轉載請注明：TheViper http://www.cnblogs.com/TheViper/
本文將對yii中的mvc,路由器，filter,組件機制等最主要的部分進行自己的一點淺析，力求說明自己做一個php mvc不是那麼的遙不可及，其實是很簡單的。
源碼基於yii 1.13,為了方便說明，我對其進行了大量的裁剪，不過還是讓他保有上面的那些最重要的功能。裁剪下來，其實沒有幾個文件了，而且每個文件代碼最多100多行，避免因為代碼太多而懶得看。
所謂的mvc都是讓所有請求從一個地方進去，通過對請求，配置的解析，分發到對應的類方法中。
首先當然是入口文件，index.php.
1 <?php 2 $app = "app"; 3 $yii = dirname ( __FILE__ ) . '/framework/yii.php'; 4 $config = dirname ( __FILE__ ) . '/app/protected/config/main.php';//載入配置 5 require_once ($yii); 6 Yii::createWebApplication ( $config )->run ();
引入yii.php
1 <?php
2 define ( "VIEWS_DIR", "$app/protected/views/" );
3 define ( "CONTROLLERS_DIR", "$app/protected/controllers/" );
4 require(dirname(__FILE__).'/YiiBase.php');
5 class Yii extends YiiBase
6 {
7 }
原來yii是個空的類啊，去看YiiBase.
1 <?php
2 defined ( 'YII_PATH' ) or define ( 'YII_PATH', dirname ( __FILE__ ) );
3 class YiiBase {
4 public static $classMap = array ();
5 public static $enableIncludePath = true;
6 private static $_aliases = array (
7 'system' => YII_PATH
8 ); // alias => path
9 private static $_imports = array (); // alias => class name or directory
10 private static $_includePaths; // list of include paths
11 private static $_app;
12 private static $_logger;
13 public static function createWebApplication($config = null) {
14 return self::createApplication ( 'CWebApplication', $config );
15 }
16 public static function createApplication($class, $config = null) {
17 return new $class ( $config );
18 }
19 public static function app() {
20 return self::$_app;
21 }
22 //別名路徑
23 public static function getPathOfAlias($alias) {
24 if (isset ( self::$_aliases [$alias] ))
25 return self::$_aliases [$alias];
26 elseif (($pos = strpos ( $alias, '.' )) !== false) {
27 $rootAlias = substr ( $alias, 0, $pos );
28 if (isset ( self::$_aliases [$rootAlias] ))
29 return self::$_aliases [$alias] = rtrim ( self::$_aliases [$rootAlias] . DIRECTORY_SEPARATOR . str_replace ( '.', DIRECTORY_SEPARATOR, substr ( $alias, $pos + 1 ) ), '*' . DIRECTORY_SEPARATOR );
30 }
31 return false;
32 }
33 public static function setPathOfAlias($alias, $path) {
34 if (empty ( $path ))
35 unset ( self::$_aliases [$alias] );
36 else
37 self::$_aliases [$alias] = rtrim ( $path, '\\/' );
38 }
39 public static function setApplication($app) {
40 if (self::$_app === null || $app === null)
41 self::$_app = $app;
42 }
43 public static function import($alias, $forceInclude = false) {
44 if (isset ( self::$_imports [$alias] )) // previously imported
45 return self::$_imports [$alias];
46
47 if (class_exists ( $alias, false ) || interface_exists ( $alias, false ))
48 return self::$_imports [$alias] = $alias;
49 if (($pos = strrpos ( $alias, '.' )) === false) // a simple class name
50 {
51 // try to autoload the class with an autoloader if $forceInclude is true
52 if ($forceInclude && (Yii::autoload ( $alias, true ) || class_exists ( $alias, true )))
53 self::$_imports [$alias] = $alias;
54 return $alias;
55 }
56
57 $className = ( string ) substr ( $alias, $pos + 1 );
58 $isClass = $className !== '*';
59
60 if ($isClass && (class_exists ( $className, false ) || interface_exists ( $className, false )))
61 return self::$_imports [$alias] = $className;
62
63 if (($path = self::getPathOfAlias ( $alias )) !== false) {
64 if ($isClass) {
