浅析Wordpress的插件执行流程

王朝other·作者佚名  2008-12-18
窄屏简体版  字體: |||超大  

1、首先,我现在pugins文件夹下写一个自己的插件

复制PHP内容到剪贴板

PHP代码:

<?php

/*

Plugin Name: test

Plugin URI: http://wordpress.org/#

Description: 我测试用的

Author: lw(fantasy)

Version: 0.1

Author URI: http://www.xxx.com/

*/

$test = "<div id='my_test'>这是我的第一个插件!</div>";

function output(){

global $test;

echo $test;

}

add_action('wp_footer','output');

?>

然后在后台启用。。

2、WP执行是加载在”wp-settings.php”,而在此文件中,可以找到以下与插件相关的代码片断:

复制PHP内容到剪贴板

PHP代码:

if ( get_option('active_plugins') ) {

$current_plugins = get_option('active_plugins');

dump($current_plugins);

if ( is_array($current_plugins) ) {

foreach ($current_plugins as $plugin) {

if ( '' != $plugin && 0 == validate_file($plugin) && file_exists(WP_PLUGIN_DIR . '/' . $plugin) )

include_once(WP_PLUGIN_DIR . '/' . $plugin);

}

}

}

我dump了一下$current_plugins,得到

Array

(

[0] => Fanfou-Daily/Fanfou-Daily.php

[1] => mulberrykit.php

[2] => test.php

)

可以看到我写的test.php插件已经被include进去了。。

3、在主题模板里的footer.php里面会执行一个函数

<?php wp_footer(); ?>

而这个wp_footer里面又执行

do_action('wp_footer');

而这个do_action就是执行前面我们已经注册了的【add_action('wp_footer','output'); 】output()函数。。。

这样就输出了"<div id='my_test'>这是我的第一个插件!</div>"了

最后贴一下do_action的源码,大家体会一下吧

复制PHP内容到剪贴板

PHP代码:

/**

* do_action() - Execute functions hooked on a specific action hook.

*

* This function invokes all functions attached to action hook <tt>$tag</tt>.

* It is possible to create new action hooks by simply calling this function,

* specifying the name of the new hook using the <tt>$tag</tt> parameter.

*

* You can pass extra arguments to the hooks, much like you can with apply_filters().

*

* @see apply_filters() This function works similar with the exception that nothing is

* returned and only the functions or methods are called.

*

* @package WordPress

* @subpackage Plugin

* @since 1.2

* @global array $wp_filter Stores all of the filters

* @global array $wp_actions Increments the amount of times action was triggered.

*

* @param string $tag The name of the action to be executed.

* @param mixed $arg,... Optional additional arguments which are passed on to the functions hooked to the action.

* @return null Will return null if $tag does not exist in $wp_filter array

*/

function do_action($tag, $arg = '') {

global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;

if ( is_array($wp_actions) )

$wp_actions[] = $tag;

else

$wp_actions = array($tag);

$wp_current_filter[] = $tag;

// Do 'all' actions first

if ( isset($wp_filter['all']) ) {

$all_args = func_get_args();

_wp_call_all_hook($all_args);

}

if ( !isset($wp_filter[$tag]) ) {

array_pop($wp_current_filter);

return;

}

$args = array();

if ( is_array($arg) && 1 == count($arg) && is_object($arg[0]) ) // array(&$this)

$args[] =& $arg[0];

else

$args[] = $arg;

for ( $a = 2; $a < func_num_args(); $a++ )

$args[] = func_get_arg($a);

// Sort

if ( !isset( $merged_filters[ $tag ] ) ) {

ksort($wp_filter[$tag]);

$merged_filters[ $tag ] = true;

}

reset( $wp_filter[ $tag ] );

do {

foreach ( (array) current($wp_filter[$tag]) as $the_ )

if ( !is_null($the_['function']) )

call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));

} while ( next($wp_filter[$tag]) !== false );

array_pop($wp_current_filter);

}

其中比较关键的就是call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));这句了

 
 
 
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