CodeIgniter源代码阅读（五）Hooks.php-白红宇

CodeIgniter源代码阅读（五）Hooks.php

阅读量：6231 次

发布时间：2019-06-21

本文共 6602 字，大约阅读时间需要 22 分钟。

1 <?php

if ( !

defined('BASEPATH'))

exit('No direct script access allowed');

* CodeIgniter

* An open source application development framework for PHP 5.1.6 or newer

* @package CodeIgniter

* @author ExpressionEngine Dev Team

* @license http://codeigniter.com/user_guide/license.html

* @link http://codeigniter.com

* @since Version 1.0

* @filesource

根据配置(application/config/hooks.php)中的特定配置来调用函数

// ------------------------------------------------------------------------

//调用

* CodeIgniter Hooks Class

* Provides a mechanism to extend the base system without hacking.

* @package CodeIgniter

* @subpackage Libraries

* @category Libraries

* @author ExpressionEngine Dev Team

* @link http://codeigniter.com/user_guide/libraries/encryption.html

class CI_Hooks {

* Determines wether hooks are enabled

* @var bool

var

$enabled =

FALSE;

开启hook的标志，默认是关闭的。APPPATH/config/config.php中的配置也是默认关闭的，如果想使用hook，要在config.php中开启。

* List of all hooks set in config/hooks.php

* @var array

var

$hooks =

array();

//在_initialize()函数初始化的过程中将APPPATH/config/hook.php中定义的hook数组，引用到$this->hooks;

* Determines wether hook is in progress, used to prevent infinte loops

* @var bool

var

$in_progress =

FALSE;

当一个hook执行的时候，会给标记 $in_process = TRUE ，是为了防止同一个hook被同时调用。

* Constructor

function __construct()

58 {

$this->_initialize();

60 log_message('debug', "Hooks Class Initialized");

61 }

--------------------------------------------------------------------

* Initialize the Hooks Preferences

* @access private

* @return void

初始化hook

function _initialize()

73 {

$CFG =& load_class('Config', 'core');

获取配置文件

// If hooks are not enabled in the config file

// there is nothing else to do

//如果配置文件中设置了是不允许hooks，则直接返回退出本函数。

if (

$CFG->item('enable_hooks') ==

FALSE)

//判断config.php中是否开启hook

{

return;

81 }

Grab the "hooks" definition file.

// If there are no hooks, we're done.

//要使用到的钩子，必须在配置目录下的hooks.php里面定义好。否则无法使用。

if (

defined('ENVIRONMENT') AND

is_file(APPPATH.'config/'.ENVIRONMENT.'/hooks.php'))

87 {

include(APPPATH.'config/'.ENVIRONMENT.'/hooks.php');

89 }

elseif (

is_file(APPPATH.'config/hooks.php'))

91 {

include(APPPATH.'config/hooks.php');

93 }

if ( !

isset(

$hook) OR !

is_array(

$hook))

97 {

return;

99 }

100

101

$this->hooks =&

$hook;

include（hook.php），将文件里定义的hook数组引用到$this->hooks

102

$this->enabled =

TRUE;

103 }

104

105

--------------------------------------------------------------------

106

107

108

* Call Hook

109

* 外部其实就是调用这个_call_hook函数进行调用钩子程序。而此方法中再调用_run_hook去执行相应的钩子

110

* Calls a particular hook

111

112

* @access private

113

* @param string the hook name

114

* @return mixed

115

116

function _call_hook(

$which = '')

117 {

118

if ( !

$this->enabled OR !

isset(

$this->hooks[

$which]))

//以pre_system挂钩点为例，当调用_call_hook('pre_system')时

119

{

120

return

FALSE;

//确保$this->enable = TRUE && 定义了$this->hooks['pre_system']

121

}

122

//如果是二维数组就遍历，依次_run_hook($this->hooks['pre_system'][$val])

123

if (

isset(

$this->hooks[

$which][0]) AND

is_array(

$this->hooks[

$which][0]))

124 {

125

foreach (

$this->hooks[

$which]

$val)

126 {

127

$this->_run_hook(

$val);

128 }

129 }

130

else

如果是一维数组，那么直接_run_hook($this->hooks['pre_system']) //同一个位置可以执行多个hook

131

{

132

$this->_run_hook(

$this->hooks[

$which]);

133 }

134

135

return

TRUE;

136 }

137

138

--------------------------------------------------------------------

139

140

141

* Run Hook 取得 hook.php中配置并组装成对应的类函数参数类执行

142

143

* Runs a particular hook

144

145

* @access private

146

* @param array the hook details

147

* @return bool

148

149

function _run_hook(

$data)

150 {

151

if ( !

is_array(

$data))

$data 是传递过来的hook数组

152

{

153

return

FALSE;

154 }

155

$data 就是我们在APPPATH/config/hook.php 定义的hook数组

156

//$hook['pre_controller'] = array(

157

// 'class' => 'MyClass',

158

// 'function' => 'Myfunction',

159

// 'filename' => 'Myclass.php',

160

// 'filepath' => 'hooks',

161

// 'params' => array('beer', 'wine', 'snacks')

162

// );

163

164

// -----------------------------------

165

// Safety - Prevents run-away loops

166

// -----------------------------------

167

168

// If the script being called happens to have the same

169

// hook call within it a loop can happen

170

171

if (

$this->in_progress ==

TRUE)

172 {

173

return;

174 }

175

176

-----------------------------------

177

// Set file path

178

// -----------------------------------

179

180

if ( !

isset(

$data['filepath']) OR !

isset(

$data['filename']))

181 {

182

return

FALSE;

183 }

184

185

$filepath = APPPATH.

$data['filepath'].'/'.

$data['filename'];

186

187

if ( !

file_exists(

$filepath))

188 {

189

return

FALSE;

190 }

191

192

-----------------------------------

193

// Set class/function name

194

// -----------------------------------

195

196

197

* 取出data里面的数据，加载 APPPATH.$data['filepath'].$data['filename'];

198

实例化钩子类，调用function。应用到示例中就是

199

$this->in_process = TRUE;

200

$Hook = new MyClass();

201

$Hook->Myfunction($params);

202

$this->in_process = FALSE;

203

204

205

$class =

FALSE;

206

$function =

FALSE;

207

$params = '';

208

209

if (

isset(

$data['class']) AND

$data['class'] != '')

210 {

211

$class =

$data['class'];

212 }

213

214

if (

isset(

$data['function']))

215 {

216

$function =

$data['function'];

217 }

218

219

if (

isset(

$data['params']))

220 {

221

$params =

$data['params'];

222 }

223

224

if (

$class ===

FALSE AND

$function ===

FALSE)

225 {

226

return

FALSE;

227 }

228

229

-----------------------------------

230

// Set the in_progress flag

231

// -----------------------------------

232

233

$this->in_progress =

TRUE;

234

235

-----------------------------------

236

// Call the requested class and/or function

237

// -----------------------------------

238

239

if (

$class !==

FALSE)

240 {

241

if ( !

class_exists(

$class))

242 {

243

require(

$filepath);

244 }

245

246

$HOOK =

new

$class;

247

$HOOK->

$function(

$params);

248 }

249

else

250 {

251

if ( !

function_exists(

$function))

252 {

253

require(

$filepath);

254 }

255

256

$function(

$params);

257 }

258

259

$this->in_progress =

FALSE;

260

return

TRUE;

261 }

262

263 }

264

265

END CI_Hooks class

266

267

End of file Hooks.php

268

Location: ./system/core/Hooks.php

转载于:https://www.cnblogs.com/gongchang/archive/2012/11/20/2778636.html

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