PHP $_POST Validator

<?php
/**
 * Form Validation class
 *
 * @package default
 * @author Deac Karns
 **/
class FormValidator
{
  protected $validation = true;
  protected $required = [];
  protected $post = null;

  protected $error_bag = [
      "code"=>null
    , "error"=>""
    , "errors"=>[]
  ];

  function __construct($check, $die = true)
  {
    $this->setRequired($check);
    $this->getInput();
    $this->getFiles();
    $this->checkRequired();
    $this->generateResponse($die);
  }

  public function log(){
    error_log(print_r($this,true));
  }

  private function getFiles(){
    foreach ($_FILES as $key => $file) {
      $this->post['files'][$key] = $file;
    }
  }

  private function getInput(){
    $post = file_get_contents('php://input');
    
    $result = [];
    mb_parse_str($post, $result);
    
    if(empty($result)){
      $result = $_POST;
    }
    
    $this->post = $result;
    return $result;
  }

  private function checkRequired(){
    if(count($this->required)){
      foreach ($this->required as $key) {
        
        switch ($key['test']) {
          case 'empty':
            if(empty($this->post[$key['key']])){
              $this->error_bag['error'] = "Missing Required Parameters";
              $this->error_bag['code'] = 400;
              $this->validation = false;
              $this->error_bag['errors'][$key['key']] = $key['key'].' can not be empty';
            }
            break;
          
          case 'count':
            if(count($this->post[$key['key']]) < 1){
              $this->error_bag['error'] = "Missing Required Parameters";
              $this->error_bag['code'] = 400;
              $this->validation = false;
              $this->error_bag['errors'][$key['key']] = $key['key'].' must have at least one record';
            }
            break;

          case 'email':
            if(!filter_var($this->post[$key['key']], FILTER_VALIDATE_EMAIL)){
              $this->error_bag['error'] = "Missing Required Parameters";
              $this->error_bag['code'] = 400;
              $this->validation = false;
              $this->error_bag['errors'][$key['key']] = '('.$this->post[$key['key']].') must be a valid email address';
            }
            break;

          case 'file':
            if(!array_key_exists($key['key'], $this->post['files'])){
              $subtext = (isset($key['sub']))? " of type {$key['sub']}" : "";
              $this->error_bag['error'] = "Missing Required Parameters";
              $this->error_bag['code'] = 400;
              $this->validation = false;
              $this->error_bag['errors'][$key['key']] = "Must be a file$subtext";
            }
            if(array_key_exists($key['key'], $this->post['files']) && isset($key['sub'])){
              $type = $this->post['files'][$key['key']]['type'];
              if(strpos($type, $key['sub']) === FALSE){
                $this->error_bag['error'] = "Missing Required Parameters";
                $this->error_bag['code'] = 400;
                $this->validation = false;
                $this->error_bag['errors'][$key['key']] = "Must be a file of type {$key['sub']}";
              }
            }
            break;
        }

      }
    }
  }

  private function setRequired($required){
    $check = [];
    foreach ($required as $requirement) {
      $sub = explode(':', $requirement);
      $org = explode('|', $sub[0]);
      $test['test'] = (count($org) == 1)? 'empty' : $org[1];
      $test['key'] = $org[0];
      if(isset($sub[1])){
        $test['sub'] = $sub[1];
      }
      $check[] = $test;
    }
    $this->required = $check;
  }

  private function generateResponse($die){
    if(!$this->validation && $die){
      http_response_code(400);
      header('Content-Type: application/json');
      $this->error_bag['post'] = $this->post;
      echo json_encode($this->error_bag);
      die();
    }else{
      return $this;
    }
  }
}

// Example useage
/*
require('FormValidator.php');

$emailForm = new FormValidator([
      'first_name'
    , 'last_name|empty'
    , 'email|email'
    , 'logo|file:image/jpeg'
]);
*/

$emailForm->log();

Deac,

I would suggest commenting out line 149 and on line 132 it is causing a parseerror when trying to send back the 200 response. With further inspection it wasn't being passed as a json object. echo json_encode($this); fixed it.

Also, on line 81 it should be $this->error_bag['errors'][$key['key']] = $key['key'].' must be a valid email address';