Codex tools: Log in
L'objectif principal de l'utilisation des plugins est de maintenir le noyau de Wordpress intact, dans un soucis de stabilité et de mise à jour des futures versions.
Un plugin WordPress est un programme, écrit en langage PHP, permettant d'ajouter des fonctionnalités personnalisés à Wordpress.
Veillez à ce que le nom de votre plugin soit unique (voir la liste des plugins déposés Plugins ) La plupart des développeurs choisissent un nom en rapport avec la description du plugin, ce nom peut avoir plusieurs mots.
Encore une fois, choisissez un nom unique (pour éviter les conflits de doublons) en utilisant la convention de nommage des variables: - 1ère lettre en minuscule. - Majuscule avec la première lettre de chaque mot. - ex: superPlugin.php
Votre plugin peut contenir plusieurs fichiers, dans ce cas il faut mettre ces fichiers dans un répertoire du même nom que votre fichier principal. ex: wp-content/plugins/superPlugin/superPlugin.php...
If you want to host your plugin on http://wordpress.org/extend/plugins/, you also need to create a readme.txt file in a standard format, and include it with your plugin. See http://wordpress.org/extend/plugins/about/readme.txt for a description of the format.
It is also very useful to create a web page to act as the home page for your plugin. This page should describe how to install the plugin, what it does, what versions of WordPress it is compatible with, what has changed from version to version of your plugin, and how to use the plugin.
The top of your plugin's main PHP file must contain a standard plugin information header. This header lets WordPress recognize that your plugin exists, add it to the plugin management screen so it can be activated, load it, and run its functions; without the header, your plugin will never be activated and will never run. Here is the header format:
<?php /* Plugin Name: Name Of The Plugin Plugin URI: http://URI_Of_Page_Describing_Plugin_and_Updates Description: A brief description of the plugin. Version: The plugin's Version Number, e.g.: 1.0 Author: Name Of The Plugin Author Author URI: http://URI_Of_The_Plugin_Author */ ?>
The minimum information WordPress needs to recognize your plugin is the Plugin Name line. The rest of the information (if present) will be used to create the table of plugins on the plugin management screen. The order of the lines is not important.
It is customary to follow the standard header with information about licensing for the plugin. Most plugins use the GPL license used by WordPress or a license compatible with the GPL. To indicate a GPL license, include the following lines in your plugin:
<?php
/* Copyright YEAR PLUGIN_AUTHOR_NAME (email : PLUGIN AUTHOR EMAIL)
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
?>
Many plugins accomplish their goals by connecting to one or more WordPress plugin "hooks". The way plugin hooks work is that at various times while WordPress is running, WordPress checks to see if any plugins have registered functions to run at that time, and if so, the functions are run. These functions modify the default behavior of WordPress.
For instance, before WordPress adds the title of a post to browser output, it first checks to see if any plugin has registered a function for the "filter" hook called "the_title". If so, the title text is passed in turn through each registered function, and the final result is what is printed. So, if your plugin needs to add some information to the printed title, it can register a "the_title" filter function.
Another example is the "action" hook called "wp_footer". Just before the end of the HTML page WordPress is generating, it checks to see whether any plugins have registered functions for the "wp_footer" action hook, and runs them in turn.
You can learn more about how to register functions for both filter and action hooks, and what plugin hooks are available in WordPress, in Plugin API. If you find a spot in the WordPress code where you'd like to have an action or filter, but WordPress doesn't have one, you can also suggest new hooks (suggestions will generally be taken); see Reporting Bugs to find out how.
Another way for a plugin to add functionality to WordPress is by creating custom Template Tags. Someone who wants to use your plugin can add these "tags" to their theme, in the sidebar, post content section, or wherever it is appropriate. For instance, a plugin that adds geographical tags to posts might define a template tag function called geotag_list_states() for the sidebar, which lists all the states posts are tagged with, with links to the state-based archive pages the plugin enables.
To define a custom template tag, simply write a PHP function and document it for plugin users on your plugin's home page and/or in the plugin's main PHP file. It's a good idea when documenting the function to give an example of exactly what needs to be added to the theme file to use the function, including the <?php and ?>.
Most plugins will need to get some input from the site owner or blog users and save it between sessions, for use in its filter functions, action functions, and template functions. This information has to be saved in the WordPress database, in order to be persistent between sessions. There are two basic methods for saving plugin data in the database:
See Creating Options Pages for info on how to create a page that will automatically save your options for you.
WordPress has a mechanism for saving, updating, and retrieving individual, named pieces of data ("options") in the WordPress database. Option values can be strings, arrays, or PHP objects (they will be "serialized", or converted to a string, before storage, and unserialized when retrieved). Option names are strings, and they must be unique, so that they do not conflict with either WordPress or other plugins.
Here are the main functions your plugin can use to access WordPress options.
add_option($name, $value, $description, $autoload);
get_option($option);
update_option($option_name, $newvalue);
Assuming that your plugin has some options stored in the WordPress database (see section above), you will probably want it to have an administration panel that will enable your plugin users to view and edit option values. The methods for doing this are described in Adding Administration Menus.
Once you have the programming for your plugin done, another consideration (assuming you are planning on distributing your plugin) is internationalization. Internationalization is the process of setting up software so that it can be localized; localization is the process of translating text displayed by the software into different languages. WordPress is used all around the world, so it has internationalization and localization built into its structure, including localization of plugins. For background on WordPress's use of GNU gettext for localization, see Translating WordPress.
It is highly recommended that you internationalize your plugin, so that users from different countries can localize it. The process is fairly straightforward:
$fabfunc_domain = 'fabfunc';
$fabfunc_is_setup = 0;
function fabfunc_setup()
{
global $fabfunc_domain, $fabfunc_is_setup;
if($fabfunc_is_setup) {
return;
}
load_plugin_textdomain($fabfunc_domain, 'wp-content/plugins');
}
If your plugin is in its own subdirectory, append that to the second argument of load_plugin_textdomain.
If you are reading this section because you want to internationalize a Theme, you can basically follow the steps above, except:
load_theme_textdomain('your_domain');
This last section contains some random suggestions regarding plugin development.
