Scala library for IO functionality

General Scala IO functionality such as JSON schema validation

Project built with the following (main) technologies:

• Scala

• SBT

• Json4s

Introduction

TODO

Build and Deploy

The project is built with SBT. On a Mac (sorry everyone else) do:

brew install sbt

It is also a good idea to install Typesafe Activator (which sits on top of SBT) for when you need to create new projects - it also has some SBT extras, so running an application with Activator instead of SBT can be useful. On Mac do:

brew install typesafe-activator

To compile:

sbt compile

or

activator compile

To run the specs:

sbt test

To run integration specs:

sbt it:test

Publishing

To publish the jar to artifactory you will need to

1. Copy the .credentials file into your /.ivy2/
2. Edit this .credentials file to fill in the artifactory security credentials (amend the realm name and host where necessary)

sbt publish

Note that initially this project refers to some libraries held within a private Artifactory. However, those libraries have been open sourced under https://github.com/UKHomeOffice.

Example Usage

• Validate JSON against a JSON schema:

  val json: JValue = getYourJson()
  val schema: JValue = getYourSchema()

  val Right(result) = JsonSchema(schema).validate(json) // Assuming successful validation

• Transform JSON from one structure to another:

  val yourJsonTransformer = new JsonTransformer {
    def transform(json: JValue): JValue Or JsonError = {
      val JsonTransformation(oldJson, newJson) = (
        map("name" -> "superName") ~
        mapArray("fee" -> "payment.feeInPence", field => JInt(BigInt(field.extract[String])))
      )(json)

      Right(newJson)
    }
  }

  val flatJson = parse("""
  {
    "name": "Batman",
    "fee_1": "12",
    "fee_2": "15",
    "fee_3": 18
  }""")

  val json = parse("""
  {
    "superName": "Batman",
    "payment": [
      { "feeInPence": 12 },
      { "feeInPence": 15 },
      { "feeInPence": 18 }
    ]
  }""")

  // Assuming successful transformation
  transform(flatJson) mustEqual Right(json)

Note - if required (though not advised) the EmptyJsonSchema can be used to all JSON to be validated successfully.

JSON Schema Validation

There are several online JSON schema validation tools such as JSON Schema Validator

Alternatively, a JSON schema can be validated from the Scala REPL by doing the following:

sbt

console

import uk.gov.homeoffice.json._

import uk.gov.homeoffice.json.Json._

jsonFromFilepath("src/test/resources/schema-test.json") map { JsonSchema(_) }

If you've given a valid file path and the schema is valid, the result will be something like:

res3: scala.util.Try[uk.gov.homeoffice.json.JsonSchema] = Success(uk.gov.homeoffice.json.JsonSchema@7568db95)