Validate json in scala

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To validate a JSON file in Scala, you can use a JSON library that provides support for parsing and validating JSON data. One popular JSON library for Scala is "circe". Circe provides a powerful and flexible way to handle JSON data, including validating JSON files against a JSON schema. Here's an example of how you can use Circe to validate a JSON file against a JSON schema:

1. Add the Circe library as a dependency in your Scala project. You can add the following lines to your build.sbt file:

libraryDependencies += "io.circe" %% "circe-core" % "0.14.1"
libraryDependencies += "io.circe" %% "circe-parser" % "0.14.1"
libraryDependencies += "io.circe" %% "circe-generic" % "0.14.1"

2. Import the required Circe classes in your Scala code:

import io.circe._
import io.circe.parser._

3. Define your JSON schema. You can define your JSON schema as a Circe Json object or as a string that represents a valid JSON schema in JSON format. For example, let's define a simple JSON schema that validates an object with a "name" field of type string and an "age" field of type integer:

val schema: Json = Json.obj(
  "type" -> Json.fromString("object"),
  "properties" -> Json.obj(
    "name" -> Json.obj("type" -> Json.fromString("string")),
    "age" -> Json.obj("type" -> Json.fromString("integer"))
  ),
  "required" -> Json.arr(Json.fromString("name"), Json.fromString("age"))
)

4. Load and parse your JSON file:

val jsonFileContent: String = // Read your JSON file content here
val json: Either[ParsingFailure, Json] = parse(jsonFileContent)

5. Validate your JSON file against the JSON schema:

json match {
  case Right(jsonObj) =>
    val validationResult: ValidationResult = schema.validate(jsonObj)
    if (validationResult.isSuccess) {
      println("JSON is valid against the schema.")
    } else {
      println("JSON is invalid against the schema.")
      println("Validation errors: " + validationResult.left.get.toList.mkString(", "))
    }
  case Left(parseError) =>
    println("Failed to parse JSON file: " + parseError.message)
}

In this example, the schema is a Circe Json object representing the JSON schema, and json is the parsed JSON content from the JSON file. The validate method is used to validate the json against the schema. If the validation is successful, validationResult.isSuccess will be true, indicating that the JSON file is valid against the schema. If the validation fails, validationResult.left.get will contain the validation errors.

Note that Circe provides various validation options, including validating against a JSON schema, custom validation rules, and more. You can refer to the Circe documentation for more information on how to use Circe for JSON validation in Scala.