Add IHttpClientFactory Pattern to the PostmarkClients

CLAUDE.md

@@ -0,0 +1,66 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Commands
+
+```bash
+# Build
+dotnet build src/postmark-dotnet.sln
+
+# Run all tests (requires API tokens - see Testing section)
+dotnet test src/postmark-dotnet.sln
+
+# Run a single test class
+dotnet test src/Postmark.Tests/Postmark.Tests.csproj --filter "ClassName=ClientSendingTests"
+
+# Run a single test method
+dotnet test src/Postmark.Tests/Postmark.Tests.csproj --filter "FullyQualifiedName~ClientCanSendMessage"
+
+# Build NuGet package
+dotnet pack src/Postmark/Postmark.csproj
+```
+
+## Architecture
+
+This is a .NET Standard 2.0 HTTP client library for the [Postmark](https://postmarkapp.com) transactional email API. There are no web servers, databases, or startup code — only the library and its integration tests.
+
+**Client hierarchy:**
+
+- `PostmarkClientBase` — abstract base handling all HTTP communication. Contains the two core methods (`ProcessRequestAsync` for POST/PUT with body, `ProcessNoBodyRequestAsync` for GET/DELETE with query params). Uses a static `ClientFactory` property returning `ISimpleHttpClient` — replace this to mock HTTP in tests.
+- `PostmarkClient` — server-level API using `X-Postmark-Server-Token` header. Handles email sending, bounces, templates, message streams, suppressions, statistics, webhooks, and inbound messages.
+- `PostmarkAdminClient` — account-level API using `X-Postmark-Account-Token` header. Handles servers, sender signatures, and domains.
+- `PostmarkClientExtensions` — convenience overloads for `SendMessageAsync` (accepts primitives instead of a `PostmarkMessage` object).
+- `LegacyClientExtensions` — deprecated IAsyncResult-style wrappers from the 1.x API. Do not use; all new code should use the `Async` task-based methods.
+
+**Serialization:**
+
+Uses `System.Text.Json` exclusively with two custom converters registered in `JsonExtensions.TryDeserializeObject`:
+- `DateTimeConverter` — handles the Postmark API's `" (GMT)"` date format suffix.
+- `UnicodeJsonStringConverter` — handles Unicode string encoding quirks.
+
+All models live in `src/Postmark/Model/` with subdirectories for `MessageStreams/`, `Suppressions/`, and `Webhooks/`.
+
+## Testing
+
+All tests are **integration tests** that make real HTTP calls to the Postmark API. They require API tokens configured either via a `testing_keys.json` file (searched up the directory tree from the test assembly) or environment variables.
+
+Required keys:
+```json
+{
+  "READ_SELENIUM_TEST_SERVER_TOKEN": "...",
+  "READ_LINK_TRACKING_TEST_SERVER_TOKEN": "...",
+  "READ_SELENIUM_OPEN_TRACKING_TOKEN": "...",
+  "READ_BOUNCE_TEST_SERVER_TOKEN": "...",
+  "WRITE_ACCOUNT_TOKEN": "...",
+  "WRITE_TEST_SERVER_TOKEN": "...",
+  "WRITE_TEST_SENDER_EMAIL_ADDRESS": "...",
+  "WRITE_TEST_EMAIL_RECIPIENT_ADDRESS": "...",
+  "WRITE_TEST_SENDER_SIGNATURE_PROTOTYPE": "...",
+  "BASE_URL": "https://api.postmarkapp.com"
+}
+```
+
+The config file location can be overridden with the `POSTMARK_SDK_CONFIG_FILE_NAME` environment variable.
+
+Tests that create or modify data (servers, signatures, domains) require `WRITE_*` tokens. Read-only tests use `READ_*` tokens pointing to pre-configured test servers. `ClientBaseFixture` is the abstract base class all test classes inherit from.

src/Postmark.Tests/AdminClientDomainsTests.cs

@@ -9,13 +9,13 @@ namespace Postmark.Tests
 {
     public class AdminClientDomainsTests : ClientBaseFixture, IAsyncLifetime
     {
-        private PostmarkAdminClient _adminClient;
+        private IPostmarkAdminClient _adminClient;
         private string _domainName;
         private string _returnPath;
 
         public Task InitializeAsync()
         {
-            _adminClient = new PostmarkAdminClient(WriteAccountToken, BaseUrl);
+            _adminClient = BuildAdminClient(WriteAccountToken);
             _domainName = "dotnet-lib-test.com";
             _returnPath = $"return-path.{_domainName}";
 

