⚠️ Archived in favor of a future project (agcom/kbson) ⚠️

Bson serialization

Bson serialization format implementation for Kotlinx serialization, based on The BSON library (org.mongodb.bson).

JVM only.

Also, provides useful tools to integrate with MongoDB Java driver. For example, the out of box SerializationCodecRegistry.

Setup

Currently, only supports Kotlinx serialization runtime 0.20.0.

Gradle

• *.gradle:

  repositories {
      jcenter() // Make sure jcenter is added to your project repositories
  }
  
  dependencies {
      implementation 'com.github.agcom.bson:bson-serialization:0.5.0' // The bson serialization library
      implementation 'com.github.agcom.bson:bson-mongodb:0.5.0' // MongoDB driver extensions
  }

• *.gradle.kts: Same as *.gradle, with some small tweaks.

Usage

Here is a small example,

import kotlinx.serialization.*
import com.github.agcom.bson.serialization.*
import org.bson.*

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

val bson = Bson()

fun main() {
    val data = Project("com.github.agcom.bson", "Kotlin")
    
    // Serializing
    val bsonValue = bson.toBson(Project.serializer(), data) // A `BsonValue` child, in this case a `BsonDocument`
    println(bsonValue) // {"name": "com.github.agcom.bson", "language": "Kotlin"}
    
    // Deserializing
    println(
        bson.fromBson(Project.serializer(), bsonValue)
    ) // Project(name=com.github.agcom.bson, language=Kotlin)
}

Serialization functions

The following functions can be found in the com.github.agcom.bson.serialization.Bson class.

• toBson and fromBson: The above example ☝️.

• dump and load:

  import kotlinx.serialization.*
  import com.github.agcom.bson.serialization.*
  import org.bson.*
  
  @Serializable
  data class Project(val name: String, val language: String)
  
  val bson = Bson()
  
  fun main() {
      val data = Project("com.github.agcom.bson", "Kotlin")
  
      // Dump
      val bytes = bson.dump(Project.serializer(), data)
  
      // Load
      println(
          bson.load(Project.serializer(), bytes)
      ) // Project(name=com.github.agcom.bson, language=Kotlin)
  }

  Doesn't support loading/dumping primitive types.

Serializers

Various bson types adapter serializers can be found under com.github.agcom.bson.serialization.serializers package.

Those are all registered as default contextual serializers, so you can use @ContextualSerializer safely.

For example, BsonValueSerializer, TemporalSerializer and RegexSerializer.

MongoDB driver extensions

Provides extensions to integrate with MongoDB Java driver.

• Serialization codec

  An adapter between KSerializer and Codec.

   import kotlinx.serialization.*
   import com.github.agcom.bson.serialization.*
   import org.bson.codecs.Codec
   import com.github.agcom.bson.mongodb.codecs.*
   
   @Serializable
   data class Project(val name: String, val language: String)
   
   val bson = Bson()
   
   fun main() {
       val codec: Codec<Project> serializer= SerializationCodec(bson, Project.serializer()) // Look here
       ...
   }

• Serialization codec registry

  An adapter between Bson and CodecRegistry.

  import kotlinx.serialization.*
  import com.github.agcom.bson.serialization.*
  import com.github.agcom.bson.mongodb.codecs.*
  import org.bson.codecs.configuration.*
  import com.mongodb.MongoClientSettings
  
  @Serializable
  data class Project(val name: String, val language: String)
  
  val bson = Bson()
  
  fun main() {
      // Composing two registries
  	val registry: CodecRegistry = CodecRegistries.fromRegistries(
          MongoClientSettings.getDefaultCodecRegistry(), // The driver's default codec registry
    		SerializationCodecRegistry(bson) // Serialization registry
  	)
      ...
  }

  It's recommended to compose the serialization registry after the default registry. This reduces hip-hops (better performance) when working with simple bson types.