fluent_validator

Rule based Fluent Validation API that can be used with your entities. You not only are able to use built-in validators but also create your own validators and write extensions on ValidatorBuilder to use it effectively.

Usage

Create a validator by extending Validator base class with the type of the class that you want to validate. You can chain the rules. Here is an example of a simple usage:

class TestClass {
  const TestClass(this.prop1);

  final String prop1;
}

class TestValidator extends Validator<TestClass> {
  TestValidator() {
    rulesFor('Prop1', (TestClass testClass) => testClass.prop1).emailAddress();
  }
}

With this simple configuration now you can validate your class:

 final testValidator = TestValidator();
 final testClass = TestClass();

 final validationResult = testValidator.validate(testClass);

ValidationResult will return with the errors which are encountered while validating the entity.

Complex Class Validation

Sometimes you may wish to validate complex classes that doesn't have primitives but other classes as props. You can use setValidator method to register the validator for the prop

class TestClass {
  const TestClass(this.prop1);

  final String prop1;
}

class TestValidator extends Validator<TestClass> {
  TestValidator() {
    rulesFor('Prop1', (TestClass testClass) => testClass.prop1).emailAddress();
  }
}


class ComplexClass {
    const ComplexClass(this.testClass);

    final TestClass testClass;
}

class ComplexClassValidator extends Validator<ComplexClass> {
    ComplexClassValidator() {
        rulesFor('TestClass', (ComplexClass compClass) => compClass.testClass).setValidator(TestValidator());
    }
}

Custom Validators

The one can create custom validators for his/her demands. In order to achieve this:

• Create your own rule.
• Add an extension method on ValidatorBuilder.

class FooRule extends Rule {
  FooRule(String message) : super(message);

  @override
  bool isValid(dynamic value) {
    if (value is String) {
      return _isValidFoo(value);
    }
    throw UnimplementedError();
  }

  bool _isValidFoo(String value) {
    // do your logic and return bool
    return toBeOrNotToBe;
  }
}

extension MyValidators on ValidatorBuilder {
  ValidatorBuilder notEmpty() {
    setRule(FooRule('Value should be valid foo'));
    return this;
  }
}

Credits

Inspired by Fluent Validation.