65 if ($forceInclude) {
66 if (is_file ( $path . '.php' ))
67 require ($path . '.php');
68 else
69 throw new CException ( Yii::t ( 'yii', 'Alias "{alias}" is invalid. Make sure it points to an existing PHP file and the file is readable.', array (
70 '{alias}' => $alias
71 ) ) );
72 self::$_imports [$alias] = $className;
73 } else
74 self::$classMap [$className] = $path . '.php';
75 return $className;
76 } else // a directory
77 {
78 if (self::$_includePaths === null) {
79 self::$_includePaths = array_unique ( explode ( PATH_SEPARATOR, get_include_path () ) );
80 if (($pos = array_search ( '.', self::$_includePaths, true )) !== false)
81 unset ( self::$_includePaths [$pos] );
82 }
83
84 array_unshift ( self::$_includePaths, $path );
85
86 if (self::$enableIncludePath && set_include_path ( '.' . PATH_SEPARATOR . implode ( PATH_SEPARATOR, self::$_includePaths ) ) === false)
87 self::$enableIncludePath = false;
88
89 return self::$_imports [$alias] = $path;
90 }
91 }
92 }
93 //創建組件實例
94 public static function createComponent($config) {
95 if (is_string ( $config )) {
96 $type = $config;
97 $config = array ();
98 } elseif (isset ( $config ['class'] )) {
99 $type = $config ['class'];
100 unset ( $config ['class'] );
101 }
102 if (! class_exists ( $type, false )) {
103 $type = Yii::import ( $type, true );
104 }
105 if (($n = func_num_args ()) > 1) {
106 $args = func_get_args ();
107 if ($n === 2)
108 $object = new $type ( $args [1] );
109 elseif ($n === 3)
110 $object = new $type ( $args [1], $args [2] );
111 elseif ($n === 4)
112 $object = new $type ( $args [1], $args [2], $args [3] );
113 else {
114 unset ( $args [0] );
115 $class = new ReflectionClass ( $type );
116 // Note: ReflectionClass::newInstanceArgs() is available for PHP 5.1.3+
117 // $object=$class->newInstanceArgs($args);
118 $object = call_user_func_array ( array (
119 $class,
120 'newInstance'
121 ), $args );
122 }
123 } else
124 $object = new $type ();
125 foreach ( $config as $key => $value )
126 $object->$key = $value;
127
128 return $object;
129 }
130 //按需加載相應的php
131 public static function autoload($className) {
132 include self::$_coreClasses [$className];
133 }
134 private static $_coreClasses = array (
135 'CApplication' => '/base/CApplication.php',
136 'CModule' => '/base/CModule.php',
137 'CWebApplication' => '/base/CWebApplication.php',
138 'CUrlManager' => 'CUrlManager.php',
139 'CComponent' => '/base/CComponent.php'
140 , 'CUrlRule' => 'CUrlRule.php',
141 'CController' => 'CController.php',
142 'CInlineAction' => '/actions/CInlineAction.php',
143 'CAction' => '/actions/CAction.php',
144 'CFilterChain' => '/filters/CFilterChain.php',
145 'CFilter' => '/filters/CFilter.php',
146 'CList' => '/collections/CList.php',
147 'CHttpRequest' => 'CHttpRequest.php',
148 'CDb' => 'CDb.php',
149 'CInlineFilter' => 'filters/CInlineFilter.php'
150 );
151 }
152
153 spl_autoload_register ( array (
154 'YiiBase',
155 'autoload'
156 ) );
看似很多，其實就三個地方注意下就可以了
1.spl_autoload_register,用這個就可以實現傳說中的按需加載相應的php了,坑爹啊。
2.createComponent($config)這個方法是yii組件調用的核心。在配置中注冊的所有組件都是通過它獲取組件類的實例的。比如配置：
