Micronaut - Bind Get parameter object in Controller

Question

I am implementing a Controller with a GET endpoint that is ought to receive the following request: /mycontroller?myDate=2019-05-01

My data class looks like this

data class MyData(
   val myDate: LocalDate
)

And my controller:

@Controller
class MyController {

  @Get("{?mydata*}")
  fun getMyEndpoint(mydata: MyData)...

}

Micronaut only binds the request in case I provide a default constructor for MyData, thus make myDate nullable or provide a default value - neither of those is what I wish to do.

Is there a way to get this working without providing the default constructor? Jackson e.g. can also handle it.

Thanks :)

Answer 1

Full working example:

import io.micronaut.core.convert.ConversionContext
import io.micronaut.core.convert.TypeConverter
import io.micronaut.http.annotation.Controller
import io.micronaut.http.annotation.Get
import java.time.LocalDate
import java.util.*
import javax.inject.Singleton

@Controller("/base")
class MyController {

   @Get("/path")
   fun getMyEndpoint(myData: MyData) {
      println("MyData: $myData")
   }

}

data class MyData(
   val myDate: LocalDate
)

@Singleton
class MyDataConverter : TypeConverter<String, MyData> {
   override fun convert(obj: String, targetType: Class<MyData>, context: ConversionContext?): Optional<MyData> =
      Optional.of(MyData(myDate = LocalDate.parse(obj)))
}

• Make a call to your server (e.g. if it running on port 8080):
  • http://localhost:8080/base/path?myData=2019-01-01
• You will see the output in the console of the server.

Pro tip: if you are using Jackson and Kotlin don't forget to include the jackson-module-kotlin dependency:

compile "com.fasterxml.jackson.module:jackson-module-kotlin:$YourJacksonVersionHere"