README

Here we define an interface for Validators as well as an Abstract class from which concrete objects that validate data based on field names can be built. The goal: to standardize the way that Dash creates validators in their work.

Installation

composer require dashifen/validator

Usage

You can either extend the AbstractValidator object or simply implement the AbstractInterface on your own. The interface defines two methods:

1. canValidate - returns a Boolean value to tell the calling scope if data can be validated based on a $field parameter.
2. isValid - returns a Boolean regarding the validity of a $value based on its $field label.

The AbstractValidator implements both of these for you while requiring that you define a third method: a protected getValidationMethod method. It returns the name of another method that is assumed to be of the same object that can validate data labeled by $field.

Example

In this example, we're assuming that the naming convention for the application's fields is to use kebab-case.

class Validator extends AbstractValidator {
    protected function getValidationMethod(string $field): string {
      
        // to convert a kebab-case $field to a function name, we want to 
        // convert it to StudlyCaps.  so, first, we convert from kebab-case to 
        // camelCase and then we ucfirst() the camelCase string to make it 
        // studly.  finally, we add the word "validate."  Thus, a start-date
        // field becomes startDate, then StartDate, and finally we return 
        // transformStartDate.
  
        $camelCase = preg_replace_callback("/-([a-z])/", function (array $matches): string {
            return strtoupper($matches[1]);
        }, $field);
      
        return "validate" . ucfirst($camelCase);
    }

    private function validateStartDate(string $date): bool {
      
        // what we want to do is make sure that our date appears valid.
        // we're less concerned with format (a transform can standardize 
        // that).  here, we just want to know that what we have might be
        // a date which is a good job for strtotime()!
  
        return strtotime($date) !== false;
    }
}

The above little class represents a simple, concrete object based on the functionality of the AbstractValidator found within this repo. The abstract object's implementation of the canValidate and isValid methods of our interface make sure that we use the getValidationMethod to identify the name of a method that can transform data labeled by $field and then will call that method when we need it returning its result.