Aaron Jorbin 8:22 pm on July 22, 2010
Tags: 3.org ( 9 ), handbooks ( 3 ), plugins ( 32 )

Plugin Developer Handbook Planning

I’ve started brainstorming ideas for the pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party developer handbook and have come up with a pretty long list of topics that I think should be covered. Some of these will be chapters on their own, some will be combined together and others still need to be thought of. For right now, the best feedback you could give me is to tell me what I missed and what you think might be out of scope.

A couple of notes:

I tried to include chapters so that both novice and experienced developers will be able use it. Hence ideas such as knowing the difference between the different languages used in WordPress.
Some things, while listed, I think will include warnings and language that discourages it. The two that stand out to me are: Custom database tables and Custom Option Pages.

Alright, now for the list:

Introduction
Languages of WP – Differences between PHPPHP The web scripting language in which WordPress is primarily architected. WordPress requires PHP 5.6.20 or higher, HTMLHTML HyperText Markup Language. The semantic scripting language primarily used for outputting content in web browsers., CSSCSS Cascading Style Sheets., JSJS JavaScript, a web scripting language typically executed in the browser. Often used for advanced user interfaces and behaviors.
WP Coding Standards
Organizing plugin files
Planning your plugin
Name Spacing
Adding Styles and Scripts
Actions / Filters
- How to use them
- How to add them to your theme so other plugins can use them
Shortcodes
Widgets
Front End Forms
Ajax
- Front end ajax
- Back End ajax
Roles and Capabilities and users
- Custom caps
- User MetaMeta Meta is a term that refers to the inside workings of a group. For us, this is the team that works on internal WordPress sites like WordCamp Central and Make WordPress.
Comments
- Comment Meta
- interacting with comment filters
Options
- Adding options to existing adminadmin (and super admin) pages
- Adding your own pages
transients
Translating / Internationalization
Custom Taxonomies
Custom Post Types
Scheduled events (pseudo-cron)
Activation / Removal hooksHooks In WordPress theme and development, hooks are functions that can be applied to an action or a Filter in WordPress. Actions are functions performed when a certain event occurs in WordPress. Filters allow you to modify certain functions. Arguments used to hook both filters and actions look the same.
Interacting with the database
- Adding Tables / interacting with them
Security
- Kses
- Escaping
- Capabilities check
- Nonces – Props Eric
Interacting with remote URLs
- atom / rss
Interacting with WP_Query
Media
- Media and Post relations (Send to editor)
Modifying / Creating URLs
MultiSitemultisite Used to describe a WordPress installation with a network of multiple blogs, grouped by sites. This installation type has shared users tables, and creates separate database tables for each blog (wp_posts becomes wp_0_posts). See also network, blog, site specific Compatibility
General Tips / Tricks / Notes (Ideally a tip or two from many different devs)
Adding Admin Notices
Giving your plugin the WordPress look (Hopefully the style guide will be finished before then).
Pluggable Functions
Admin Meta Boxes
Dashboard Widgets
Extending Tiny MCE
A Good Development Environment
Development Process

#3-org, #handbooks, #plugins

Mike Schinkel 8:25 pm on July 22, 2010

Wow, that’s an incredibly good list. Kudos.

I think that to improve that list will probably take just working on it to realize what’s missing but otherwise it’s incredible.
Rahul Bansal 8:30 pm on July 22, 2010

Such a handbook will be a real treat for pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party developers.
Being in business, I keep hearing from developers that wordpress codexWordPress Codex Living online manual to WordPress.org https://codex.wordpress.org/ is too primitive and wordpress lacks documentation a CMS need to win enterprise userbase.
I guess such handbook can fill that void.
Eric Marden 8:59 pm on July 22, 2010

I’d also cover functions.php. While a theme file, the techniques are largely the same.
- Aaron Jorbin 9:22 pm on July 22, 2010
  
  I think the eventual Theme dev handbook will cover that more (and will share alot of chapters/sections with this handbook)
  - Eric Marden 9:24 pm on July 22, 2010
    
    I think its a topic worth touching on in PluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party Dev Handbook, but covering fully in Theme Handbook.
  - Aaron Jorbin 9:27 pm on July 22, 2010
    
    How do you think it should be covered? What in do you think pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party devs need to know about theme functions.php files?
  - Mike Schinkel 9:31 pm on July 22, 2010
    
    For one, functions.php is a great place to start testing out proof-of-concept functionality that may be later moved into a proper pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party. Discussing that and the process of moving from proof of concept testing to actual plugin might be helpful.
  - Aaron Jorbin 9:50 pm on July 22, 2010
    
    I’ve added a section on development enviorment that could probobly cover that unless there is something else I am missing?
    
