
 
             return key;