32,99 €
Mehr erfahren.
- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
- Veröffentlichungsjahr: 2020
Extend WordPress with plugins using this advanced WordPress development book, updated for the current version This significantly updated edition of Professional WordPress Plugin Development addresses modern plugin development for WordPress, the highly popular content management system (CMS). If you're using WordPress to create and manage websites, WordPress plugins are the software that can extend or enhance CMS functionality. This book offers guidance on writing plugins for WordPress sites to share or sell to other users. The second edition of Professional WordPress Plugin Development covers the building of advanced plugin development scenarios. It discusses the plugin framework and coding standards as well as dashboards, settings, menus, and related application programming interfaces (APIs). Additional topics include security, performance, data validation, and SQL statements. * Learn about the power of hooks in WordPress * Discover how JavaScript and Ajax will work in your site * Understand key technologies: Block Editor/Gutenberg, JS/React, PHP, and the REST API * Create and use custom post types and taxonomies. * Creating custom dashboard menus and plugin settings * Work with users and user data * Schedule tasks and utilizing Cron * Performance and security considerations Written by experienced plugin developers, Professional WordPress Plugin Development also helps you internationalize and localize your WordPress website. Find out about debugging systems and optimizing your site for speed. As WordPress use continues to increase, you can elevate your professional knowledge of how to extend WordPress through plugins.
Sie lesen das E-Book in den Legimi-Apps auf:
Seitenzahl: 660
Ähnliche
Table of Contents
COVER
FOREWORD
INTRODUCTION
WHO THIS BOOK IS FOR
WHAT YOU NEED TO USE THIS BOOK
WHAT THIS BOOK COVERS
HOW THIS BOOK IS STRUCTURED
CONVENTIONS
SOURCE CODE
ERRATA
1 An Introduction to Plugins
WHAT IS A PLUGIN?
AVAILABLE PLUGINS
ADVANTAGES OF PLUGINS
INSTALLING AND MANAGING PLUGINS
SUMMARY
2 Plugin Framework
REQUIREMENTS FOR PLUGINS
BEST PRACTICES
PLUGIN HEADER
DETERMINING PATHS
ACTIVATE/DEACTIVATE FUNCTIONS
UNINSTALL METHODS
CODING STANDARDS
SUMMARY
3 Dashboard and Settings
ADDING MENUS AND SUBMENUS
PLUGIN SETTINGS
THE OPTIONS API
THE SETTINGS API
KEEPING IT CONSISTENT
SUMMARY
4 Security and Performance
SECURITY OVERVIEW
USER PERMISSIONS
NONCES
DATA VALIDATION AND SANITIZATION
FORMATTING SQL STATEMENTS
SECURITY GOOD HABITS
PERFORMANCE OVERVIEW
CACHING
TRANSIENTS
SUMMARY
5 Hooks
UNDERSTANDING HOOKS
ACTIONS
FILTERS
USING HOOKS FROM WITHIN A CLASS
USING HOOKS WITH ANONYMOUS FUNCTIONS
CREATING CUSTOM HOOKS
FINDING HOOKS
SUMMARY
6 JavaScript
REGISTERING SCRIPTS
ENQUEUEING SCRIPTS
LIMITING SCOPE
LOCALIZING SCRIPTS
INLINE SCRIPTS
OVERVIEW OF BUNDLED SCRIPTS
POLYFILLS
YOUR CUSTOM SCRIPTS
jQuery
BACKBONE/UNDERSCORE
REACT
SUMMARY
7 Blocks and Gutenberg
WHAT IS GUTENBERG?
TOURING GUTENBERG
PRACTICAL EXAMPLES
TECHNOLOGY STACK OF GUTENBERG
“HELLO WORLD!” BLOCK
WP‐CLI SCAFFOLDING
CREATE‐GUTEN‐BLOCK TOOLKIT
BLOCK DIRECTORY
SUMMARY
8 Content
CREATING CUSTOM POST TYPES
POST METADATA
META BOXES
CREATING CUSTOM TAXONOMIES
USING CUSTOM TAXONOMIES
A POST TYPE, POST METADATA, AND TAXONOMY PLUGIN
SUMMARY
9 Users and User Data
WORKING WITH USERS
ROLES AND CAPABILITIES
LIMITING ACCESS
CUSTOMIZING ROLES
SUMMARY
10 Scheduled Tasks
WHAT IS CRON?