    I think I’m also going to add a Development Process section.
  - Mike Schinkel 9:58 pm on July 22, 2010
    
    Good idea. Elaborating, it would be nice to talk about setting up a local development environment on at least Windows, Mac OS X and generic Linux.
  - Eric Marden 10:00 pm on July 22, 2010
    I’d say that it should probably cover:
    
    The differences between functions.php and pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party files.
    
    What’s available and not available to you in functions.php
    
    When you should use it instead of a plugin
    
    Then point folks to the theme dev hand book.
  - Aaron Jorbin 4:55 am on July 23, 2010
    
    Eric – I think the first and the third parts would be good, I think the second is straying a bit too much into theme development and might be out of scope. This is designed to be one in a series of handbooks with the focus specifically on PluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party development. While a lot of the information within this handbook will also be in the theme developer handbook, I’d prefer it not confuse the two too much.
    
    Mike – That’s exactly what I meant by setting up a development environment. I imagine that section is going to be heavy on links and lighter on content though.
  - Eric Marden 2:26 pm on July 23, 2010
    
    Aaron – Sounds good to me. As long as their some mention of it, and pointers to more, I think it will help people avoid confusion and concur that you get into theme land pretty quickly when using the functions.php bridge.
    
    Mike – I agree with Aaron here, Dev Environment, while useful, is a bit out of scope. Pointing people to some good links is best, but this topic, I feel, should only be touched on in the scope of why its a good idea, not how to make it happen.
  - Mike Schinkel 2:35 pm on July 23, 2010
    
    @Eric: While not completely disagreeing I will say that the biggest “hump” I had to get over before I could finally be productive was getting a dev environment set up (I had been on Windows+ASP+IIS+SQL Server for 10+ years so LAMPLAMP LAMP is an acronym for Linux, Apache, MySql, PHP – a stack of free software programs that can function as the environment for running WordPress./WAMP/MAMP was all foreign to me.) After I finally was able to get help getting it all set up (3+ years ago, for Drupal at the time) I was rapidly able to gain relevant skills because each step was such a small step from the one before compare with the initial setup. I’ve also taught a lot of people WordPress over the past 2 years (~100 people) in workshop environments and the most important step for almost all of them is getting the development environment set up. So given how little one can do without it compared to with it and given how big a hurdle it can be to set up I would suggest we at least consider giving it more weight than we might otherwise give it if it were not such a critical path to productivity. JMTCW.
  - Eric Marden 7:22 pm on July 23, 2010
    @Mike
    
    While I don’t disagree that a local development environment is a huge boon to productivity and is an important topic, it starts to delve into the area of systems administration – one of the reasons I feel that a lot of new developers struggle with it, avoid it, or don’t even know they should or could have a local server. What I’m suggesting is limiting the topic to just the essentials and letting other sources deal with all of the other variables.
    
    In other words, it could look something like this:
    
    Here’s WAMP (windows)
    
    Here’s MAMP (mac)
    
    Here’s apt-get (linux)
    
    Here’s how to configure a VHOST to serve one WP site.
    
    As soon as we try to help them worry about multiple virtual hosts, the specifics of configuring ApacheApache Apache is the most widely used web server software. Developed and maintained by Apache Software Foundation. Apache is an Open Source software available for free., managing the /etc/hosts file for overriding DNSDNS DNS is an acronym for Domain Name System - how you assign a human readable address to a website’s exact numeric coded location (ie. wordpress.org uses the actual IP address 198.143.164.252). this topic soon becomes unwieldy and given that it is not essential for you to have one to develop a pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party we shouldn’t try to create even a shadow of a full blown HOWTO on the topic.
    
