Can't locate companion serializer for class class List about kotlinx.serialization HOT 21 CLOSED

this one working:
val map = mapOf(1 to "1", 2 to "2")
val serial = (IntSerializer to StringSerializer).map
val s = JSON.unquoted.stringify(serial, map)
assertEquals("{1:1,2:2}",s)
but not this:
val map23 = mapOf(1 to mapOf(3 to "4"), 2 to mapOf(4 to "5"))
val serial = (IntSerializer to StringSerializer).map
val s = JSON.stringify(serial, map23)

is it possible to serialize nested maps?

from kotlinx.serialization.

For root-level collections you must specify serializers explicitly: #27

from kotlinx.serialization.

I see, maybe this should be stated in the documentation somewhere?

from kotlinx.serialization.

@sandwwraith Just for reference can you provide an example?
In particular I'm trying to work with a map and I'm not sure from which Pair to get the map property. So far I couldn't find any example to illustrate this use case.

from kotlinx.serialization.

@flaghacker it was recently added: 9f19871#diff-04c6e90faac2675aa89e2176d2eec7d8R75

from kotlinx.serialization.

@jivimberg You should use .map function on Pair<KeySerializer, ValueSerializer>. For @Serializable marked types serializer is companion object, and for built-ins you can use IntSerializer, etc from internal package

from kotlinx.serialization.

Hmm I still don't really get what I'm supposed to do. An edaptation of @elizarov's (proposed) example in #27 doesn't compile:

val list = JSON.parse("""{"foo": "Hello World!"""", Foo.list)

And I'm looking to go the other way around, serializing an object.

from kotlinx.serialization.

seems like arguments just messed up: KSerializer goes first argument in function, so you need JSON.stringify(Foo.list, """[{"foo": "bar"}]""")

You can find more examples in tests: https://github.com/Kotlin/kotlinx.serialization/blob/master/runtime/common/src/test/kotlin/kotlinx/serialization/CustomSerializersTest.kt#L88

from kotlinx.serialization.

Hmm, with that exact code the gradle build fails with:

Type inference failed: Cannot infer type parameter T in fun <T> stringify(saver: KSerialSaver<T>, obj: T): String
None of the following substitutions
(KSerialSaver<String>,String)
(KSerialSaver<List<Foo>>,List<Foo>)
can be applied to
(KSerializer<List<Foo>>,String)

Also Foo.list is an unresolved reference according to Idea, is that normal?

from kotlinx.serialization.

Sorry, of course .stringify should have List<Foo> as second argument - it's serializing; and .parse should have string as second argument to get back List<Foo>

Yes, that's normal because regular Kotlin plugin don't know about synthetic objects. We will release small additional plugin soon.

from kotlinx.serialization.

Hmm the signature of .stringify: fun <T> stringify(saver: KSerialSaver<T>, obj: T): String, so it looks like Foo.list has to go in the first place after all? Maybe I had to specify the type argument explicitly?

I can't reproduce my issue from yesterday anymore, now gradle build also complains: "Unresolved reference: list", still your exact code. My build.gradle: (should be the same as yesterday really)

buildscript {
    ext.kotlin_version = "1.1.51"

    ext.kotlinx_html_version = "0.6.4"
    ext.kotlinx_serialization_version = "0.2"

    ext.kotlin_src = "src/"

    ext.web_dir = "web"
    ext.build_dir = "build/kotlin/main"

    repositories {
        mavenCentral()
        jcenter()

        maven { url "https://plugins.gradle.org/m2/" }
        maven { url "https://kotlin.bintray.com/kotlinx" }
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath "org.jetbrains.kotlinx:kotlinx-gradle-serialization-plugin:$kotlinx_serialization_version"
    }
}

apply plugin: "kotlin2js"
apply plugin: "kotlin-dce-js"
apply plugin: "kotlinx-serialization"

repositories {
    mavenCentral()
    jcenter()

    maven { url "http://dl.bintray.com/kotlin/kotlin-eap-1.1" }
    maven { url "https://kotlin.bintray.com/kotlinx" }
}

dependencies {
    compile "org.jetbrains.kotlin:kotlin-stdlib-js:$kotlin_version"
    compile "org.jetbrains.kotlinx:kotlinx-html-js:$kotlinx_html_version"
    compile "org.jetbrains.kotlinx:kotlinx-serialization-runtime-js:$kotlinx_serialization_version"
}

sourceSets {
    main.kotlin.srcDirs = [kotlin_src]
}

compileKotlin2Js {
    kotlinOptions.moduleKind = "plain"
    kotlinOptions.outputFile = "${build_dir}/main.js"

    kotlinOptions.sourceMap = true
    kotlinOptions.sourceMapEmbedSources = "always"
}

task copyJsBuildFiles(type: Copy) {
    dependsOn runDceKotlinJs

    from "${build_dir}/min"
    into web_dir
}

task web {
    dependsOn copyJsBuildFiles
}

I'm sorry for the messy situation.

from kotlinx.serialization.

You build file looks OK, can you provide some example code?

from kotlinx.serialization.

import kotlinx.serialization.json.JSON

fun main(args: Array<String>) {
    val list = listOf(Foo("a"), Foo("b"))
    println(JSON.stringify(Foo.list, """[{"foo": "bar"}]"""))
}

@Serializable
data class Foo(val foo: String?)

Is my full code right now.

from kotlinx.serialization.

You've just mixed up JSON methods:

val list = listOf(Foo("a"), Foo("b"))
println(JSON.stringify(Foo.list, list))

will print serialized list, and

println(JSON.parse(Foo.list,  """[{"foo": "bar"}]"""))

will print deserialized list

from kotlinx.serialization.

Yes, @coolemza , it's possible, but you need to specify a nested serializer too:
val serial = (IntSerializer to (IntSerializer to StringSerializer).map).map

I suggest you to wrap this structure in a @Serializable class to let the compiler plugin build serializer for you

from kotlinx.serialization.

Do you have an example of how to get it right with Map? I have been desperately trying all possible combinations with or without generics, can't get it working:

JSON.parse(Pair.map, message)
JSON.parse(Pair<String, Int>.map, message)
JSON.parse<Map<String, Int>>(Pair.map, message)
...

from kotlinx.serialization.

@pmiklos you need to call .map extension function on instance of Pair<KSerializer<K>, KSerializer<V>> to get KSerializer<Map<K,V>>. So serializer for your example would be Pair(StringSerializer, IntSerializer).map. IntSerializer and etc located in the kotlinx.serialization.internal package

from kotlinx.serialization.

Thanks, that works indeed. I just realized that StringSerializer and IntSerializer are objects and not classes...

from kotlinx.serialization.

Most of use-cases described here are now mentioned in documentation.

Feel free to open new issues if you have some problems.

from kotlinx.serialization.

is it possible to serialize nested maps of dynamic unknown depth?

from kotlinx.serialization.

@IARI There is nothing in the architecture that prevents the dynamic unknown depth. If it works for depth 2 it works for depth 10 it works for depth 50. (There are practical limits due to JVM stack size)

from kotlinx.serialization.