src/Postmark.Tests/AdminClientSenderSignatureTests.cs

@@ -11,7 +11,7 @@ namespace Postmark.Tests
 {
     public class AdminClientSenderSignatureTests : ClientBaseFixture, IAsyncLifetime
     {
-        private PostmarkAdminClient _adminClient;
+        private IPostmarkAdminClient _adminClient;
         private string _senderEmail;
         private string _replyToAddress;
         private string _senderName;
@@ -20,7 +20,7 @@ public class AdminClientSenderSignatureTests : ClientBaseFixture, IAsyncLifetime
 
         public Task InitializeAsync()
         {
-            _adminClient = new PostmarkAdminClient(WriteAccountToken, BaseUrl);
+            _adminClient = BuildAdminClient(WriteAccountToken);
             var id = Guid.NewGuid();
             _senderprefix = "test-sender-";
             _returnPath = "test." + WriteTestSenderSignaturePrototype.Split('@')[1];

src/Postmark.Tests/AdminClientServersTests.cs

@@ -11,7 +11,7 @@ namespace Postmark.Tests
 {
     public class AdminClientServersTests : ClientBaseFixture, IAsyncLifetime
     {
-        private PostmarkAdminClient _adminClient;
+        private IPostmarkAdminClient _adminClient;
         private string _serverPrefix;
         private bool? _smtpActivated;
         private string _inboundHookUrl;
@@ -29,7 +29,7 @@ public class AdminClientServersTests : ClientBaseFixture, IAsyncLifetime
 
         public Task InitializeAsync()
         {
-            _adminClient = new PostmarkAdminClient(WriteAccountToken, BaseUrl);
+            _adminClient = BuildAdminClient(WriteAccountToken);
             var id = Guid.NewGuid().ToString("n");
             _serverPrefix = "admin-client-integration-test-server-";
 

src/Postmark.Tests/ClientBaseFixture.cs

@@ -6,6 +6,7 @@
 using System.Reflection;
 using System.Linq;
 using System.Text.Json;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Postmark.Tests
 {
@@ -83,7 +84,21 @@ private static string ConfigVariable(string variableName)
         protected static readonly string WriteTestSenderSignaturePrototype = ConfigVariable("WRITE_TEST_SENDER_SIGNATURE_PROTOTYPE");
         protected static readonly string BaseUrl = ConfigVariable("BASE_URL");
 
-        protected PostmarkClient Client;
+        protected IPostmarkClient Client;
+
+        protected static IPostmarkClient BuildClient(string token)
+        {
+            var services = new ServiceCollection();
+            services.AddPostmarkClient(token);
+            return services.BuildServiceProvider().GetRequiredService<IPostmarkClient>();
+        }
+
+        protected static IPostmarkAdminClient BuildAdminClient(string token)
+        {
+            var services = new ServiceCollection();
+            services.AddPostmarkAdminClient(token);
+            return services.BuildServiceProvider().GetRequiredService<IPostmarkAdminClient>();
+        }
 
         protected ClientBaseFixture()
         {

src/Postmark.Tests/ClientBounceTests.cs

@@ -13,7 +13,7 @@ public ClientBounceTests()
             var bounceToken = !string.IsNullOrWhiteSpace(ReadBounceTestServerToken) 
                 ? ReadBounceTestServerToken 
                 : WriteTestServerToken;
-            Client = new PostmarkClient(bounceToken, BaseUrl);
+            Client = BuildClient(bounceToken);
         }
 
         [Fact]

src/Postmark.Tests/ClientMessageClickQueryTests.cs

@@ -8,7 +8,7 @@ public class ClientMessageClickQueryTests : ClientBaseFixture
     {
         public ClientMessageClickQueryTests()
         {
-            Client = new PostmarkClient(ReadLinkTrackingTestServerToken, BaseUrl);
+            Client = BuildClient(ReadLinkTrackingTestServerToken);
         }
 
         [Fact]

src/Postmark.Tests/ClientMessageOpenQueryTests.cs

@@ -8,7 +8,7 @@ public class ClientMessageOpenQueryTests : ClientBaseFixture
     {
         public ClientMessageOpenQueryTests()
         {
-            Client = new PostmarkClient(ReadSeleniumOpenTrackingToken, BaseUrl);
+            Client = BuildClient(ReadSeleniumOpenTrackingToken);
         }
 
         [Fact]

src/Postmark.Tests/ClientMessageSearchingTests.cs

@@ -8,7 +8,7 @@ public class ClientMessageSearchingTests : ClientBaseFixture
     {
         public ClientMessageSearchingTests()
         {
-            Client = new PostmarkClient(ReadSeleniumTestServerToken, BaseUrl);
+            Client = BuildClient(ReadSeleniumTestServerToken);
         }
 