    Trust me, I’m the guy who has stepped in on a project and wouldn’t write a single line of code until the entire team got a local dev environment installed. But if there’s one thing I know about this topic is that getting the perfect set-up is almost impossible and the way they other guy did it is always “wrong”. Do I hand compile or use a package manager? Install binary components myself and tie them together in the configuration? A virtual machine with ubuntu? Or use a prepackaged all-in-one solution? Even the level of choice in this area, as you can see, can be overwhelming on its own and we haven’t even begun to tell you which steps to follow.
    
    Another reason to err on the side of simplicity (and letting other sources guide the users more deeply) is that anything put in this handbook will end up generating questions on the forums, #wordpress and wp-hackers and shouldn’t we really be in the business of supporting WordPress and not their (particular) local server?
    
    My 2 cents,
    
    ~e
  - Mike Schinkel 10:34 pm on July 23, 2010
    
    @Eric Fair points.
    
    One thing that I would personally like to see is it be _comprehensive; that would have helped me so much 2 years ago and I’d like to see others not have to go thru the same. If topics are collectively deemed as being too much of whatever then I’d argue at least that we cover the topic by curating a list of articles and solutions even if they point off WordPress.orgWordPress.org The community site where WordPress code is created and shared by the users. This is where you can download the source code for WordPress core, plugins and themes as well as the central location for community conversations and organization. https://wordpress.org/. Then, for example, we could find a multiple VHOST article that covers concerns related to WordPress or if one can’t be found then one of us could write one on our blogblog (versus network, site) and link to it. FWIW multiplier VHOSTs were one of the more difficult things to figure out yet one of the ones I cannot image being without today. Ironically it was really not difficult, I just had to learn a few arcane details. those details would make a great article.
    
    As for the other comment you made let me relate a story and I apologize that it is off topic for the develop handbook. Shortly after graduating college, probably 1992 I attended a presentation to entrepreneurs where the message hit home and has stuck with me for my adult like. In a nutshell the person made the point that if you have something you are “selling” (in our case we are all advocating for WordPress) then it is in your win best interest to make sure the prospective customer has as easy a time being able to acquire and use your solution as possible. If there is anything that would cause prospects to stall and go elsewhere, or simply not “purchase” at all then it is incumbent upon you to handle that problem for them or at least make the problem appear to go away.
    
    So yes one can argue that we want to support WordPress only and not help people with their server setups and from a standpoint of purity you would be right. OTOH if we in fact do care about seeing a lot more people adopt WordPress then such perspective may be self-defeating. Note that the solution may not always be to “brute force” it but instead may be to divide and conquer (i.e. maybe we solve the problem by working with web hosts to minimize the problems, educate prospective users on which hosts have the least problems and then provide support for the remaining.) JMTCW.
  - Tim 10:54 pm on July 23, 2010
    
    Discussion of Dev Environments, to some degree, would be good. Rather than focusing on specific environments, maybe a better way to approach this section in the handbook would be to encourage standardized ways of reporting what versions of WordPress (version number and single vs. Multi-Site testing), PHPPHP The web scripting language in which WordPress is primarily architected. WordPress requires PHP 5.6.20 or higher and MySQLMySQL MySQL is a relational database management system. A database is a structured collection of data where content, configuration and other options are stored. https://www.mysql.com/. a pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party has been tested on. Right now, there’s a “tested up to” tagtag A directory in Subversion. WordPress uses tags to store a single snapshot of a version (3.6, 3.6.1, etc.), the common convention of tags in version control systems. (Not to be confused with post tags.) in the plugin headerHeader The header of your site is typically the first thing people will experience. The masthead or header art located across the top of your page is part of the look and feel of your website. It can influence a visitor’s opinion about your content and you/ your organization’s brand. It may also look different on different screen sizes., but there isn’t a consistent way to report PHP/MySQL version requirements.
    
