StockPurchaseController.kt

package me.stefanozanella.sampleapp

import com.sksamuel.avro4k.Avro
import org.apache.avro.generic.GenericRecord
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.kafka.core.KafkaTemplate
import org.springframework.stereotype.Controller
import org.springframework.ui.Model
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.ModelAttribute
import org.springframework.web.bind.annotation.PostMapping

@Controller
class StockPurchaseController {
  @Autowired
  lateinit var kafka: KafkaTemplate<String, GenericRecord> // <-- (1)

  @GetMapping("/")
  fun newStockPurchase(model: Model): String {
    model.addAttribute("stockPurchase", StockPurchase())

    return "addStockPurchase"
  }

  @PostMapping("/stock_purchase")
  fun addStockPurchase(@ModelAttribute stockPurchase: StockPurchase): String {
    val avroRecord = Avro.default.toRecord(StockPurchase.serializer(), stockPurchase) // <-- (2)

    kafka.send(
      "stock-purchases",
      stockPurchase.ticker,
      avroRecord // <-- (3)
    )

    return "stockPurchaseCreated"
  }
}