         [Fact]

src/Postmark.Tests/ClientMessageStreamTests.cs

@@ -10,14 +10,14 @@ namespace Postmark.Tests
 {
     public class ClientMessageStreamTests : ClientBaseFixture, IAsyncLifetime
     {
-        private PostmarkAdminClient _adminClient;
+        private IPostmarkAdminClient _adminClient;
         private PostmarkServer _server;
 
         public async Task InitializeAsync()
         {
-            _adminClient = new PostmarkAdminClient(WriteAccountToken, BaseUrl);
+            _adminClient = BuildAdminClient(WriteAccountToken);
             _server = await _adminClient.CreateServerAsync($"integration-test-message-stream-{Guid.NewGuid()}");
-            Client = new PostmarkClient(_server.ApiTokens.First(), BaseUrl);
+            Client = BuildClient(_server.ApiTokens.First());
         }
 
         public async Task DisposeAsync()

src/Postmark.Tests/ClientSendingTests.cs

@@ -13,7 +13,7 @@ public class ClientSendingTests : ClientBaseFixture
     {
         public ClientSendingTests()
         {
-            Client = new PostmarkClient(WriteTestServerToken, BaseUrl);
+            Client = BuildClient(WriteTestServerToken);
         }
 
         [Fact]

src/Postmark.Tests/ClientServerInformationTests.cs

@@ -20,7 +20,7 @@ public class ClientServerInformationTests : ClientBaseFixture, IAsyncLifetime
 
         public Task InitializeAsync()
         {
-            Client = new PostmarkClient(WriteTestServerToken, BaseUrl);
+            Client = BuildClient(WriteTestServerToken);
             var id = Guid.NewGuid().ToString("n");
             _serverBaseName = "dotnet-integration-test-server";
 

src/Postmark.Tests/ClientStatisticsTests.cs

@@ -12,7 +12,7 @@ public class ClientStatisticsTests : ClientBaseFixture
 
         public ClientStatisticsTests()
         {
-            Client = new PostmarkClient(ReadSeleniumTestServerToken, BaseUrl);
+            Client = BuildClient(ReadSeleniumTestServerToken);
             _lastMonth = TestingDate - TimeSpan.FromDays(30);
             WindowStartDate = TestingDate - TimeSpan.FromDays(35);
         }

src/Postmark.Tests/ClientSuppressionTests.cs

@@ -11,14 +11,14 @@ namespace Postmark.Tests
 {
     public class ClientSuppressionTests : ClientBaseFixture, IAsyncLifetime
     {
-        private PostmarkAdminClient _adminClient;
+        private IPostmarkAdminClient _adminClient;
         private PostmarkServer _server;
 
         public async Task InitializeAsync()
         {
-            _adminClient = new PostmarkAdminClient(WriteAccountToken, BaseUrl);
+            _adminClient = BuildAdminClient(WriteAccountToken);
             _server = await _adminClient.CreateServerAsync($"integration-test-suppressions-{Guid.NewGuid()}");
-            Client = new PostmarkClient(_server.ApiTokens.First(), BaseUrl);
+            Client = BuildClient(_server.ApiTokens.First());
         }
 
         public async Task DisposeAsync()

src/Postmark.Tests/ClientTemplateTests.cs

@@ -15,7 +15,7 @@ public class ClientTemplateTests : ClientBaseFixture, IAsyncLifetime
 
         public Task InitializeAsync()
         {
-            Client = new PostmarkClient(WriteTestServerToken, BaseUrl);
+            Client = BuildClient(WriteTestServerToken);
             return Task.CompletedTask;
         }
 

src/Postmark.Tests/ClientTriggersTests.cs

@@ -14,7 +14,7 @@ public class ClientTriggersTests : ClientBaseFixture, IAsyncLifetime
 
         public Task InitializeAsync()
         {
-            Client = new PostmarkClient(WriteTestServerToken, BaseUrl);
+            Client = BuildClient(WriteTestServerToken);
             return Task.CompletedTask;
         }
 

src/Postmark.Tests/ClientWebhookTests.cs

@@ -12,14 +12,14 @@ namespace Postmark.Tests
 {
     public class ClientWebhookTests : ClientBaseFixture, IAsyncLifetime
     {
-        private PostmarkAdminClient _adminClient;
+        private IPostmarkAdminClient _adminClient;
         private PostmarkServer _server;
 
