Enrich http handler 18

[gratinierer]

An implementation to #18.
With that changes I'm able to manipulate the HttpClientHandler and e.g. fetch Certificates from the Windows CertStore and add them to the requests, so Authentication with Mutual SSL becomes possible:

        private ConnectionPreferences GetConnectionPreferences()
        {
            if (_connectionPreferences == null)
            {
                _connectionPreferences = new ConnectionPreferences
                {
                    HttpClientHandlerEnricher = h =>
                        SetCertificateConfiguration(h, InstanceConfiguration.KeyStoreCertificateConfiguration)
                };
            }
            return _connectionPreferences;
        }

        protected void SetCertificateConfiguration(HttpClientHandler handler,
            KeyStoreCertificate keyStoreCertificateConfiguration)
        {
            if (keyStoreCertificateConfiguration != null)
            {
                Log.Debug(
                    $"Looking for certificate '{keyStoreCertificateConfiguration.CertificateName}' in store '{keyStoreCertificateConfiguration.KeyStoreName}'");
                using X509Store store = new X509Store(keyStoreCertificateConfiguration.KeyStoreName,
                    StoreLocation.CurrentUser);
                store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);
                var filteredCollection = store.Certificates
                    .Find(X509FindType.FindByKeyUsage, X509KeyUsageFlags.DigitalSignature, true).Find(
                        X509FindType.FindBySubjectName, keyStoreCertificateConfiguration.CertificateName, true);
                if (filteredCollection.Count != 1)
                {
                    throw new ClientCertificateSelectionException(
                        $"Expected exactly 1 Certificate with name '{keyStoreCertificateConfiguration.CertificateName}' in keystore '{keyStoreCertificateConfiguration.KeyStoreName}', but found {filteredCollection.Count}");
                }

                Log.Information($"Using Certificate '{filteredCollection[0].SubjectName.Name}'");
                handler.ClientCertificateOptions = ClientCertificateOption.Manual;
                handler.ClientCertificates.Add(filteredCollection[0]);
            }
        }

[gratinierer]

Hi @erdomke ,
can you give me an information, if you plan to integrate that pull request?
Thanks and best regards
miro

[erdomke]

Sorry. I finally got around to this. I tried something different that I am hoping is a bit cleaner in afcddad. Would that meet your needs?

[gratinierer]

Hi @erdomke,

cool, looks pretty much like the solution I wished I dared/was able to implement. During my test I got a little confused:
I had to add the following Line

      httpWebRequest.ClientCertificates = ClientCertificates;

to Innovator.Client.SyncClientHandler.CreateAndPrepareWebRequest.

Without adding this line, the httpClient seems to ignore the Certificates configured to the handler and not sending them to the server.
I think, that the combined usage HttpWebRequest and HttpClientHandler does not work as simple as in the minimal example i used for my tests:

        public static async Task Main(string[] args)
        {
            X509Store store = new X509Store("MY", StoreLocation.CurrentUser);
            store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);
            var filteredCollection = store.Certificates
                    .Find(X509FindType.FindByKeyUsage, X509KeyUsageFlags.DigitalSignature, true).Find(
                        X509FindType.FindBySubjectName, "aCertInTheTrusStore", true);
            var handler = new HttpClientHandler();
            handler.ClientCertificateOptions = ClientCertificateOption.Manual;
            handler.ClientCertificates.Add(filteredCollection[0]);
            var client = new HttpClient(handler);
            var response = await client.GetAsync("https://anUrl.com");
            Console.Out.WriteLine(await response.Content.ReadAsStringAsync());
            response.EnsureSuccessStatusCode();
        }

For my test with your code i build the lib with 'Innovator.Client.NetCore.csproj' on a core 3.1 environment.

Any idea how to get this working in a clean way?

Thanks for your great job!