大家知道CodeIgniter框架式MVC分層的,通常大家把業務邏輯寫到Controller中,而Model只負責和數據庫打交道。
但是隨着業務越來越複雜,controller越來越臃腫,舉一個簡單的例子,比如說用戶下訂單,這必然會有一系列的操作:更新購物車、添加訂單記錄、會員添加積分等等,且下訂單的過程可能在多種場景出現,如果這樣的代碼放controller中則很臃腫難以複用,如果放model會讓持久層和業務層耦合。現在公司的項目就是,很多人將一些業務邏輯寫到model中去了,model中又調其它model,也就是業務層和持久層相互耦合。這是極其不合理的,會讓model難以維護,且方法難以複用。
是不是可以考慮在controller和model中加一個業務層service,由它來負責業務邏輯,封裝好的調用接口可以被controller複用。
這樣各層的任務就明確了:
Model(DAO):數據持久層的工作,對數據庫的操作都封裝在這。
Service : 業務邏輯層,負責業務模塊的邏輯應用設計,controller中就可以調用service的接口實現業務邏輯處理,提高了通用的業務邏輯的複用性,設計到具體業務實現會調用Model的接口。
Controller :控制層,負責具體業務流程控制,這裏調用service層,將數據返回到視圖
View : 負責前端頁面展示,與Controller緊密聯繫。
基於上面描述,實現過程:
(1)讓CI能夠加載service,service目錄放在application下,因爲CI系統沒有service,則在application/core下新建擴展MY_Service.php
- <?php
-
- class MY_Service
- {
- public function __construct()
- {
- log_message('debug', "Service
Class Initialized");
- }
- function __get($key)
- {
- $CI = & get_instance();
- return $CI->$key;
- }
- }
(2)擴展CI_Loader實現,加載service,在application/core下新建MY_Loader.php文件:
- <?php
-
- class MY_Loader extends CI_Loader
- {
- /**
- * List of loaded sercices
- *
- * @var array
- * @access protected
- */
- protected $_ci_services = array();
- /**
- * List of paths to load sercices from
- *
- * @var array
- * @access protected
- */
- protected $_ci_service_paths
= array();
- /**
- * Constructor
- *
- * Set the path to the Service files
- */
- public function __construct()
- {
- parent::__construct();
- load_class('Service','core');
- $this->_ci_service_paths = array(APPPATH);
- }
- /**
- * Service Loader
- *
- * This function lets users load and instantiate classes.
- * It is designed to be called from a user's app controllers.
- *
- * @param string the name of the class
- * @param mixed the optional parameters
- * @param string an optional object name
- * @return void
- */
- public function service($service = '', $params = NULL, $object_name = NULL)
- {
- if(is_array($service))
- {
- foreach($service as $class)
- {
- $this->service($class, $params);
- }
- return;
- }
- if($service == '' or isset($this->_ci_services[$service])) {
- return FALSE;
- }
- if(! is_null($params) && ! is_array($params)) {
- $params = NULL;
- }
- $subdir = '';
-
- // Is the service in a sub-folder? If so, parse out the filename and path.
- if (($last_slash = strrpos($service, '/')) !== FALSE)
- {
- // The path is in front of the last slash
- $subdir = substr($service, 0, $last_slash + 1);
-
- // And the service name behind it
- $service = substr($service, $last_slash + 1);
- }
- foreach($this->_ci_service_paths as $path)
- {
- $filepath = $path .'service/'.$subdir.$service.'.php';
- if ( ! file_exists($filepath))
- {
- continue;
- }
- include_once($filepath);
- $service = strtolower($service);
-
- if (empty($object_name))
- {
- $object_name = $service;
- }
- $service = ucfirst($service);
- $CI = &get_instance();
- if($params !== NULL)
- {
- $CI->$object_name = new $service($params);
- }
- else
- {
- $CI->$object_name = new $service();
- }
- $this->_ci_services[] = $object_name;
- return;
- }
- }
- }
(3)簡單例子實現:
控制器中調用service :
- <?php
-
- class User extends CI_Controller
- {
- public function __construct()
- {
- parent::__construct();
- $this->load->service('user_service');
- }
- public function login()
- {
- $name = 'phpddt.com';
- $psw = 'password';
- print_r($this->user_service->login($name, $psw));
- }
- }
service中調用model :
- <?php
-
- class User_service extends MY_Service
- {
- public function __construct()
- {
- parent::__construct();
- $this->load->model('user_model');
- }
- public function login($name, $password)
- {
- $user = $this->user_model->get_user_by_where($name, $password);
- //.....
- //.....
- //.....
- return $user;
- }
- }
model中你只跟db打交道:
- <?php
-
- class User_model extends CI_Model
- {
- public function __construct()
- {
- parent::__construct();
- }
- public function get_user_by_where($name, $password)
- {
- //$this->db
- //......
- //......
- return array('id' => 1, 'name' => 'mckee');
- }
- }
-