SValidator

A library for validation and data binding of scala objects in a fluent and concise manner.

This project is heavily inspired by the FluentValidation library for .NET and licensed under the MIT license.

An additional library is provided for easy integration with the Play! framework.

Installation

SValidator is published to Maven Central for Scala 3. Add the following to your build.sbt:

libraryDependencies += "com.magaran" %% "svalidator" % "0.1.0"

Quick Usage

Consider the following case class.

case class Person(firstName: String,
                  lastName: String,
                  age: Int,
                  married: Boolean,
                  hasJob: Boolean,
                  notes: Option[String])

SimpleValidator style

Create a class that inherits from com.magaran.svalidator.validation.simple.SimpleValidator[A] where A is the type of the object you want to validate. Then define rules with WithRules and the fluent rule builders.

import com.magaran.svalidator.validation.simple.SimpleValidator

class PersonValidator extends SimpleValidator[Person] {

  override def validate(using instance: Person) = WithRules(

    For(_.firstName) ForField "firstName"
      must (_.nonEmpty) withMessage "First name is required"
      must (_.length <= 32) withMessage "Must have 32 characters or less",

    For(_.lastName) ForField "lastName"
      must (_.nonEmpty) withMessage "Last name is required"
      must (_.length <= 32) withMessage "Must have 32 characters or less",

    For(_.age) ForField "age"
      must (_ >= 0) withMessage "Must be a positive number",

    For(_.married) ForField "married"
      must (_ == false) when (_.age < 18) withMessage "Must be 18 years or older to allow marking marriage",

    For(_.hasJob) ForField "hasJob"
      must (_ == false) when (_.age < 21) withMessage "Must be 21 years or older to allow marking a job"
  )
}

To perform the actual validation, create an instance of your validator class and call validate passing in the instance to validate.

val validator = new PersonValidator
val summary = validator.validate(using instance)

FunctionalValidator style

For cases where validation depends on additional input data or implicit context, use the functional style. Extend FunctionalValidator (or one of its aliases) and return Either[Invalid, SuccessData].

import com.magaran.svalidator.validation.Invalid
import com.magaran.svalidator.validation.functional.FunctionalValidator

// Example input/context types
case class RegistrationData(emailAlreadyExists: Boolean)
case class RequestContext(isAdmin: Boolean)

class PersonFunctionalValidator
  extends FunctionalValidator[Person, RegistrationData, RequestContext, Unit] {

  override def validate(instance: Person, inputData: RegistrationData)(using ctx: RequestContext)
      : Either[Invalid, Unit] =
    WhenValidating(instance)
      .withSuccessData(())
      .withRules(
        For(_.age) ForField "age"
          must (_ >= 0) withMessage "Must be a positive number",
        For(_.firstName) ForField "firstName"
          must (_.nonEmpty) withMessage "First name is required"
      )
}

To execute:

val validator = new PersonFunctionalValidator
val result = validator.validate(person, RegistrationData(emailAlreadyExists = false))(using RequestContext(false))

Check the wiki for more details: Basic Usage