pluging dev

8/11/2019 Pluging Dev

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Pluging Dev

Plugin activation/deactivation

register_activation_hook( __FILE__,

'function_to_execute_after_registration' );

function_to_execute_after_registration(){

}

Called when a plugin is going to be registered or activated

Register_deactivation_hook(__FILE__, function_to_execute)

Local Paths

To determine the local server path to your plugin, youll use the

plugin_dir_path() function. This function extracts the physical

location relative to the plugins directory from its file name.

plugins_url( 'images/icon.png', __FILE__ )

Usefull Urls

WordPress also features various functions to determine URLs in

WordPress. The following is a list of the functions available:

admin_url()Admin URL (http://example.com/wp-admin/)

site_url()Site URL for the current site (http://example.com)

home_url()Home URL for the current site (http://example.com)

includes_url()Includes directory URL (http://example.com/wp-

includes/)


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content_url()Content directory URL (http://example.com/wp-

content/)

wp_upload_dir()Returns an array with location information on the

configured uploads Directory

Hook

A hook is simply a PHP function call with various parameters that can

be sent. Following is an

example showing a properly formatted Action hook call:

The add_filter() function is used to execute a Filter action. You are

using the fi lter called the_content, which is the filter for your

post content. This tells WordPress that every time the content is

displayed, it needs to pass through your custom function called

prowp_function().

The add_filter() function can accept four parameters:

1. filter_action (string): The fi lter to use

2. custom_filter_function (string): The custom function to pass the fi

lter through

3. priority (integer): The priority in which this fi lter should run.

When multiple callback

functions are attached to the same hook, the priority parameter

determines the execution

order

4. accepted args (integer): The number of arguments the function

accepts


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Popular Filter Hooks

More than 1,500 different hooks are available in WordPress, which is a

bit overwhelming at fi rst.

Fortunately, a handful of them are used much more often than the rest.

This section explores some

of the more commonly used hooks in WordPress.

Some of the more common Filter hooks are:

the_contentApplied to the content of the post or page before

displaying


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the_content_rssApplied to the content of the post or page for RSS

inclusion

the_titleApplied to the post or page title before displaying

comment_textApplied to the comment text before displaying

wp_titleApplied to the page before displaying

the_permalinkApplied to the permalink URL


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The default_contentFilter hook is useful for setting the default

content when creating a new post

or page. This is helpful if you have a set format for all of your

posts as it can save you valuable

writing time:

Filter hooks are exceptionally powerful for inserting your own

processing into a variety of points in

the Loop processing of each post. Realizing the full power of the

WordPress plugin system means

also using action hooks to fi re your own code in response to eventswithin the WordPress core.

Popular Action Hooks

Some of the more common Action hooks are:

publish_postTriggered when a new post is published.

create_categoryTriggered when a new category is created.

switch_themeTriggered when you switch themes.

admin_headTriggered in the section of the admin dashboard.

wp_headTriggered in the section of your theme.


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wp_footerTriggered in the footer section of your theme usually

directly before the tag.

initTriggered after WordPress has finished loading, but before

any headers are sent.

Good place to intercept $_GET and $_POST HTML requests.

admin_init: Same as init but only runs on admin dashboard pages.

user_register: Triggered when a new user is created.

comment_post: Triggered when a new comment is created.

a {

font-size: 14px; color: #000000; text-decoration: none;

}

a:hover { font-size: 14px; color: #FF0000; text-decoration:

underline;}

The wp_footer hook is also a very commonly used Action hook. Using

this hook you can insert any custom code in the footer of the


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WordPress theme. This is a great method for adding analytic tracking

code to your website:

var gaJsHost = (("https:" == document.location.protocol) ?

"https://ssl." : "http://www.");

document.write(unescape("%3Cscript src='" + gaJsHost +

'google-analytics.com/ga.js'

type='text/javascript'%3E%3C/script%3E"));

var pageTracker = _gat._getTracker("UA-XXXXXX-XX");

pageTracker._trackPageview();

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