SCHEDULING CRON EVENTS
TRUE CRON
PRACTICAL USE
SUMMARY
11 Internationalization
INTERNATIONALIZATION AND LOCALIZATION
CREATING TRANSLATION FILES
SUMMARY
12 REST API
WHAT THE REST API IS
WHAT YOU CAN DO WITH THE REST API
ACCESSING THE WORDPRESS REST API
THE HTTP API
WORDPRESS’ HTTP FUNCTIONS
BRINGING IT ALL TOGETHER
SUMMARY
13 Multisite
TERMINOLOGY
ADVANTAGES OF MULTISITE
ENABLING MULTISITE IN WORDPRESS
MULTISITE FUNCTIONS
DATABASE SCHEMA
QUERY CLASSES
OBJECT CLASSES
SUMMARY
14 The Kitchen Sink
QUERYING AND DISPLAYING POSTS
SHORTCODES
WIDGETS
DASHBOARD WIDGETS
REWRITE RULES
THE HEARTBEAT API
SUMMARY
15 Debugging
COMPATIBILITY
DEBUGGING
ERROR LOGGING
QUERY MONITOR
SUMMARY
16 The Developer Toolbox
CORE AS REFERENCE
PLUGIN DEVELOPER HANDBOOK
CODEX
TOOL WEBSITES
COMMUNITY RESOURCES
TOOLS
SUMMARY
INDEX
END USER LICENSE AGREEMENT
List of Tables
Chapter 3
TABLE 3-1: List of Core Sections and Fields
Chapter 12
TABLE 12-1: Main HTTP Status Codes
TABLE 12-2: HTTP Status Code Classes
TABLE 12-3: Default Settings of wp_remote_ Functions Optional Parameters
List of Illustrations
Chapter 1
FIGURE 1-1: Loading a page in WordPress
FIGURE 1-2: Plugins menu
FIGURE 1-3: Install Now button
FIGURE 1-4: Types and statuses for plugins
Chapter 3
FIGURE 3-1: Custom registered menu
FIGURE 3-2: Submenus
FIGURE 3-3: Submenu labeled PDEV Settings
FIGURE 3-4: Plugin management page
FIGURE 3-5: Error message
FIGURE 3-6: Section appended
FIGURE 3-7: Singular field
FIGURE 3-8: Heading levels
FIGURE 3-9: Dashicons
FIGURE 3-10: Dismissable notices
FIGURE 3-11: WordPress-styled button
FIGURE 3-12: Link styled to look like a button
FIGURE 3-13: WordPress-like options
FIGURE 3-14: Table style
FIGURE 3-15: Pagination style
Chapter 4
FIGURE 4-1: Insufficient privileges
FIGURE 4-2: Expired link message
FIGURE 4-3: Rogue JavaScript running
FIGURE 4-4: Related Posts list
Chapter 7
FIGURE 7-1: Classic Editor, not covered in this chapter
FIGURE 7-2: Gutenberg
FIGURE 7-3: Block Library menu
FIGURE 7-4: Categories of blocks
FIGURE 7-5: View options
FIGURE 7-6: Sidebar's Document menu
FIGURE 7-7: Sidebar's Block menu and formatting toolbar
FIGURE 7-8: WooCommerce blocks
FIGURE 7-9: Newest Products block
FIGURE 7-10: Event Calendar blocks
FIGURE 7-11: Post Type Switcher plugin
FIGURE 7-12: webpack finishing successfully
FIGURE 7-13: Our “Hello world!” block in the Block Library
FIGURE 7-14: Selecting our new block
FIGURE 7-15: Editing a post
FIGURE 7-16: WP-CLI scaffold generated
FIGURE 7-17: Build Step 1
FIGURE 7-18: Build Step 2
FIGURE 7-19: Build Step 3
FIGURE 7-20: My Block in Block Library
FIGURE 7-21: My Block in Content Area
Chapter 8
FIGURE 8-1: Books admin menu and screen
FIGURE 8-2: Tags submenu item
FIGURE 8-3: Genres submenu
Chapter 9
FIGURE 9-1: New form on the user edit page
FIGURE 9-2: New roles
Chapter 10
FIGURE 10-1: Scheduled Events page
FIGURE 10-2: Number output
Chapter 11
FIGURE 11-1: Settings box
Chapter 12
FIGURE 12-1: Unformatted JSON
FIGURE 12-2: Formatted JSON
FIGURE 12-3: Post results
FIGURE 12-4: Error message
FIGURE 12-5: Authentication worked
FIGURE 12-6: “My Time at Crystal Lake” post
Chapter 13
FIGURE 13-1: Tools ➪ Network menu options
Chapter 14
FIGURE 14-1: Simple post list
FIGURE 14-2: Widgets admin screen
FIGURE 14-3: Favorites list
FIGURE 14-4: Custom dashboard widget
FIGURE 14-5: Custom dashboard widget
Chapter 15
FIGURE 15-1: Admin Toolbar menu item
FIGURE 15-2: Query Monitor interface
FIGURE 15-3: Database queries
Chapter 16
FIGURE 16-1: Function with parameters
FIGURE 16-2: Codex search options
FIGURE 16-3: WordPress PHPXref
FIGURE 16-4: Function list
Guide
Cover
Table of Contents
Begin Reading
Pages
v
xxix
xxxi
xxxii
xxxiii
xxxiv
1
2
3
4
5
6
7
8
9
10
11
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
vi
vii
ix
xi
447
PROFESSIONAL WORDPRESS® PLUGIN DEVELOPMENT
Second Edition
Brad Williams
Justin Tadlock
John James Jacoby
FOREWORD
This book will teach you how to develop for WordPress. WordPress has, over the past two decades, grown into the CMS that powers more than one‐third of all websites. If you're proficient at WordPress development, you'll never be out of a job again.
