Sending a message through Kafka - Value serializer not specified and there is no default serializer defined for type

My first attempt to send a typed message through Kafka resulted in the following error message:

Value cannot be null. (Parameter 'Value serializer not specified and there is no default serializer defined for type PageViewEvent)

Here is the code I was using:

	// Create a producer that can be used to send messages to kafka that have no key and a value of type PageViewEvent
	using var producer = new ProducerBuilder<Null, PageViewEvent>(config)
	.Build();
	//Construct a message to send (generic type must match what was used above when creating the producer)
	var message = new Message<Null, PageViewEvent>
	{
	Value = new PageViewEvent{ pageUrl=$"http://kafkaexample/{value}"}
	};
	await producer.ProduceAsync("kafka-topic-name", message) ;

view raw PublishTypedMessageToKafka.cs hosted with ❤ by GitHub

As the error message mentions, you need to explicitly specify what serializer should be used for your message object. Therefore you need to use the SchemaRegistryClient and specify a serializer(I’m using Avro in the sample below):

	var schemaRegistryConfig = new SchemaRegistryConfig
	{
	Url = "localhost:8081"
	};
	using var schemaRegistry = new CachedSchemaRegistryClient(schemaRegistryConfig);
	// Create a producer that can be used to send messages to kafka that have no key and a value of type PageViewEvent
	using var producer = new ProducerBuilder<Null, PageViewEvent>(config)
	.SetValueSerializer(new AvroSerializer<PageViewEvent>(schemaRegistry))
	.Build();

view raw SetMessageSerializer.cs hosted with ❤ by GitHub