System.Security.Cryptography fails on WASM (#25285)

Author: BrennanConroy

src/SignalR/clients/csharp/Http.Connections.Client/src/HttpConnectionFactory.cs

@@ -82,11 +82,10 @@ public async ValueTask<ConnectionContext> ConnectAsync(EndPoint endPoint, Cancel
         // Internal for testing
         internal static HttpConnectionOptions ShallowCopyHttpConnectionOptions(HttpConnectionOptions options)
         {
-            return new HttpConnectionOptions
+            var newOptions = new HttpConnectionOptions
             {
                 HttpMessageHandlerFactory = options.HttpMessageHandlerFactory,
                 Headers = options.Headers,
-                ClientCertificates = options.ClientCertificates,
                 Cookies = options.Cookies,
                 Url = options.Url,
                 Transports = options.Transports,
@@ -99,6 +98,14 @@ internal static HttpConnectionOptions ShallowCopyHttpConnectionOptions(HttpConne
                 DefaultTransferFormat = options.DefaultTransferFormat,
                 WebSocketConfiguration = options.WebSocketConfiguration,
             };
+
+            // WASM doesn't support Crypto APIs and our setter throws if you try to assign null
+            if (options.ClientCertificates != null)
+            {
+                newOptions.ClientCertificates = options.ClientCertificates;
+            }
+
+            return newOptions;
         }
     }
 }

src/SignalR/clients/csharp/Http.Connections.Client/src/HttpConnectionOptions.cs

@@ -10,6 +10,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Connections;
+using Microsoft.AspNetCore.Http.Connections.Client.Internal;
 
 namespace Microsoft.AspNetCore.Http.Connections.Client
 {
@@ -28,7 +29,13 @@ public class HttpConnectionOptions
         public HttpConnectionOptions()
         {
             _headers = new Dictionary<string, string>();
-            _clientCertificates = new X509CertificateCollection();
+
+            // System.Security.Cryptography isn't supported on WASM currently
+            if (!Utils.IsRunningInBrowser())
+            {
+                _clientCertificates = new X509CertificateCollection();
+            }
+
             _cookies = new CookieContainer();
 
             Transports = HttpTransports.All;