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WordPress: Creating Custom Widgets and Plugins with PHP
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Introduction to hooks


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WordPress: Creating Custom Widgets and Plugins with PHP

with Drew Falkman

Video: Introduction to hooks

When you get down to it, there's one key element that allows for WordPress plugins, and that's the hook. Hooks are also known as actions and filters. They're basically points in the WordPress life cycle that go out and look for registered programming pieces to execute. This can occur when a user requests a page, when an admin page is created, when an admin menu is created, when the author submits a post, or at myriad of other places throughout WordPress. All of these pieces have hooks related to them. All we need to do to make a plugin work then is register a function to a specific hook, and bam: that's really all there is to it.
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  1. 1m 49s
    1. Welcome
      1m 16s
    2. Using the exercise files
      33s
  2. 23m 29s
    1. WordPress overview
      2m 32s
    2. Installing WPI for Windows
      3m 42s
    3. Installing MAMP for the Mac
      3m 25s
    4. Installing and configuring WordPress
      5m 51s
    5. Comparing WordPress 3.0 with previous versions
      2m 57s
    6. Setting up a PHP/WordPress development environment
      5m 2s
  3. 14m 47s
    1. Exploring WordPress plugins
      3m 42s
    2. Administering plugins from the WordPress admin
      5m 23s
    3. Exploring where plugins reside
      2m 51s
    4. Introduction to hooks
      2m 51s
  4. 39m 28s
    1. Creating the plugin PHP file(s)
      3m 12s
    2. More on hooks: Actions and filters
      3m 15s
    3. Installation and activation
      4m 6s
    4. Writing activation code
      3m 45s
    5. Writing an action
      5m 12s
    6. Writing a filter
      4m 15s
    7. About pluggable functions
      2m 1s
    8. Writing a pluggable function
      5m 30s
    9. Using template tags
      2m 46s
    10. Introducing shortcode
      5m 26s
  5. 26m 2s
    1. Widgets and the WordPress Widgets SubPanel
      2m 54s
    2. Comparing widgets and plugins
      1m 8s
    3. Using and customizing built-in widgets
      3m 18s
    4. Creating a new widget
      7m 21s
    5. Writing the constructor and registering widgets
      5m 20s
    6. Enabling configuration of widgets
      6m 1s
  6. 44m 59s
    1. Creating an admin interface
      5m 25s
    2. Saving data to the database
      5m 39s
    3. Securing form submission with nonces
      2m 25s
    4. Options editing post-WordPress 2.7
      4m 8s
    5. Integrating with the WordPress admin menus
      3m 34s
    6. WordPress admin dashboard API
      4m 5s
    7. Using existing options and option editing pages in WordPress
      5m 19s
    8. Using jQuery and AJAX for administration
      14m 24s
  7. 27m 13s
    1. Accessing the WordPress database
      5m 45s
    2. Using the built-in schema
      2m 21s
    3. Accessing data using $wpdb
      5m 15s
    4. Creating new tables
      7m 18s
    5. Inserting data
      6m 34s
  8. 26m 27s
    1. Introducing the Loop
      6m 22s
    2. Using WP_Query()
      3m 11s
    3. Custom filtering and sticky posts
      4m 58s
    4. Using jQuery and AJAX for posts and pages
      11m 56s
  9. 12m 9s
    1. Registering and promoting plugins
      2m 28s
    2. Creating an uninstall function
      5m 53s
    3. Backward compatibility issues
      3m 48s
  10. 15m 3s
    1. Understanding security issues
      11m 20s
    2. Internationalizing your plugin
      3m 43s
  11. 18s
    1. Goodbye
      18s

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WordPress: Creating Custom Widgets and Plugins with PHP
3h 51m Intermediate Nov 04, 2010

Viewers: in countries Watching now:

In WordPress: Creating Custom Widgets and Plugins with PHP, Drew Falkman teaches PHP developers how to create custom functionality for WordPress 2.0 through 3.0 using widgets and plugins. This course starts by installing and setting up WordPress 3.0 on both Mac and Windows, then provides an in-depth look at tasks related to these WordPress add-ons: installing and administering, building and customizing, creating editable options and database tables, working with posts and pages, and utilizing jQuery and AJAX. There are also tutorials dedicated to promoting a widget or plugin, adding security, and localizing the interface. Exercise files are included with the course.

Topics include:
  • Installing WPI and MAMP server solutions
  • Administering WordPress plugins
  • Introducing hooks
  • Writing the PHP for a plugin
  • Using template tags and shortcode
  • Building a new widget
  • Creating an admin interface
  • Accessing the WordPress database
  • Using jQuery and AJAX for posts and pages
  • Registering and promoting plugins
Subjects:
Developer Web CMS
Software:
WordPress
Author:
Drew Falkman

Introduction to hooks

When you get down to it, there's one key element that allows for WordPress plugins, and that's the hook. Hooks are also known as actions and filters. They're basically points in the WordPress life cycle that go out and look for registered programming pieces to execute. This can occur when a user requests a page, when an admin page is created, when an admin menu is created, when the author submits a post, or at myriad of other places throughout WordPress. All of these pieces have hooks related to them. All we need to do to make a plugin work then is register a function to a specific hook, and bam: that's really all there is to it.

That piece of code will execute when that hook occurs. WordPress hook started back in version 1.2. Before that, WordPress hacking was literally that. It was taking the original code and hacking away at it. When they added hooks, essentially what they did is they added points in the code that would look to see if anything was registered to execute at that particular point. So, for example, when the user submits a comment, there is a hook there. If you want something to happen, then you can write a function that will send out an e-mail, and then you add it into that hook.

Or let's say you want to add something to a menu in admin. You can write a function that generates some user interface, some display, and then simply add a hook. That hook will then add your piece of user interface into the display of the Admin menu. So the process of plugin development is really writing a function that does something, then finding the correct hook when you want that thing to occur, and simply registering your function with that hook. As a WordPress developer, a key part of getting started is using the WordPress Codex.

The Codex is really the user manual for WordPress, for everyone, whether they're an administrator or developer. But from a developer standpoint, we have a list of all kinds of stuff: specifically here at codex.WordPress.org/plugin_API. It's a great jumping point to get started. It will explain hooks, actions and filters, what they are, and it will also tell you some examples of actions and also of filters, and we'll talk about the distinctions in these later when we get into development.

In addition, Adam Brown at Brigham Young also has a database of all the WordPress hooks, called the WordPress Hooks Database at adambrown.info. So the key to plugins is the hook. The process of developing a plugin is really the process of writing a function, registering it with a hook, and then whenever that occurs in that process when the user uses your plugin, your functionality will occur.

Find answers to the most frequently asked questions about WordPress: Creating Custom Widgets and Plugins with PHP.


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Q: Do I need a web hosting service for this course?
A: You don't need a hosting site to do any testing or development work that’s covered in this course. However, if you want to have your WordPress site available to the public, you will most definitely need a WordPress site. If you are hosting with an independent company, they will need to have PHP and MySQL installed, and there will be some configuration differences, but basically, you can upload anything on your local version to the web site. If you are hosting with Wordpress.com, you will need to add your plugins by uploading them manually through the WP Admin Plugin screen.
 
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