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Advanced Usage

While typical usage is covered in Usage, Confluent Schema Registry also provides functionality for more advanced usage.

Get latest schema id by subject​

const subject = 'com.example.Simple'
const id = await registry.getLatestSchemaId(subject)

Get schema id by subject and version​

const subject = 'com.example.Simple'
const version = 1

const id = await registry.getRegistryId(subject, version)

Note: Currently there is no way to list versions by subject.

Get schema id by schema​

Returns the schema id if the schema has already been registered for the provided subject.

If a matching schema does not exist for the subject, it throws a ConfluentSchemaRegistryError

const subject = 'com.example.Simple'
const schema = await avdlToAVSCAsync('path/to/protocol.avdl')

const id = await registry.getRegistryIdBySchema(subject, {
  type: SchemaType.AVRO,
  schema: JSON.stringify(schema),
})

Getting schema by schema id​

Normally Confluent Schema Registry keeps the schemas internally and don't require the user to handle them to encode/decode data, but if you need to get a schema from the registry, you can do so by its schema id:

// See https://github.com/kafkajs/confluent-schema-registry/blob/master/src/%40types.ts#L30-L46
// for a complete return type
const schema = await registry.getSchema(id)

Using custom middlewares​

The Schema Registry Client now supports adding custom mappersmith middlewares, providing flexibility to handle various use cases such as OAuth authentication or other custom request/response transformations.

To use custom middlewares, include them when initializing the Schema Registry Client:

import { Middleware } from 'mappersmith'

const customMiddleware: Middleware = jest.fn(() => {
  return {
    async request(request) {
      return request.enhance({
        headers: {
          Authorization: 'Bearer Random',
        },
      })
    },
    async response(next) {
      return next()
    },
  }
})

const registry = new SchemaRegistry({
  host: 'your_host',
  middlewares: [customMiddleware],
})