Custom Wordpress Rest API Schema Validator - Limited Cases

SchemaValidator.php

<?php
class SchemaValidator{

	public function validate_structure($params, $schema){

		$errors = array();

		foreach($schema as $key => $object){
			//check if present if required
			if(isset($object["required"]) && true == $object["required"]){
				if( !isset($params[$key]) || empty($params[$key])){
					//error and return
					$errors[$key] = "Parameter not found";
					return $errors;
				}
			}
			//If parameter is not set, then return, as it was not required Don't return in case of object
			if( ("object" != $object["type"]) &&( !isset($params[$key]) || empty($params[$key]))){
				continue;
			}

			//Now that the value is set, we need to validate it
			switch ($object["type"]) {
				case 'string':
					if(is_string($params[$key])){
						if( !isset($object['validate_callback']) || ( isset($object['validate_callback']) && call_user_func($object['validate_callback'], $params[$key], $key,""))){
							continue;
						}
						else{
							$errors[$key] = "Validation failed";
						}
					}
					else{
						$errors[$key] = "Parameter not string";
					}

					return $errors;

					break;
				case 'integer':
					if(is_int($params[$key])){
						if( !isset($object['validate_callback']) || ( isset($object['validate_callback']) && call_user_func($object['validate_callback'], $params[$key], $key,""))){
							continue;
						}
						else{
							$errors[$key] = "Validation failed";
						}
					}
					else{
						$errors[$key] = "Parameter not integer";
					}
					return $errors;

					break;
				case 'enum':
					if( isset($params[$key]) ){
						if((is_string($params[$key]) || is_int($params[$key])) && in_array($params[$key], $object["enum"])){
							continue;
						}
						else{
							$errors[$key] = "Parameter not one of: ".implode(", ",$object["enum"]);
							return $errors;
						}
					}
					break;
				case 'array':
					if(is_array($params[$key]) && count($params[$key])>0){
						$index = 0;
						foreach($params[$key] as $arr_val){
							$result = $this->validate_structure( $arr_val, array("items" => $object["items"]));
							if(count($result)>0){
								foreach($result as $k => $val){
									$result[$k] = $key."[".$index."][".$k."] ".lcfirst($result[$k]);
								}
								$errors = array_merge($errors,$result);
								return $errors;
							}
							$index++;
							continue;
						}
					}
					else if(is_array($params[$key])){
						$errors[$key] = "Array is empty";
					}
					else{
						$errors[$key] = "Parameter not of type array";
					}
					return $errors;
					break;
				case 'object':
					if(is_array($params)){

						foreach($object["properties"] as $property => $obj){
							$result = $this->validate_structure(
								array($property => $params[$property]),
								array($property => $obj)
							);
							if(is_array($result) && count($result)>0){

								$errors = array_merge($errors, $result);
								return $errors;
							}

						}
					}
					else{
						$errors[$key] = "Parameter not of type object";
					}
					return $errors;
					break;
				default:
					break;
			}


		}
		return $errors;

	}
}

Usage.php

<?php

require_once( get_template_directory() ."/inc/api/SchemaValidator.php");

$schema = array(
    'request_id' => array(
        'validate_callback' => function($param, $request, $key) {
            return is_numeric( $param );
        },
        'required' => true,
        'type' => 'integer',
        'description' => 'Your internal request id',
    ),
    'object' => array(
        'required' => true,
        'type' => 'enum',
        "enum" => array(
            "products"
        ),
        'description' => 'The object type to run the call against.',
    ),
    'total_count' => array(
        'validate_callback' => function($param, $request, $key) {
            return is_numeric( $param );
        },
        'required' => false,
        'type' => 'integer',
        'description' => 'Total count of the products',
    ),

    'data' => array(
        'type' => 'array',
        'required' => true,
        "items" => array(
            "type" => "object",
            "properties" => array(
                'action' => array(
                    'required' => true,
                    "type" => "enum",
                    "enum" => array(
                        "add", "update", "delete"
                    )
                ),
                'manufactured' => array(
                    'required' => false,
                    "type" => "enum",
                    "enum" => array(
                        "Manufactured", "Purchased", ""
                    )
                ),
            ),
        )
    )
);

$params = $request->get_json_params();

$validator = new SchemaValidator();
$errors = $validator->validate_structure($params, $this->schema);
if(is_array($errors) && count($errors)>0){
    foreach($errors as $key =>$value){
        $response = array(
                "code" => "schema_validation_failed",
                "message" => "Unable to process request because data did not pass validation tests.",
                "data" => array(
                    "field" => $key,
                    "message" => $value
                )
        );
    }
    //retun response
}