Starting out as a simple blogging system, over the last few years WordPress has morphed into a fully featured and widely used content management system. It offers individuals and companies worldwide a free and open source alternative to closed source and often very expensive systems.
When I say fully featured, that's really only true because of the ability to add any functionality needed in the form of a plugin. The core of WordPress is simple: you add in functionality with plugins as you need it. Developing plugins allows you to stand on the shoulders of a giant: you can showcase your specific area of expertise and help users benefit while not having to deal with parts of WordPress you don't care or know about.
When I wrote the foreword of this book's first edition, nine years ago, I'd just started my own company. That company has since grown to consist of 100+ people, and our plugins are used on more than 10 million sites—all through the power of open source and plugins.
I wished that when I started developing plugins for WordPress as a hobby, almost 15 years back, this book had been around. I used it as a reference countless times since, and I still regularly hand this book to new colleagues.
The authors of this book have always been a source of good information and wonderful forces in the WordPress community. Each of them is an expert in his own right; together they are one of the best teams that could have been gathered to write this book, and I'm glad they're here for a second edition.
WordPress makes it easy for people to have their say through words, sound, and visuals. For those who write code, WordPress allows you to express yourself in code. And it's simple. Anyone can write a WordPress plugin. With this guide in hand, you can write a plugin that is true to WordPress’ original vision: code is poetry.
Happy coding!
Joost de Valk
Yoast.com
INTRODUCTION
Dear reader, thank you for picking up this book! You have probably heard about WordPress already, the most popular self‐hosted content management system (CMS) and blogging software in use today. WordPress powers literally millions of websites on the Internet, including high‐profile sites such as TechCrunch and multiple Microsoft websites. What makes WordPress so popular is that it's free, open source, and extendable beyond limits. Thanks to a powerful, architecturally sound, and easy‐to‐use plugin system, you can customize how WordPress works and extend its functionalities. There are already more than 55,000 plugins freely available in the official plugin repository, but they won't suit all your needs or client requests. That's where this book comes in handy!
As of this writing, we (Brad, Justin, and John) have publicly released more than 100 plugins, which have been downloaded millions of times, and that's not counting private client work. This is a precious combined experience that we are going to leverage to teach you how to code your own plugins for WordPress by taking a hands‐on approach with practical examples and real‐life situations you will encounter with your clients.
The primary reason we wanted to write this book is to create a preeminent resource for WordPress plugin developers. When creating plugins for WordPress, it can be a challenge to find the resources needed in a single place. Many of the online tutorials and guides are outdated and recommend incorrect methods for plugin development. This book is one of the most extensive collections of plugin development information to date and should be considered required reading for anyone wanting to explore WordPress plugin development from the ground up.
WHO THIS BOOK IS FOR
This book is for professional web developers who want to make WordPress work exactly how they and their clients want. WordPress has already proven an exceptional platform for building any type of site from simple static pages to networks of full‐featured communities. Learning how to code plugins will help you get the most out of WordPress and have a cost‐effective approach to developing per‐client features.