    Or perhaps this belongs in a new section covering “Writing a good readme file”?
  - Matt 11:07 pm on July 23, 2010
    
    Small handbooks, loosely joined.
  - Aaron Jorbin 1:57 am on July 24, 2010
    
    Anything more then a passing reference is going to be too much. I don’t want this devolving into a 800 page coffee table book that no one actually reads.. It’s for WordPress PluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party Development, not system administration. Perhaps there will be another book focused on that.
Eric Marden 9:00 pm on July 22, 2010

Also don’t forget to talk about nonces. Probably under security and/or options pages.
- Aaron Jorbin 9:23 pm on July 22, 2010
  
  Thanks I knew I would miss something.
Denis 9:05 pm on July 22, 2010

I think you’re missing an important bit: the WP flow, with an outline of the hooksHooks In WordPress theme and development, hooks are functions that can be applied to an action or a Filter in WordPress. Actions are functions performed when a certain event occurs in WordPress. Filters allow you to modify certain functions. Arguments used to hook both filters and actions look the same. and when they occur, in what order, what they’re used for, etc. And most importantly, how to not interfere with other plugins on the same hook… (eg never call remove_action(myhook, myfunc) on myhook.)
- Aaron Jorbin 9:26 pm on July 22, 2010
  
  I think the APIAPI An API or Application Programming Interface is a software intermediary that allows programs to interact with each other and share data in limited, clearly defined ways. reference is going to more so cover flow. The actions section will definitely cover proper use of actions and priority.
Eric Marden 9:25 pm on July 22, 2010

Media probably covers this a bit, but overriding the javascriptJavaScript JavaScript or JS is an object-oriented computer programming language commonly used to create interactive effects within web browsers. WordPress makes extensive use of JS for a better user experience. While PHP is executed on the server, JS executes within a user’s browser. https://www.javascript.com/. send_to_editor was a recent find of mine and is worth covering. I’m guessing there are other Javascript ‘hooksHooks In WordPress theme and development, hooks are functions that can be applied to an action or a Filter in WordPress. Actions are functions performed when a certain event occurs in WordPress. Filters allow you to modify certain functions. Arguments used to hook both filters and actions look the same.’ (timymce stuff?).
- Eric Marden 9:26 pm on July 22, 2010
  
  err… tinymce
- Aaron Jorbin 9:47 pm on July 22, 2010
  
  Thanks. Good catches. Please, keep them coming.
Aaron Jorbin 9:48 pm on July 22, 2010

Added:
Pluggable Functions
Adminadmin (and super admin) MetaMeta Meta is a term that refers to the inside workings of a group. For us, this is the team that works on internal WordPress sites like WordCamp Central and Make WordPress. Boxes
Dashboard Widgets
A Good Development Environment
- Eric Marden 10:09 pm on July 22, 2010
  - PHPPHP The web scripting language in which WordPress is primarily architected. WordPress requires PHP 5.6.20 or higher Docblocks
  - Licensing and Distribution
  - Promoting your PluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party
  - Best Practices with JSJS JavaScript, a web scripting language typically executed in the browser. Often used for advanced user interfaces and behaviors./CSSCSS Cascading Style Sheets. (like not using !important in your CSS, etc)
  - PHP Best Practices ( i.e. Coding with E_ALL on, avoiding common Notices/Warnings)
  - SVNSVN Subversion, the popular version control system (VCS) by the Apache project, used by WordPress to manage changes to its codebase.
  - Releasing your Plugin on WP.org
  - ReadMe.txt and plugin comment headerHeader The header of your site is typically the first thing people will experience. The masthead or header art located across the top of your page is part of the look and feel of your website. It can influence a visitor’s opinion about your content and you/ your organization’s brand. It may also look different on different screen sizes.
  - Data Import/Export
  - Migrations (WP_RELOCATE)
  Obviously we’re getting into the minutiae now, and some of this stuff can be and probably is implied by some of what’s above, but thought I’d offer them up anyway. Also some of this may be running into other hand book territory.
  
  Is this going to be collaboratively written, and if so where and on what platform?
  - Aaron Jorbin 4:59 am on July 23, 2010
    
    I’m not sure if migrations would really fall under the purview of a pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party developer. I think that might fit better for a WordPress administrator book.
    
