Support configurable JsonSerializerOptions

src/Camunda.Worker/Client/ExternalTaskClient.cs

@@ -34,6 +34,13 @@ public ExternalTaskClient(HttpClient httpClient)
             });
     }
 
+    public ExternalTaskClient(HttpClient httpClient, Action<JsonSerializerOptions> configureJsonOptions)
+        : this(httpClient)
+    {
+        _jsonSerializerOptions = _jsonSerializerOptions
+            .Also(configureJsonOptions);
+    }
+
     [ExcludeFromCodeCoverage]
     private static void ValidateHttpClient(HttpClient httpClient)
     {

src/Camunda.Worker/Client/Serialization/JsonVariableJsonConverter.cs

@@ -23,7 +23,7 @@ public class JsonVariableJsonConverter : JsonConverter<JsonVariable>
     public override void Write(Utf8JsonWriter writer, JsonVariable value, JsonSerializerOptions options)
     {
         writer.WriteStartObject();
-        writer.WriteString("value", value.Value.ToJsonString());
+        writer.WriteString("value", value.Value.ToJsonString(options));
         writer.WriteEndObject();
     }
 }

src/Camunda.Worker/Client/ServiceCollectionExtensions.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Net.Http;
+using System.Text.Json;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace Camunda.Worker.Client;
@@ -8,11 +9,18 @@ public static class ServiceCollectionExtensions
 {
     public static IHttpClientBuilder AddExternalTaskClient(this IServiceCollection services)
     {
-        return services.AddHttpClient<IExternalTaskClient, ExternalTaskClient>();
+        return services.AddHttpClient<IExternalTaskClient, ExternalTaskClient>(
+            httpClient => new ExternalTaskClient(httpClient));
     }
 
     public static IHttpClientBuilder AddExternalTaskClient(this IServiceCollection services, Action<HttpClient> configureClient)
     {
-        return services.AddHttpClient<IExternalTaskClient, ExternalTaskClient>(configureClient);
+        return AddExternalTaskClient(services).ConfigureHttpClient(configureClient);
+    }
+
+    public static IHttpClientBuilder AddExternalTaskClient(this IServiceCollection services, Action<HttpClient> configureClient, Action<JsonSerializerOptions> configureJsonOptions)
+    {
+        return services.AddHttpClient<IExternalTaskClient, ExternalTaskClient>(
+            httpClient => new ExternalTaskClient(httpClient, configureJsonOptions)).ConfigureHttpClient(configureClient);
     }
 }

test/Camunda.Worker.Tests/Client/ExternalTaskClientTest.cs

@@ -3,6 +3,7 @@
 using System.Net;
 using System.Net.Http;
 using System.Text;
+using System.Text.Encodings.Web;
 using System.Threading;
 using System.Threading.Tasks;
 using Camunda.Worker.Variables;
@@ -14,16 +15,17 @@ namespace Camunda.Worker.Client;
 public class ExternalTaskClientTest : IDisposable
 {
     private readonly MockHttpMessageHandler _handlerMock = new();
-    private readonly ExternalTaskClient _client;
+    private ExternalTaskClient _client;
+    private HttpClient _httpClient;
 
     public ExternalTaskClientTest()
     {
-        _client = new ExternalTaskClient(
-            new HttpClient(_handlerMock)
-            {
-                BaseAddress = new Uri("http://test/api")
-            }
-        );
+        _httpClient = new HttpClient(_handlerMock)
+        {
+            BaseAddress = new Uri("http://test/api")
+        };
+
+        _client = new ExternalTaskClient(_httpClient);
     }
 
     public void Dispose()
@@ -94,6 +96,40 @@ public async Task TestComplete()
         _handlerMock.VerifyNoOutstandingExpectation();
     }
 
+    [Fact]
+    public async Task TestCompleteWithCustomJsonOptions()
+    {
+        _client = new ExternalTaskClient(_httpClient, opt =>
+        {
+            opt.Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping;
+        });
+
+        var entity = new
+        {
+            Description = "The \"Спутник-1\" satellite"
+        };
+
+        var requestContent = @"{""workerId"":""testWorker"",""variables"":{""TEST"":{""value"":" +
+            @"""{\""Description\"":\""The \\\""Спутник-1\\\"" satellite\""}""," +
+            @"""type"":""Json""}},""localVariables"":null}";
+
+        _handlerMock.Expect(HttpMethod.Post, "http://test/api/external-task/testTask/complete")
+            .WithContent(requestContent)
+            .Respond(HttpStatusCode.NoContent);
+
+        var request = new CompleteRequest("testWorker")
+        {
+            Variables = new Dictionary<string, VariableBase>
+            {
+                ["TEST"] = JsonVariable.Create(entity)
+            }
+        };
+
+        await _client.CompleteAsync("testTask", request, CancellationToken.None);
+
+        _handlerMock.VerifyNoOutstandingExpectation();
+    }
+
     [Fact]
     public async Task TestReportFailure()
     {