         public async Task InitializeAsync()
         {
-            _adminClient = new PostmarkAdminClient(WriteAccountToken, BaseUrl);
+            _adminClient = BuildAdminClient(WriteAccountToken);
             _server = await _adminClient.CreateServerAsync($"integration-test-webhooks-{Guid.NewGuid()}");
-            Client = new PostmarkClient(_server.ApiTokens.First(), BaseUrl);
+            Client = BuildClient(_server.ApiTokens.First());
         }
 
         public async Task DisposeAsync()

src/Postmark.Tests/Postmark.Tests.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
-        <TargetFramework>netcoreapp3.1</TargetFramework>
+        <TargetFramework>net10.0</TargetFramework>
         <ApplicationIcon/>
         <OutputTypeEx>library</OutputTypeEx>
         <StartupObject/>

src/Postmark.Tests/PostmarkClientTests.cs

@@ -9,7 +9,7 @@ public class PostmarkClientTests : ClientBaseFixture
     {
         public PostmarkClientTests()
         {
-            Client = new PostmarkClient(WriteTestServerToken, BaseUrl);
+            Client = BuildClient(WriteTestServerToken);
         }
 
         [Fact]

src/Postmark/IPostmarkAdminClient.cs

@@ -0,0 +1,32 @@
+using System.Threading.Tasks;
+using PostmarkDotNet.Model;
+
+namespace PostmarkDotNet
+{
+    public interface IPostmarkAdminClient
+    {
+        Task<PostmarkServer> GetServerAsync(int serverId);
+        Task<PostmarkResponse> DeleteServerAsync(int serverId);
+        Task<PostmarkServer> CreateServerAsync(string name, string color = null, bool? rawEmailEnabled = null, bool? smtpApiActivated = null, string inboundHookUrl = null, string bounceHookUrl = null, string openHookUrl = null, bool? postFirstOpenOnly = null, bool? trackOpens = null, string inboundDomain = null, int? inboundSpamThreshold = null, LinkTrackingOptions? trackLinks = null, string clickHookUrl = null, string deliveryHookUrl = null, bool? enableSmtpApiErrorHooks = null, string deliveryType = null);
+        Task<PostmarkServer> EditServerAsync(int serverId, string name = null, string color = null, bool? rawEmailEnabled = null, bool? smtpApiActivated = null, string inboundHookUrl = null, string bounceHookUrl = null, string openHookUrl = null, bool? postFirstOpenOnly = null, bool? trackOpens = null, string inboundDomain = null, int? inboundSpamThreshold = null, LinkTrackingOptions? trackLinks = null, string clickHookUrl = null, string deliveryHookUrl = null, bool? enableSmtpApiErrorHooks = null);
+        Task<PostmarkServerList> GetServersAsync(int offset = 0, int count = 100, string name = null);
+        Task<PostmarkSenderSignatureList> GetSenderSignaturesAsync(int offset = 0, int count = 100);
+        Task<PostmarkCompleteSenderSignature> GetSenderSignatureAsync(int signatureId);
+        Task<PostmarkResponse> DeleteSignatureAsync(int signatureId);
+        Task<PostmarkResponse> ResendSignatureVerificationEmailAsync(int signatureId);
+        Task<PostmarkResponse> RequestNewSignatureDKIMAsync(int signatureId);
+        Task<PostmarkCompleteSenderSignature> CreateSignatureAsync(string fromEmail, string name, string replyToEmail = null, string returnPathDomain = null, string confirmationPersonalNote = null);
+        Task<PostmarkCompleteSenderSignature> UpdateSignatureAsync(int signatureId, string name = null, string replyToEmail = null, string returnPathDomain = null, string confirmationPersonalNote = null);
+        Task<PostmarkDomainList> GetDomainsAsync(int offset = 0, int count = 100);
+        Task<PostmarkCompleteDomain> GetDomainAsync(int domainId);
+        Task<PostmarkResponse> DeleteDomainAsync(int domainId);
+        Task<PostmarkResponse> RequestNewDomainDKIMAsync(int domainId);
+        Task<PostmarkCompleteDomain> CreateDomainAsync(string name, string returnPathDomain = null);
+        Task<PostmarkCompleteDomain> UpdateDomainAsync(int domainId, string returnPathDomain);
+        Task<PostmarkCompleteDomain> VerifyDomainDkim(int domainId);
+        Task<PostmarkCompleteDomain> VerifyDomainReturnPath(int domainId);
+        Task<PostmarkDataRemoval> RequestDataRemoval(string requestedBy, string requestedFor, bool notifyWhenCompleted);
+        Task<PostmarkDataRemoval> GetDataRemovalStatus(long id);
+        Task<PostmarkCompleteSenderSignature> VerifySignatureSPF(int signatureId);
+    }
+}