This book is also for the code freelancers who want to broaden their skill portfolio, understand the inner workings of WordPress functionality, and take on WordPress gigs. Since WordPress is the most popular software to code and power websites, it is crucial that you understand how things run under the hood and how you can make the engine work your way. Learning how to code plugins will be a priceless asset to add to your résumé and business card.
Finally, this book is for hobbyist PHP programmers who want to tinker with how their WordPress blog works, discover the infinite potential of lean and flexible source code, and learn how they can interact with the flow of events. The beauty of open source is that it's easy to learn from and easy to give back in turn. This book will help you take your first step into a community that will welcome your creativity and contribution.
Simply put, this book is for anyone who wants to extend the way WordPress works, whether it is for fun or profit.
WHAT YOU NEED TO USE THIS BOOK
This book assumes you already have a web server and WordPress running. For your convenience, it is preferred that your web server runs on your localhost, as it will be easier to modify plugin files as you read through the book, but an online server is also fine.
Code snippets written in PHP are the backbone of this book. You should be comfortable with reading and writing basic PHP code or referring to PHP's documentation to fill any gaps in knowledge about fundamental functions. Advanced PHP code tricks are explained, so you don't need to be a PHP expert.
You will need to have rudimentary HTML knowledge to fully understand all the code. A basic acquaintance with database and MySQL syntax will help with grasping advanced subjects. To make the most of the chapter dedicated to JavaScript and Ajax, comprehension of JavaScript code will be a plus.
WHAT THIS BOOK COVERS
As of this writing, WordPress 5.5 is around the corner, and this book has been developed alongside this version. Following the best coding practices outlined in this book and using built‐in APIs are keys to future‐proof code that will not be deprecated when a newer version of WordPress is released. We believe that every code snippet in this book will still be accurate and up‐to‐date for several years, just as several plugins we coded many years ago are still completely functional today.
HOW THIS BOOK IS STRUCTURED
This book is, to date, one of the most powerful and comprehensive resources you can find about WordPress plugins. Advanced areas of the many WordPress APIs are covered, such as the REST API, cron jobs, and custom post types. This book is divided into three major parts. Reading the first five chapters is required if you are taking your first steps in the wonders of WordPress plugins. Chapters 6 through 9 will cover most common topics in coding plugins, and understanding them will be useful when reading subsequent chapters. The remaining chapters cover advanced APIs and functions, can be read in any order, and will sometimes refer to other chapters for details on a particular function.
CONVENTIONS
To help you get the most from the text and keep track of what's happening, we've used a number of conventions throughout the book.
WARNING Boxes with a warning label like this one hold important, not‐to‐be‐forgotten information that is directly relevant to the surrounding text.
NOTE The note label indicates notes, tips, hints, tricks, and asides to the current discussion.
As for styles in the text:
We
italicize
new terms and important words when we introduce them.
We show keyboard strokes like this: Ctrl+A.
We show filenames, URLs, and code within the text like so: persistence.properties.
We present code in two different ways:
We use a monofont type with no highlighting for most code examples.
We use bold to emphasize code that is particularly important in the present context or to show changes from a previous code snippet.
SOURCE CODE
As you work through the examples in this book, you may choose either to type in all the code manually or to use the source code files that accompany the book. All the source code used in this book is available for download at www.wiley.com/go/prowordpressdev2e on the Downloads tab.
NOTE Because many books have similar titles, you may find it easiest to search by ISBN; this book's ISBN is 978‐1‐119‐66694‐3.
ERRATA
We make every effort to ensure that there are no errors in the text or in the code. However, no one is perfect, and mistakes do occur. If you find an error in one of our books, such as a spelling mistake or faulty piece of code, we would be grateful for your feedback. By sending in errata, you may save another reader hours of frustration, and at the same time, you will be helping us provide even higher‐quality information.
To find the errata page for this book, go to www.wiley.com and locate the title using the Search box. Then, on the book details page, click the Errata link. On this page, you can view all errata that have been submitted for this book and posted by editors. If you don't spot “your” error on the Errata page, go to support.wiley.com and follow the directions to contact technical support and open a ticket to submit the error. We'll check the information and, if appropriate, post a message to the book's errata page and fix the problem in subsequent printings of the book.