    For Import/Export, I assume you mean import/export of plugin data. Correct?
  - Ryan McCue 1:12 pm on July 23, 2010
    
    Apologies for the off-topic reply, but what precisely is WP_RELOCATE? I can’t find a reference to it anywhere in code, and there’s only one reference to it on wp-hackers.
- Eric Marden 2:33 pm on July 23, 2010
  
  Ryan – sorry its RELOCATE, documented here: https://codex.wordpress.org/Changing_The_Site_URL#Relocate_method
  
  Aaron – You may be right. I continue to suggest things from a more holistic WP Developer mind set. Maybe we need a handbook that integrates adminadmin (and super admin), theme, and pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party from a top down approach, where these topics so far have been a bit more ground up. (small component effecting larger whole).
Mike Schinkel 10:01 pm on July 22, 2010

Floating an idea. This could turn out to be a killer book if packaged as such, and might catch interest if available at major bookstores from people who might not otherwise dig into the topic. What about coordinating with a major publisher where the proceeds go to the WordPress Foundation? Again, just an idea to consider.
- Matt 10:44 pm on July 22, 2010
  
  We can cross that bridge when we get there. I wish all of the WP books thus far had been under an OS license but most authors aren’t going to have that sort of leverage with their publisher. I had one tell me “books are hard, why would we allow anyone to take the content!” Yes, ma’am, software is hard too. 🙂
  
  Now we’re completely off-topic, but here’s a link everyone should read:
  
  http://diveintomark.org/archives/2009/10/19/the-point
  - Mike Schinkel 11:12 pm on July 22, 2010
    
    Yep, the idea is definitely premature but I figured it would be better to have in the back of our minds if doing so was an option. FWIW.
  - Stephen R 3:05 am on July 25, 2010
    
    There’s an SVNSVN Subversion, the popular version control system (VCS) by the Apache project, used by WordPress to manage changes to its codebase. book that is… not sure if it’s open sourceOpen Source Open Source denotes software for which the original source code is made freely available and may be redistributed and modified. Open Source **must be** delivered via a licensing model, see GPL. but they givve it away for free on the web site, or you can buy the physical book from O’Reilly. S not totally without precedent in books.
mercime 5:31 am on July 23, 2010

PluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party which create table/s in DB to add Uninstall function
Cheers
- Aaron Jorbin 11:53 am on July 23, 2010
  
  That is part of the reason that people will be encouraged to use the existing data structures whenever feasible, but yes, that will be a part of custom tables.
João Pedro Pereira 10:21 am on July 23, 2010

Excelent list, Nothing to add besides TEST, TEST, TEST!
arena 11:39 am on July 23, 2010

Hi ! your list lacks structure.

Most of the topics are related to the numerous wp api’s

i would add the following topic
. adminadmin (and super admin) (menus, admin pages, clean coding (not loading js or css if current admin page is not related to pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party))
- Aaron Jorbin 12:00 pm on July 23, 2010
  
  Actually it does have structure, it’s an unordered list with list items that sometimes contain unordered lists 🙂
  
  For menus, I assume you are referring to interacting with the new nav menu items?
  
  Clean coding will certainly be a part of the WP coding standards and proper use of wp_enqueue_script / style (i.e. adding it to the right hook) will definitely be a part of the adding styles and scripts section.
  - arena 4:20 pm on July 23, 2010
    
    i was refering to adminadmin (and super admin) menus
filosofo 3:31 pm on July 23, 2010
Who is the proposed audience, and what do you see as the niche for this document in a world of grep, googling, and the Codex? It would be good to determine that before investing too much time in the wrong topics or too many details.

Languages of WP – Differences between PHPPHP The web scripting language in which WordPress is primarily architected. WordPress requires PHP 5.6.20 or higher, HTMLHTML HyperText Markup Language. The semantic scripting language primarily used for outputting content in web browsers., CSSCSS Cascading Style Sheets., JSJS JavaScript, a web scripting language typically executed in the browser. Often used for advanced user interfaces and behaviors.

I don’t know the exact intended audience, but if it’s “developers” by any reasonable definition it should exclude someone who doesn’t know the difference between PHP and JS. That person needs to be doing remedial programming–maybe read Master PHP in 24 Hours or whatever—first.
- Adminadmin (and super admin) MetaMeta Meta is a term that refers to the inside workings of a group. For us, this is the team that works on internal WordPress sites like WordCamp Central and Make WordPress. Boxes
- Dashboard Widgets
- Extending Tiny MCE
I suspect that’s the kind of detail that won’t do any potential audience much good. If you’re at the place that you’re ready to extend TinyMCE, you’re just going to google how to do it. If you’re new to WordPress pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party development, being blasted by a firehose of details will probably impress upon you the potential of WP, but it’s unlikely most of those details will stick. Or worse, the wrong details will stick to the detriment of more important ones.

