I'm having trouble deserializing a JSON object whi...

# serialization

[v79]

I'm having trouble deserializing a JSON object which contains a base64 encoded string. Given the following class:

@Serializable
class ImageDTO(val srcKey: String, val contentType: String, val bytes: String)

I get the following error:

Could not deserialize body. Error is: Invalid symbol ':'(72) at index 4

The source JSON object looks like this:

{"srcKey":"piCture.jpg","contentType":"image/jpeg","bytes":"data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD.......

So it looks like deserialization is being tripped up by the "bytes":"data:image..." part. Any suggestions? Perhaps I shouldn't be trying to upload images as a base64-encoded string?

[Adam S]

What version of Kotlin/Kotlinx Serialization are you using?

This works for me:

import kotlinx.serialization.*
import kotlinx.serialization.json.*

fun main() {
  val data = """
    {"srcKey":"piCture.jpg","contentType":"image/jpeg","bytes":"data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD"}
  """.trimIndent()


  val i: ImageDTO = Json.decodeFromString(data)

  println(i)
}

@Serializable
data class ImageDTO(val srcKey: String, val contentType: String, val bytes: String)

ImageDTO(srcKey=piCture.jpg, contentType=image/jpeg, bytes=data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD)

[v79]

Kotlin 1.9.20, serialization 1.9.0, serialization-json 1.5.0. I'll look for more information.

[v79]

It's an IllegalArgumentException.

[v79]

If a hand-code the base64 string, without data:image/jpeg;base64, then the deserialization actually works.

[v79]

Bother. Works in unit tests, fails in production. The best kind of bug!

[v79]

I clearly need better error reporting; the error was not in deserialization, it was in the Base64 decode later on.