Creating Wordpress Plugins

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Creating Wordpress Plugins
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Who is Here?

• PHP GTA Meetup
• Wordpress Toronto Meetup
• East Toronto Web Design Meetup

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About Me Peter Meth

• Degree in Computer Science
• Full time web application developer
• Also do websites, hosting, consulting
• PHP, MySQL, HTML, CSS, Javascript
• Wordpress, Joomla

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What is Wordpress?

• Most popular Blogging System in the World
• Most popular Content Management System in the
  World
• Used by 13 of the world's top million websites
• Its free and Open Source

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What is a Plugin?

• Add functionality without changing core files
• Use Wordpress API to interact with Wordpress
• Not overwritten when Wordpress gets updated
• 13,000 Free Plugins on Wordpress.org
• Commercial Plugins also available

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Why Create Plugins for Wordpress?

• Add functionality for existing Wordpress users
• Take advantage of Wordpress security, stability,
  infrastructure, templates
• Exposure to a huge userbase
• You may have your own reasons

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Naming File Structure

• Give your plugin a unique name
• Create a main php file
• You can create your own directory structure
• gets installed in plugins directory
• pathtowordpress/wp-content/plugins/

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Standard Header

• lt?php
• /
• Plugin Name Name Of The Plugin
• Description A brief description of the Plugin.
• ..
• ..
• /
• ?gt

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Activating Your Plugin

• Copy all files to
• pathtowordpress/wp-content/plugins/
• Load the wordpress admin
• http//www.yoursite.com/wordpress/wp-admin
• go to the Plugins menu, click Activate
• Lets have a look...

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Filters

• Filters change text as it gets written or
  processed
• add_filter('hook_name','myfilter')
• function myfilter(content)
• ...
• return content
• http//codex.wordpress.org/Plugin_APIFilters
• Lets have a look...

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Actions

• Actions are the steps that Wordpress takes to
  create a page
• add_action('hook_name','myaction')
• function myaction()
• ...
• http//codex.wordpress.org/Plugin_APIActions

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Creating a Menu

• Create a new function
• call add_menu_page(..) within it
• add your function to the admin_menu action
• add_action('admin_menu','mymenu')
• use if(is_admin()) for safety
• Lets have a look...

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Creating a Settings Page

• Create a function that outputs a form
• In the form set actionoptions.php
• call settings_fields(..) inside your form
• register your fields register_setting(..)
• use get_option(..) to retrieve values
• Lets have a look...

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Other Ways to Manage Data

• Create your own tables and forms
• Use Wordpress built in Options mechanism
• Use Custom Fields mechanism to add fields to
  Posts
• Beyond Scope of this presentation

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Want More Information?

• http//wordpress.org/extend/plugins
• http//codex.wordpress.org
• http//www.lynda.com
• (paid videos)
• http//www.wpplugins.com
• (commercial plugins)
• B2Template plugin by Dan Imbrogno

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Questions Answers