1 <?php 2 return array ( 3 'basePath' => dirname ( __FILE__ ) . DIRECTORY_SEPARATOR . '..', 4 5 'import' => array ( 6 'application.util.*' 7 ), 8 9 'components' => array ( 10 'db' => array ( 11 'class' => 'CDb', 12 'driver' => 'mysql', 13 'hostname' => 'localhost', 14 'username' => 'root', 15 'password' => '', 16 'database' => 'youtube' 17 ), 18 'urlManager' => array ( 19 'urlFormat' => 'path', 20 'rules' => array ( 21 'comment_reply/<a:\d+>/<ci:\d+>' => 'reply/load_comment_reply', 22 'b/<id:\d+>' => array ( 23 'video/broadcast', 24 'urlSuffix' => '.html' 25 ), 26 'c/<list_start:\d+>' => 'video/list_more_video', 27 'u/reg' => 'user/reg', 28 'v/upload' => 'video/upload_video', 29 'login' => 'user/to_login', 30 'show_chanel/<chanel_id:\d+>' => 'show/chanel' , 31 'show/<show_id:\d+>' => 'show/show', 32 ) 33 ) 34 ) 35 ); 36 ?>
這個文件就返回了個map,裡面components中的db,urlManager便是我注冊的系統中的組件,裡面的array便是組件的參數.
從源碼中看到$type = $config ['class'];$object = new $type;就創建了注冊的類實例了。
3.import($alias, $forceInclude = false)。作用：導入一個類或一個目錄。導入一個類就像包含相應的類文件。 主要區別是導入一個類比較輕巧， 它僅在類文件首次引用時包含。這個也是yii的一個核心優化點。
這個在上面createComponent($config)中有用到，
if (!class_exists ( $type, false )) {
$type = Yii::import ( $type, true );
}
如果$type類沒有定義，就去導入。有些組件，核心在yii中多次create調用，這樣就保證了僅在類文件首次引用時導入。
下面分析index.php中Yii::createWebApplication ( $config )的調用過程。
這個調用是去了CWebApplication。
1 <?php
2 class CWebApplication extends CApplication {
3 public $controllerNamespace;
4 private $_controllerPath;
5 private $_viewPath;
6 private $_systemViewPath;
7 private $_controller;
8 public $controllerMap=array();
9 public function processRequest() {//開始執行請求
10 //獲取urlManager組件，解析請求，得到controller/action這種格式的string,
11 //並且將隱藏參數與請求的參數一一對應，匹配起來，寫入$_REQUEST中
12 $route = $this->getUrlManager ()->parseUrl ($this->getRequest());
13 $this->runController ( $route );
14 }
15 public function getRequest() {//獲取request組件
16 return $this->getComponent ( 'request' );
17 }
18 protected function registerCoreComponents() {//注冊核心組件
19 parent::registerCoreComponents ();
20 }
21 //執行contronller
22 public function runController($route) {
23 if (($ca = $this->createController ( $route )) !== null) {
24 list ( $controller, $actionID ) = $ca;
25 $oldController = $this->_controller;
26 $this->_controller = $controller;
27 $controller->init ();//鉤子,在執行action方法前調用，子類去實現
28 $controller->run ( $actionID );//開始轉入controller類中action方法的執行
29 $this->_controller = $oldController;
30 }
31 }
32 //創建controller類實例,從controller/action這種格式的string中解析出$controller, $actionID
33 public function createController($route, $owner = null) {
34 if ($owner === null)
35 $owner = $this;
36 if (($route = trim ( $route, '/' )) === '')
37 $route = $owner->defaultController;
38
39 $route .= '/';
40 while ( ($pos = strpos ( $route, '/' )) !== false ) {
41 $id = substr ( $route, 0, $pos );
42 if (! preg_match ( '/^\w+$/', $id ))
43 return null;
44 $id = strtolower ( $id );
45 $route = ( string ) substr ( $route, $pos + 1 );
46 if (! isset ( $basePath )) // first segment
47 {
48 $basePath = $owner->getControllerPath ();
49 $controllerID = '';
50 } else {
51 $controllerID .= '/';
52 }
53 $className = ucfirst ( $id ) . 'Controller';
54 $classFile = $basePath . DIRECTORY_SEPARATOR . $className . '.php';
55
56 if (is_file ( $classFile )) {
57 if (! class_exists ( $className, false ))
58 require ($classFile);
59 if (class_exists ( $className, false ) && is_subclass_of ( $className, 'CController' )) {
