commit	83d0faa2a26b7c7504d3ce94834ca76a2b33c76c	[log] [tgz]
author	Matthijs van den Bos <mvdbos@users.noreply.github.com>	Tue Apr 13 20:31:20 2021 +0200
committer	GitHub <noreply@github.com>	Tue Apr 13 21:31:20 2021 +0300
tree	aa9f4dae9dd9ac2ef5935d031cee32f25dfbb246
parent	603c85ff547dd8a31bbc5b3a5c4d23f83489d296 [diff]

tree: aa9f4dae9dd9ac2ef5935d031cee32f25dfbb246

README.md

Kotlin multiplatform / multi-format reflectionless serialization

Kotlin serialization consists of a compiler plugin, that generates visitor code for serializable classes, runtime library with core serialization API and support libraries with various serialization formats.

Supports Kotlin classes marked as @Serializable and standard collections.
Provides JSON, Protobuf, CBOR, Hocon and Properties formats.
Complete multiplatform support: JVM, JS and Native.

Introduction and references
Setup

Introduction and references

Here is a small example.

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

@Serializable 
data class Project(val name: String, val language: String)

fun main() {
    // Serializing objects
    val data = Project("kotlinx.serialization", "Kotlin")
    val string = Json.encodeToString(data)  
    println(string) // {"name":"kotlinx.serialization","language":"Kotlin"} 
    // Deserializing back into objects
    val obj = Json.decodeFromString<Project>(string)
    println(obj) // Project(name=kotlinx.serialization, language=Kotlin)
}

You can get the full code here.

Read the Kotlin Serialization Guide for all details.

You can find auto-generated documentation website on GitHub Pages.

Setup

Kotlin serialization plugin is shipped with the Kotlin compiler distribution, and the IDEA plugin is bundled into the Kotlin plugin.

Using Kotlin Serialization requires Kotlin compiler 1.4.0 or higher. Make sure you have the corresponding Kotlin plugin installed in the IDE, no additional plugins for IDE are required.

Gradle

Using the `plugins` block

You can set up the serialization plugin with the Kotlin plugin using Gradle plugins DSL:

Kotlin DSL:

plugins {
    kotlin("jvm") version "1.4.30" // or kotlin("multiplatform") or any other kotlin plugin
    kotlin("plugin.serialization") version "1.4.30"
}

Groovy DSL:

plugins {
    id 'org.jetbrains.kotlin.multiplatform' version '1.4.30'
    id 'org.jetbrains.kotlin.plugin.serialization' version '1.4.30'
}

Kotlin versions before 1.4.0 are not supported by the stable release of Kotlin serialization

Using `apply plugin` (the old way)

First, you have to add the serialization plugin to your classpath as the other compiler plugins:

Kotlin DSL:

buildscript {
    repositories { mavenCentral() }

    dependencies {
        val kotlinVersion = "1.4.30"
        classpath(kotlin("gradle-plugin", version = kotlinVersion))
        classpath(kotlin("serialization", version = kotlinVersion))
    }
}

Groovy DSL:

buildscript {
    ext.kotlin_version = '1.4.30'
    repositories { mavenCentral() }

    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-serialization:$kotlin_version"
    }
}

Then you can apply plugin (example in Groovy):

apply plugin: 'kotlin' // or 'kotlin-multiplatform' for multiplatform projects
apply plugin: 'kotlinx-serialization'

Dependency on the JSON library

After setting up the plugin one way or another, you have to add a dependency on the serialization library. Note that while the plugin has version the same as the compiler one, runtime library has different coordinates, repository and versioning.

Kotlin DSL:

repositories {
    mavenCentral()
}

dependencies {
    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.1.0")
}

Groovy DSL:

repositories {
    mavenCentral()
}

dependencies {
    implementation "org.jetbrains.kotlinx:kotlinx-serialization-json:1.1.0"
}

We also provide kotlinx-serialization-core artifact that contains all serialization API but does not have bundled serialization format with it

Android

Library should work on Android "as is". If you're using proguard, you need to add this to your proguard-rules.pro:

-keepattributes *Annotation*, InnerClasses
-dontnote kotlinx.serialization.AnnotationsKt # core serialization annotations

# kotlinx-serialization-json specific. Add this if you have java.lang.NoClassDefFoundError kotlinx.serialization.json.JsonObjectSerializer
-keepclassmembers class kotlinx.serialization.json.** {
    *** Companion;
}
-keepclasseswithmembers class kotlinx.serialization.json.** {
    kotlinx.serialization.KSerializer serializer(...);
}

# Change here com.yourcompany.yourpackage
-keep,includedescriptorclasses class com.yourcompany.yourpackage.**$$serializer { *; } # <-- change package name to your app's
-keepclassmembers class com.yourcompany.yourpackage.** { # <-- change package name to your app's
    *** Companion;
}
-keepclasseswithmembers class com.yourcompany.yourpackage.** { # <-- change package name to your app's
    kotlinx.serialization.KSerializer serializer(...);
}

You may also want to keep all custom serializers you've defined.

Multiplatform (Common, JS, Native)

Most of the modules are also available for Kotlin/JS and Kotlin/Native. You can add dependency to the required module right to the common source set:

commonMain {
    dependencies {
        // Works as common dependency as well as the platform one
        implementation "org.jetbrains.kotlinx:kotlinx-serialization-json:$serialization_version"
    }
}

The same artifact coordinates can be used to depend on platform-specific artifact in platform-specific source-set.

Maven

Ensure the proper version of Kotlin and serialization version:

<properties>
    <kotlin.version>1.4.30</kotlin.version>
    <serialization.version>1.1.0</serialization.version>
</properties>

Add serialization plugin to Kotlin compiler plugin:

<build>
    <plugins>
        <plugin>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-maven-plugin</artifactId>
            <version>${kotlin.version}</version>
            <executions>
                <execution>
                    <id>compile</id>
                    <phase>compile</phase>
                    <goals>
                        <goal>compile</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <compilerPlugins>
                    <plugin>kotlinx-serialization</plugin>
                </compilerPlugins>
            </configuration>
            <dependencies>
                <dependency>
                    <groupId>org.jetbrains.kotlin</groupId>
                    <artifactId>kotlin-maven-serialization</artifactId>
                    <version>${kotlin.version}</version>
                </dependency>
            </dependencies>
        </plugin>
    </plugins>
</build>

Add dependency on serialization runtime library:

<dependency>
    <groupId>org.jetbrains.kotlinx</groupId>
    <artifactId>kotlinx-serialization-json</artifactId>
    <version>${serialization.version}</version>
</dependency>

Kotlin multiplatform / multi-format reflectionless serialization

Table of contents

Introduction and references

Setup

Gradle

Using the plugins block

Using apply plugin (the old way)

Dependency on the JSON library

Android

Multiplatform (Common, JS, Native)

Maven

Using the `plugins` block

Using `apply plugin` (the old way)