Chapter 11. Using the AMQ Streams Kafka Bridge

API request and response bodies are always encoded as JSON.

You set the embedded data format when creating a consumer using the consumers/groupid endpoint—​for more information, see the next section.

The embedded data format is the format of the Kafka messages that are transmitted, over HTTP, from a producer to a consumer using the Kafka Bridge. Two embedded data formats are supported: JSON and binary.

When creating a consumer using the /consumers/groupid endpoint, the POST request body must specify an embedded data format of either JSON or binary. This is specified in the format field, for example:

{
  "name": "my-consumer",
  "format": "binary", 1
...
}

The embedded data format specified when creating a consumer must match the data format of the Kafka messages it will consume.

If you choose to specify a binary embedded data format, subsequent producer requests must provide the binary data in the request body as Base64-encoded strings. For example, when sending messages by making POST requests to the /topics/topicname endpoint, the value must be encoded in Base64:

{
  "records": [
    {
      "key": "my-key",
      "value": "ZWR3YXJkdGhldGhyZWVsZWdnZWRjYXQ="
    },
  ]
}

Producer requests must also provide a Content-Type header that corresponds to the embedded data format, for example, Content-Type: application/vnd.kafka.binary.v2+json.

After creating a consumer, subsequent GET requests must provide an Accept header in the following format:

Accept: application/vnd.kafka.embedded-data-format.v2+json

Where the embedded-data-format is the embedded data format of the consumer: either json or binary.

For example, when retrieving records for a subscribed consumer using an embedded data format of JSON, include this Accept header:

Accept: application/vnd.kafka.json.v2+json