I have a issue about LENS. when I use `Map<Str...

# http4k

[King River Lee]

I have a issue about LENS. when I use Map<String, Any?>> as input json, to get map from req. it parse json number 5 to java.math.BigIntger rather than <http://kotlin.Int|kotlin.Int>. any one knows why? or How can I fix it?

[King River Lee]

{"number" : 5} parse to mapof("number" to 5). the 5 in kotlin map is a java.math.BigIntger

[King River Lee]

here is my code and debug info

[Andrew O'Hara]

JSON doesn't really have type information, and most marshallers can barely differentiate between integers and decimals. There's no way for the marshaller to know the maximum size of the number, so my best guess is that it chose the safest option, which is BigInteger.

You wouldn't want it to return an Int one time, and then a Long another time, would you?

[King River Lee]

Ok, I see. so I need to handle the BigIntger myself. got it.

[s4nchez]

If you're using Jackson, that can be configured centrally (i.e. you don't have to handle BigIntegers yourself). Here's an example:

import com.fasterxml.jackson.databind.DeserializationFeature
import com.fasterxml.jackson.module.kotlin.KotlinModule
import org.http4k.format.ConfigurableJackson
import org.http4k.format.asConfigurable

data class Foo(val bar: Int)

object CustomJackson : ConfigurableJackson(
    KotlinModule.Builder().build()
        .asConfigurable()
        .done()
        .configure(DeserializationFeature.USE_BIG_INTEGER_FOR_INTS, false)
)

fun main() {
    val jsonExample = """{"bar":123}"""

    val foo = CustomJackson.asA<Foo>(jsonExample)
    println(foo)
}

[s4nchez]

This will automatically serialise to Int rather than BigInteger 😉

[s4nchez]

@King River Lee The default config for Jackson in http4k is to use BigInteger/BigDecimals, but that can be customised if you're confident that the values you'll receive fit in an Int 😉