fix: Observe JsonSerializer options for JsonEventFormatter using Newtonsoft.Json

This is the Json.NET equivalent of #225.

Note that not every option in JsonTextWriter is supported; in the future we could potentially introduce some alternative approach to provide more flexibility.

Signed-off-by: Jon Skeet <[email protected]>

Author: jskeet

src/CloudNative.CloudEvents.NewtonsoftJson/JsonEventFormatter.cs

@@ -389,7 +389,7 @@ public override ReadOnlyMemory<byte> EncodeStructuredModeMessage(CloudEvent clou
             };
 
             var stream = new MemoryStream();
-            var writer = new JsonTextWriter(new StreamWriter(stream));
+            var writer = CreateJsonTextWriter(stream);
             WriteCloudEventForBatchOrStructuredMode(writer, cloudEvent);
             writer.Flush();
             return stream.ToArray();
@@ -406,7 +406,7 @@ public override ReadOnlyMemory<byte> EncodeBatchModeMessage(IEnumerable<CloudEve
             };
 
             var stream = new MemoryStream();
-            var writer = new JsonTextWriter(new StreamWriter(stream));
+            var writer = CreateJsonTextWriter(stream);
             writer.WriteStartArray();
             foreach (var cloudEvent in cloudEvents)
             {
@@ -417,6 +417,20 @@ public override ReadOnlyMemory<byte> EncodeBatchModeMessage(IEnumerable<CloudEve
             return stream.ToArray();
         }
 
+        private JsonTextWriter CreateJsonTextWriter(Stream stream) =>
+            // TODO: Allow settings to be specified separately?
+            // JsonSerializer doesn't allow us to set the indentation or indentation character, for example.
+            new JsonTextWriter(new StreamWriter(stream))
+            {
+                Formatting = Serializer.Formatting,
+                DateFormatHandling = Serializer.DateFormatHandling,
+                DateFormatString = Serializer.DateFormatString,
+                DateTimeZoneHandling = Serializer.DateTimeZoneHandling,
+                FloatFormatHandling = Serializer.FloatFormatHandling,
+                Culture = Serializer.Culture,
+                StringEscapeHandling = Serializer.StringEscapeHandling,
+            };
+
         private void WriteCloudEventForBatchOrStructuredMode(JsonWriter writer, CloudEvent cloudEvent)
         {
             Validation.CheckCloudEventArgument(cloudEvent, nameof(cloudEvent));

test/CloudNative.CloudEvents.UnitTests/NewtonsoftJson/JsonEventFormatterTest.cs

@@ -1080,6 +1080,18 @@ public void DecodeStructured_DefaultContentTypeToApplicationJson()
             Assert.Equal("some text", jsonData.Value);
         }
 
+        [Fact]
+        public void EncodeStructured_IndentationSettings()
+        {
+            var cloudEvent = new CloudEvent().PopulateRequiredAttributes();
+            var formatter = new JsonEventFormatter(new JsonSerializer { Formatting = Formatting.Indented });
+            var encoded = formatter.EncodeStructuredModeMessage(cloudEvent, out _);
+            // Normalize the result to LF line endings.
+            var json = BinaryDataUtilities.GetString(encoded, Encoding.UTF8).Replace("\r\n", "\n").Replace("\r", "\n");
+            var expected = "{\n  \"specversion\": \"1.0\",\n  \"id\": \"test-id\",\n  \"source\": \"//test\",\n  \"type\": \"test-type\"\n}";
+            Assert.Equal(expected, json);
+        }
+
         // Utility methods
         private static object? DecodeBinaryModeEventData(byte[] bytes, string contentType)
         {