Still needs to be improved...

MenuService.php

<?php

namespace DeltaX\Crud\MenuService;

use DeltaX\ContentAccess\ContentAccessInterface;

/**
 * MenuService
 */

abstract class MenuService {


	/**
	 * Set of permissions
	 * @var array
	 */

	protected $permissions;


	/**
	 * Response: The main content 
	 * of the response body
	 * @var mixed
	 */

	protected $outputData;


	/**
	 * Response: The Status Code
	 * @var int
	 */

	protected $code = 0;


	/**
	 * Response: The Success Indicator
	 * @var bool
	 */

	protected $success = false;


	/**
	 * Response: Response Message
	 * @var string
	 */

	protected $message;


	/**
	 * Request: inputData taken from forms
	 * or JSON request body
	 * @var array
	 */

	protected $inputData;

	/**
	 * An object to authenticate an authorized user
	 * @var DeltaX\ContentAccess\ContentAccessInterface;
	 */

	protected $authenticator;

	/**
	 * An object to validate input for queries 
	 * @var \DeltaX\Crud\ModelService\ValidatorInterface $validator
	 */

	protected $validator;

	/**
	 * Only this method, validate(), and 
	 * authenticate() set the following 
	 * properties: $success, $code, 
	 * $message, and $outputData.
	 *
	 * Any response bodies resulted 
	 * from database queries are done here
	 *
	 * If there are required input data,
	 * use $inputData property  
	 * 
	 * @return array
	 */
	abstract protected function runCommand();

	/**
	 * runQuery
	 * @return self
	 */
	protected function processQuery(){
		
		if($this->code !== 0){
			return $this;
		}

		$this->runQuery();
		return $this;
	}

	/**
	 * setInput
	 * @param array $input
	 * @return self
	 */
	public function setInput(array $input) {
		$this->inputData = $input;
		return $this;
	}

	/**
	 * setAuthenticator
	 * @param \DeltaX\ContentAccess\ContentAccessInterface $authenticator
	 * @return self
	 */
	public function setAuthenticator(ContentAccessInterface $authenticator) {
		$this->authenticator = $authenticator;
		return $this;

	}

	/**
	 * setAuthenticator
	 * @param \DeltaX\Crud\ModelService\ValidatorInterface $validator
	 * @return self
	 */
	public function setValidator(ValidatorInterface $validator) {
		$this->validator = $validator;
		return $this;
	}

	/**
	 * authenticate
	 * @return self
	 */
	protected function authenticate() {

		if($this->code !== 0){
			return $this;
		}

		if ( ! $this->authenticator->authorize($this->permissions)){
			$this->code = 401;
			$this->message = 'User is not authorized to do action on content';
		}

		return $this;
	}

	/**
	 * validate
	 * @return self
	 */
	protected function validate() {

		if($this->code !== 0){
			return $this;
		}

		//If validate() yields 'true', all inputs are valid
		$validation = $this->validator->validate($this->inputData);

		//If validate() returns an array, it means that there are errors
		if (is_array($validation)) {
			$this->code = 400;
			$this->message = 'Some inputs are not valid';
			$this->outputData = $validation;
		}

		return $this;
	}

	/**
	 * prepareResponse
	 * @return array
	 */
	protected function prepareResponse() {
		return [
			'success' => $this->success,
			'code' => $this->code,
			'message' => $this->message,
			'data' => $this->outputData
		];
	}

	/**
	 * execute
	 * @return mixed
	 */
	public function execute() {
		return $this->authenticate()
			->validate()
			->prepareInput()
			->runQuery()
			->prepareResponse();
	}

}