A brief analysis of WordPress plug-in execution flow _php tutorial

1, first, I now Pugins folder to write a plugin of their own
Copy PHP content to clipboard
PHP Code:

/*
Plugin Name:test
Plugin URI: [url=http://wordpress.org/]http://wordpress.org/[/url]#
Description: I used the test.
AUTHOR:LW (Fantasy)
version:0.1
Author URI: [Url=http://www.xxx.com/]http://www.xxx.com/[/url]
*/

$test = "This is my first plugin!";

function output () {
Global $test;
Echo $test;
}

Add_action (Wp_footer,output);
?>

Then enable in the background:

2, WP execution is loaded in "wp-settings.php", and in this file, you can find the following plug-in-related code snippets:
Copy PHP content to clipboard
PHP Code:
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);
}
}
}

I dump the $current_plugins and get

Array
(
[0] = fanfou-daily/fanfou-daily.php
[1] = mulberrykit.php
[2] = test.php
)

You can see that the test.php plugin I wrote has been included in the include.

3, in the theme template footer.php inside will execute a function

And this wp_footer is executed inside.

Do_action (Wp_footer);

And this do_action is the implementation of the previous we have registered "add_action (wp_footer,output); The output () function ...

This will output "This is my first plugin!" The

Finally paste the Do_action source code, we appreciate it
Copy PHP content to clipboard
PHP Code:
/**
* Do_action ()-Execute functions hooked on a specific action hook.
*
* This function invokes all functions attached to action hook$tag.
* It is possible to the create new action hooks by simply calling the This function,
* Specifying the name of the new hook using the$tagParameter.
*
* Can pass extra arguments to the hooks and much like you can with Apply_filters ().
*
* @see apply_filters () This function works similar with the exception it is
* Returned and only the functions or methods is 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 is passed on to the functions hooked to the action.
* @return NULL would 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);
}

The key is Call_user_func_array ($the _[function], array_slice ($args, 0, (int) $the _[accepted_args]).

http://www.bkjia.com/PHPjc/508294.html www.bkjia.com true http://www.bkjia.com/PHPjc/508294.html techarticle 1, first, I now Pugins folder to write a copy of their own plug-in PHP content to the Clipboard PHP code:? PHP/* Plugin name:test Plugin URI: [url=http://wordpress.org/]http ://word ...

