Wordpress 3 Plugin Development Essentials电子书

WordPress 3 Plugin Development Essentials

Table of Contents

WordPress 3 Plugin Development Essentials

Credits

About the Authors

About the Reviewers

www.PacktPub.com

Support files, eBooks, discount offers and more

Why Subscribe?

Free Access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code for this book

Errata

Piracy

Questions

1. Preparing for WordPress Development

WordPress background

Extending WordPress

Understanding WordPress architecture

Templating

Introducing plugins

Summarizing architecture

Tools for web development

WordPress

Mac

Windows

Text editor

Using an IDE

FTP client

MySQL client

Coding best practices

Basic organization

Isolate tasks into functions

Use classes

Use descriptive variable names

Use descriptive function names

Separate logic and display layers

Go modular, to a point

Avoid short tags

Planning ahead / starting development

Interfaces

Localization

Documentation for the developer

Version control

Environment

Tests

Security

Printing user-supplied data to a page

Using user-supplied data to construct database queries

Debugging

Clearing your browser cache

Updating your php.ini file

Configuring your wp-config.php file

Checking your syntax

Checking values

Exercise

Summary

2. Anatomy of a Plugin

Deconstructing an existing plugin: "Hello Dolly"

Activating the plugin

Examining the hello.php file

Information header

Exercise—breaking the header

Location, name, and format

Understanding the Includes

Exercise – parse errors

Bonus for the curious

User-defined functions

Exercise—an evil functionless plugin

What just happened

Omitting the closing "?>" PHP tag

A better example: Adding functions

Referencing hooks via add_action() and add_filter()

Actions versus Filters

Exercise—actions and filters

Exercise—filters

Reading more

Summary

3. Social Bookmarking

The overall plan

Proof of concept

Avoiding conflicting function names

The master plugin outline

The plugin information header

In your browser—information header

Adding a link to the post content

Documenting our functions

In your browser—linking to the post content

Adding JavaScript to the head

Making our link dynamic

In your browser—dynamic links

Adding a button template

Getting the post URL

In your browser—getting the post URL

Getting the post title

Getting the description

Getting the media type

Getting the post topic

In your browser—title, description, and topic

Checking WordPress versions

Summary

4. Ajax Search

What is Ajax?

The overall plan

The proof of concept mock up

Hooking up jQuery

Test that jQuery has loaded

What happened?

Using the FireBug console directly

Writing HTML dynamically to a target div

Multi-line strings

Viewing the generated page

Anonymous functions

Adding a div on the fly

Create a listener

Fetching data from another page

Creating our plugin

Creating index.php and activating the plugin

Creating our first PHP class

Updating index.php

Testing your version of PHP

Testing for searchable pages

Adding your own CSS files

Adding your search handler

Adding your own JavaScript

Handling Ajax search requests

Formatting your search results

Summary

5. Content Rotator

The plan

Widget overview

Preparation

Activating your plugin

Activating the widget

Having problems?

Parents and children: extending classes

Objects vs. libraries: when to use static functions

Add custom text

Adding widget options

Generating random content

Expiration dates: adding options to our widget

Expiration dates: enforcing the shelf life

Explaining the $instance

Adding a custom manager page

Adding options to the custom manager page

Randomizing content from the database

Review of PHP functions used

Summary

6. Standardized Custom Content

What WordPress does for you: custom fields

What WordPress doesn't do for you

Standardizing a post's custom fields

Creating a new plugin

Removing the default WordPress form for custom fields

Creating our own custom meta box

Defining custom fields

Generating custom form elements

Saving custom content

Having trouble saving data?

Displaying custom data in your Templates

Copying a theme

Modifying the theme

Granular display of custom fields

Bonus for the MySQL curious

Known limitations

Summary

7. Custom Post Types

Background: What's in a name?

Understanding register_post_type()

Customizing our post type

Using shortcodes

Testing our shortcode

Customizing our plugin

Creating a settings shortcut link

Cleaning up when uninstalling

Summary

8. Versioning Your Code with Subversion (SVN)

Why Subversion?

Understanding the terminology and concepts

Checking out a local working copy

SVN folder structure

Checkout, revisited

Setting up an SVN repository

Checking out a local working copy of our repo

Adding files

Committing changes to the repository

Overcoming errors

Verifying the new state of your repository

Adding more files to your repository

Removing files from the repository

Updating your working copy

Tagging a version

Reverting an entire project

Reverting a single file

Moving files

Exporting your working copy

Quick reference

Summary

9. Preparing Your Plugin for Distribution

Public enemy number one: PHP notices

PHP short tags

Conflicting names

Modifying loader.php

Testing WordPress version

Testing PHP version

Testing MySQL version

Testing PHP modules

Testing WordPress installed plugins

Custom tests

Unit tests

WordPress limitations

Health check page

Storing test results in the database

Death to clippy: Use sensible configurations

Double check your interface

Documentation

Identify the purpose

Learning to drive: Keeping it relevant

Phrasebooks vs. dictionaries: Give examples

Analogy: The three bears

Analogy: PC load letter

The decalog of documentation

Summary

10. Publishing Your Plugin

Internationalization and localization

Processing each message

Choosing a textdomain

Best practices

Working with formatting

More advanced messages

Plural vs. singular

More complex messages

Notes to translators

Language files

Creating a POT file

Creating translations: .po files

Loading a textdomain

Updating a translation

Format for the readme.txt file

Section – installation

Section – Frequently Asked Questions

Section – screenshots

New addition – videos

Section – summary

Requesting and using SVN access

Publicity and promotion

Summary

A. Recommended Resources

PHP reference

Function reference

The WordPress forums

WebDev Studios

Viper007Bond

Kovshenin

SLTaylor

XPlus3

WP Engineer

Other plugins

B. WordPress API Reference

PHP functions

dirname

file_get_contents

preg_match

preg_replace

print_r

sprintf

strtolower

substr

WordPress Functions

__

_e

add_action

add_filter

add_meta_box

add_options_page

check_admin_referer

esc_html

get_option

get_post_meta

get_the_ID

register_post_type

remove_meta_box

screen_icon

the_content

the_meta

update_post_meta

wp_count_posts

wp_die

wp_nonce_field

Actions

admin_init

admin_menu

do_meta_boxes

init

save_post

widgets_init

wp_head

Filters

the_content

Index