spray-json-macros

A macro library for generating spray-json JsonFormat instances. This library is highly experimental and is not production-ready. It likely still contains many sharp edges.

• Automatically create JsonFormats for case classes with more than 22 fields
• Support default parameters in static top-level case classes
• Explicitly rename fields using the @JsonProperty annotation
• Bring nested case classes into their parent objects using the @JsonUnwrapped annotation
• Automatically create JsonFormats for Scala enumerations

Installation

spray-json-macros is not currently hosted in an artifact repository. To install: clone the repository, run the package sbt task and place the resulting jar in the `/lib' folder of your project.

Usage

To enable automatic JsonFormat generation for case classes, bring the members of the AutoProductFormats into your implicit scope:

import spray.json._
import zangelo.spray.json._

object MyJsonProtocol
    extends DefaultJsonProtocol
    with AutoProductFormats

import MyJsonProtocol._

case class Person(firstName:String, lastName:String)

val person = Person("Zack", "Angelo")
val personJson = person.toJson // { "firstName": "Zack", "lastName": "Angelo" }
val personReadBack = personJson.convertTo[Person]

Annotations

The @JsonProperty annotation allows you to explicitly rename properties:

import spray.json._
import zangelo.spray.json._
import zangelo.spray.json.annotation._

object MyJsonProtocol
    extends DefaultJsonProtocol
    with AutoProductFormats

import MyJsonProtocol._

case class Person(firstName:String, @JsonProperty("surname") lastName:String)

val person = Person("Zack", "Angelo")
val personJson = person.toJson // { "firstName": "Zack", "surname": "Angelo" }
val personReadBack = personJson.convertTo[Person]

The @JsonPropertyCase annotation allows you to automatically transform the case of your properties:

import spray.json._
import zangelo.spray.json._
import zangelo.spray.json.annotation._

object MyJsonProtocol
    extends DefaultJsonProtocol
    with AutoProductFormats

import MyJsonProtocol._

@JsonPropertyCase(JsonPropertyCases.Snakize)
case class Person(firstName:String, lastName:String)

val person = Person("Zack", "Angelo")
val personJson = person.toJson // { "first_name": "Zack", "last_name": "Angelo" }
val personReadBack = personJson.convertTo[Person]

The @JsonUnwrapped annotation allows you bring nested properties their parent's JSON object:

import spray.json._
import zangelo.spray.json._
import zangelo.spray.json.annotation._

object MyJsonProtocol
    extends DefaultJsonProtocol
    with AutoProductFormats

import MyJsonProtocol._

@JsonPropertyCase(JsonPropertyCases.Capitalize)
case class Address(street:String, city:String, state:String, zip:String)

case class Person(firstName:String,
                  lastName:String,
                  @JsonUnwrapped("workAddress")
                  workAddress:Address,
                  @JsonUnwrapped("homeAddress")
                  homeAddress:Address)

val work = Address("150 Main Street", "New York", "NY", "00000")
val home = Address("600 W. Sixth", "Austin", "TX", "11111")
val person = Person("Zack", "Angelo", work, home)
val personJson = person.toJson

//  {
//      "firstName": "Zack",
//      "lastName": "Angelo",
//      "homeAddressStreet": "600 W. Sixth",
//      "homeAddressCity": "Austin",
//      "homeAddressState": "TX"
//      "homeAddressZip": "11111",
//      "workAddressStreet": "150 Main Street",
//      "workAddressCity": "New York",
//      "workAddressState": "NY",
//      "workAddressZip": "00000"
//  }

val personReadBack = personJson.convertTo[Person]