60 $id [0] = strtolower ( $id [0] );
61 return array (
62 new $className ( $controllerID . $id, $owner === $this ? null : $owner ),
63 $this->parseActionParams ( $route )
64 );
65 }
66 return null;
67 }
68 $controllerID .= $id;
69 $basePath .= DIRECTORY_SEPARATOR . $id;
70 }
71 }
72 protected function parseActionParams($pathInfo) {
73 if (($pos = strpos ( $pathInfo, '/' )) !== false) {
74 $manager = $this->getUrlManager ();//再次獲取urlManager,在上面第一次調用中已經導入。
75 $manager->parsePathInfo ( ( string ) substr ( $pathInfo, $pos + 1 ) );
76 $actionID = substr ( $pathInfo, 0, $pos );
77 return $manager->caseSensitive ? $actionID : strtolower ( $actionID );
78 } else
79 return $pathInfo;
80 }
81 public function getControllerPath() {
82 if ($this->_controllerPath !== null)
83 return $this->_controllerPath;
84 else
85 return $this->_controllerPath = $this->getBasePath () . DIRECTORY_SEPARATOR . 'controllers';
86 }
87 //兩個鉤子,子類去實現
88 public function beforeControllerAction($controller, $action) {
89 return true;
90 }
91 public function afterControllerAction($controller, $action) {
92 }
93 protected function init() {
94 parent::init ();
95 }
96 }
沒有構造方法，構造方法在父類CApplication裡面。
1 <?php
2 abstract class CApplication extends CModule {
3 private $_id;
4 private $_basePath;
5 abstract public function processRequest();
6 public function __construct($config = null) {
7 if (is_string ( $config ))
8 $config = require ($config);
9 Yii::setApplication ( $this );//保存整個app實例
10 if (isset ( $config ['basePath'] )) {
11 $this->setBasePath ( $config ['basePath'] );
12 unset ( $config ['basePath'] );
13 } else
14 $this->setBasePath ( 'protected' );
15 //設置別名,後面就可以用application表示basePath了
16 Yii::setPathOfAlias ( 'application', $this->getBasePath () );
17 //鉤子，模塊 預 初始化時執行，子類實現。不過這時，配置還沒有寫入框架
18 $this->preinit ();
19 $this->registerCoreComponents ();
20 //父類實現
21 $this->configure ( $config );
22 //加載靜態應用組件
23 $this->preloadComponents ();
24 //這才開始初始化模塊
25 $this->init ();
26 }
27 protected function registerCoreComponents() {
28 $components = array (
29 'request' => array (
30 'class' => 'CHttpRequest'
31 ),
32 'urlManager' => array (
33 'class' => 'CUrlManager'
34 )
35 );
36
37 $this->setComponents ( $components );//父類實現
38 }
39 public function run() {
40 $this->processRequest ();
41 }
42 public function getId() {
43 if ($this->_id !== null)
44 return $this->_id;
45 else
46 return $this->_id = sprintf ( '%x', crc32 ( $this->getBasePath () . $this->name ) );
47 }
48 public function setId($id) {
49 $this->_id = $id;
50 }
51 public function getBasePath() {
52 return $this->_basePath;
53 }
54 public function setBasePath($path) {
55 if (($this->_basePath = realpath ( $path )) === false || ! is_dir ( $this->_basePath ))
56 return;
57 }
58 public function getDb() {
59 return $this->getComponent ( 'db' );//父類實現
60 }
61 public function getUrlManager() {
62 return $this->getComponent ( 'urlManager' );
63 }
64 public function getController() {
65 return null;
66 }
67 public function getBaseUrl($absolute = false) {
68 return $this->getRequest ()->getBaseUrl ( $absolute );
69 }
70 }
__construct裡面注釋寫的很詳細了，值得注意的是registerCoreComponents ()。前面說了那麼多，那麼Yii::createWebApplication ( $config )到底是做什麼的。
其實最終目的對這個裁剪過的yii而言就是注冊核心組件。就這麼簡單.
setComponents ( $components )在父類CModule裡面.
