Debugging

With CBOR being a binary format debugging problems can sometimes be a bit more difficult than with text-based formats like JSON, which are immediately human-readable.

In order to help debug problems with encoding or decoding, independently of whether they are caused by your own application code or invalid / unexpected input, you can easily switch on logging of the encoding or decoding process with the .withPrintLogging() modifier.

For example, this snippet:

copysourceimport io.bullet.borer.Cbor
import io.bullet.borer.Codec.ForEither.default

val value = Map(
  "foo" -> Left(42),
  "bar" -> Right(Vector("For", "the", "King!"))
)
val encoded = Cbor.encode(value).toByteArray
val decoded =
  Cbor
    .decode(encoded)
    .withPrintLogging() // just insert this line to enable logging
    .to[Map[String, Either[Int, Vector[String]]]]
    .value

produces this logging output to the console:

1: {
    1/2: "foo"
    1/2: -> {
        1/1: 0
        1/1: -> 42
    1/2: }
    2/2: "bar"
    2/2: -> {
        1/1: 1
        1/1: -> [
            1/3: "For"
            2/3: "the"
            3/3: "King!"
        1/1: ]
    2/2: }
1: }
2: END

which makes it very easy to see, what exactly the decoding input consists of.
Also, in case of any exception the log will break off exactly at the point where the exception got thrown, which is often a great help in locating the problem.