wordpress plugin development short tutorial

The first steps…• Pre‐development issues

– Wordpress Plugin Directory– Plugin and File Names– File Headers

• Wordpress Plugin Hooks – Actions – Filters

• Adding data to wordpress database– Creating tables with plugins

• Adding Administration Menus– Creating options page

• “Hello Dolly” example11/10/2008 2

Wordpress Plugin Development ‐ A Short Tutorial

Pre‐development issues (1)Wordpress Plugin Directory

11/10/2008 3Wordpress Plugin Development ‐ A Short

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wp‐content plugins your plugin

code

javascript

css

imagesplace your plugin here

Pre‐development issues (2)

11/10/2008Wordpress Plugin Development ‐ A Short

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Plugin and File Names

Choose your plugin’s name carefully. Think about what the plugin will do, and make a, hopefully unique, name for it.

It is good for the names of your php files to be derived from your chosen plugin name.

Pre‐development issues (3)


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File Headers

Wordpress Plugin Hooks (1)


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Hooks are provided to allow your plugin to 'hook into' the restof WordPress; that is, to call functions in your plugin at specifictimes, and thereby set your plugin in motion.

Hooks



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Hooks = Actions + Filters

Actions are triggered by specific events (e.g. publishing a post ) that take place in WordPress. Your plugin can respondto the event by executing a PHP function

EventAction



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Hooks = Actions + Filters

DATA

Filters - Functions

Filters are functions that WordPress passes data throughat certain points in execution, just before taking someaction with the data such as adding it to the database orsending it to the browser screen.

Adding data to Wordpress database


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Create tables with pluginsThere are two types of information you could store

• Setup Information: user choices that are entered when the user first sets upyour plugin.

• Data: information that is added as the user continues to use your plugin

Steps…

1. Write a PHP function that creates the table.

2. Ensure that WordPress calls the function when the plugin is activated.

3. Create an upgrade function, if a new version of your plugin needs to have a different table structure.

http://codex.wordpress.org/Creating_Tables_with_Plugins#Create_Database_Tables

$table_name = $wpdb->prefix . "liveshoutbox";

// check if there is a table with the same nameif($wpdb->get_var("show tables like '$table_name'") != $table_name) {

// SQL Statement$sql = "CREATE TABLE " . $table_name . " (

id mediumint(9) NOT NULL AUTO_INCREMENT,

time bigint(11) DEFAULT '0' NOT NULL,

name tinytext NOT NULL,

text text NOT NULL,

url VARCHAR(55) NOT NULL,

UNIQUE KEY id (id)

);";

// Creating the tablerequire_once(ABSPATH . 'wp-admin/includes/upgrade.php');

dbDelta($sql);

A simple example

$welcome_name = "Mr. Wordpress"; $welcome_text = "Congratulations, you just completed the installation!";

// SQL Statememt$insert = "INSERT INTO " . $table_name . " (time, name, text) " . "VALUES ('" . time() . "','" . $wpdb->escape($welcome_name) . "','" . $wpdb->escape($welcome_text) .

"')";

// Adding Data into the table$results = $wpdb->query( $insert );

A simple example

Adding Administration Menus


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Create options pageTop-level menus: Settings, Manage, Plugins, Presentation, Write, Users

Admin Menu Functions

• add_menu_page: create a top-level menu

• add_submenu_page: define one or more sub-menu pages

In the above wordpress functions the developers defined the name of their phpfunctions which are responsible to build the options pages.

See an example here

http://codex.wordpress.org/Creating_Options_Pages

Hello Dolly example


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Hello Dolly Lyrics Chose randomly one lyric and place it the upper right of your Administationpanels

add_action('admin_footer', 'hello_dolly');

Wordpress Development Community


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Are you ready to enter into an evolving development community?

Matt Mullenweg


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Creator of Wordpress.org

14th place The 25 most influential people on the web

(2008)

More details on the internet…


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The truth is out there…

http://codex.wordpress.org/Writing_a_Plugin#WordPress_Plugin_Hooks

http://codex.wordpress.org/Plugin_API

http://codex.wordpress.org/Creating_Tables_with_Plugins

http://codex.wordpress.org/Adding_Administration_Menus


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THE END

Thank you!

wordpress plugin development short tutorial

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