1 <?php
2 abstract class CModule extends CComponent {
3 public $preload = array ();
4 public $behaviors = array ();
5 private $_id;
6 private $_parentModule;
7 private $_basePath;
8 private $_modulePath;
9 private $_params;
10 private $_modules = array ();
11 private $_moduleConfig = array ();
12 private $_components = array ();
13 private $_componentConfig = array ();
14 //重寫是為了方便直接用 application.組件 這種方式直接獲取組件
15 public function __get($name) {
16 if ($this->hasComponent ( $name ))
17 return $this->getComponent ( $name );
18 else
19 return parent::__get ( $name );
20 }
21 public function __isset($name) {
22 if ($this->hasComponent ( $name ))
23 return $this->getComponent ( $name ) !== null;
24 else
25 return parent::__isset ( $name );
26 }
27 public function hasComponent($id) {
28 return isset ( $this->_components [$id] ) || isset ( $this->_componentConfig [$id] );
29 }
30 //
31 public function getComponent($id, $createIfNull = true) {
32 if (isset ( $this->_components [$id] ))
33 return $this->_components [$id];
34 else if (isset ( $this->_componentConfig [$id] ) && $createIfNull) {
35 $config = $this->_componentConfig [$id];
36 $component = Yii::createComponent ( $config );//YiiBase,返回組件實例
37 $component->init ();//鉤子，調用子類重寫的init方法
38 //將組件寫入數組保存，並返回
39 return $this->_components [$id] = $component;
40 }
41 }
42 public function setComponent($id, $component, $merge = true) {
43 //組件寫入數組保存
44 if (isset ( $this->_componentConfig [$id] ) && $merge) {
45
46 $this->_componentConfig [$id] = self::mergeArray ( $this->_componentConfig [$id], $component );
47 } else {
48
49 $this->_componentConfig [$id] = $component;
50 }
51 }
52 public static function mergeArray($a, $b) {
53 $args = func_get_args ();
54 $res = array_shift ( $args );
55 while ( ! empty ( $args ) ) {
56 $next = array_shift ( $args );
57 foreach ( $next as $k => $v ) {
58 if (is_integer ( $k ))
59 isset ( $res [$k] ) ? $res [] = $v : $res [$k] = $v;
60 elseif (is_array ( $v ) && isset ( $res [$k] ) && is_array ( $res [$k] ))
61 $res [$k] = self::mergeArray ( $res [$k], $v );
62 else
63 $res [$k] = $v;
64 }
65 }
66 return $res;
67 }
68 public function setComponents($components, $merge = true) {
69 foreach ( $components as $id => $component )
70 $this->setComponent ( $id, $component, $merge );
71 }
72 //子類CApplication調用，用來為模塊指定配置
73 public function configure($config) {
74 if (is_array ( $config )) {
75 foreach ( $config as $key => $value )
76 $this->$key = $value;
77 }
78 }
79 protected function preloadComponents() {
80 foreach ( $this->preload as $id )
81 $this->getComponent ( $id );
82 }
83 //又是兩個鉤子
84 protected function preinit() {
85 }
86 protected function init() {
87 }
88 }
看到所謂的注冊組件就是寫入數組保存，getComponent()的時候就是用前面講到的YiiBase裡面的createComponent($config)返回組件實例。就這麼簡單。
而CApplication裡面的什麼getDb()，getUrlManager()也是在調用getComponent()。