My suggestions: make the audience to comprise those with a reasonable knowledge of PHP, MySQLMySQL MySQL is a relational database management system. A database is a structured collection of data where content, configuration and other options are stored. https://www.mysql.com/., and JS; neither beginners nor those who have an advanced knowledge of WP in particular. The former need more than you could possibly provide, and the latter don’t need your help.

And don’t think of it as an academic course, in which someone can dedicate a semester to studying every topic. That’s not how most developers with jobs learn. Instead, pick a few truly coreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress. concepts, the ones that are necessary and sufficient to getting a typical plugin running. Then you can let code examples hint at some of the other details: they will be enough to spark interest without making the reader feel unduly burdened.
- Eric Marden 7:31 pm on July 23, 2010
  
  @filosofo
  
  I think that this pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party should serve more than just beginners. Even a mention of what’s possible (by covering all of the various extension points in WP) and cross linking to the function reference in the Codex will be a huge help to all developers, beginners and advanced alike. I, for one, am a bit sick of having to grep the code base just to look up a function signature or having to trace the code to discover that there is an undocumented filterFilter Filters are one of the two types of Hooks https://codex.wordpress.org/Plugin_API/Hooks. They provide a way for functions to modify data of other functions. They are the counterpart to Actions. Unlike Actions, filters are meant to work in an isolated manner, and should never have side effects such as affecting global variables and output. buried in the middle of one of the functions that get called – the exact filter I need to write my plugin cleanly. I kind of see this handbook as a part comprehensive overview and part getting started guide.
  
  However, I do agree that a discussion on the difference between various languages and technologies used in the construction of a WP plugin is unwarranted and does provide a small barrier to entry for this part of the docs. Right now all the Codex has is this: “WARNING: Programming Code Ahead!” or something like that.
  - filosofo 7:43 pm on July 23, 2010
    
    I think that this pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party should serve more than just beginners. Even a mention of what’s possible (by covering all of the various extension points in WP) and cross linking to the function reference in the Codex will be a huge help to all developers, beginners and advanced alike.
    
    Well, I guess it really depends on what the purpose of the handbook is supposed to be (its niche). To me what you’re describing sounds more like an annotated index of the Codex, or maybe even just the Codex already. That would seemingly be only a quantitative, not qualitative change from what’s already available.
  - Aaron Jorbin 2:25 am on July 24, 2010
    
    @filosofo
    I view this as being a compliment to the APIAPI An API or Application Programming Interface is a software intermediary that allows programs to interact with each other and share data in limited, clearly defined ways. reference, but more focussed on Narrative explanations and explaining full API sections. While the API reference will tell you that register_taxonomy is used to create or modify a taxonomyTaxonomy A taxonomy is a way to group things together. In WordPress, some common taxonomies are category, link, tag, or post format. https://codex.wordpress.org/Taxonomies#Default_Taxonomies. object, and what arguments it takes, the handbook will explain what you can do with that taxonomy after it’s created.
    
    Will someone like you, who has a deep knowledge of the code turn to the handbook first? Doubtful. I imagine you’ll find what you need in the code. Might you turn to it if you have never used the HTTPHTTP HTTP is an acronym for Hyper Text Transfer Protocol. HTTP is the underlying protocol used by the World Wide Web and this protocol defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. api and want to get an idea of some best practices and a understanding of how you can use that in concert with Simple pie? Perhaps. Will someone building there first through fourth pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party find it useful? Absolutely.
    
    The reason I have the differences between languages is in part to help weed out the people that aren’t willing to learn more. I don’t view that as being as very long section. I imagine it being similar to http://aaron.jorb.in/blog/2010/01/you-better-know-the-basics/ , but better written. Then a simple: “Not scared to continue? Well onward to Victory!”
    
    For some of the sections (like TinyMCE editor), I actually think it might be best to keep it simple and point them to a small handfull of plugins that are doing it so that they can read some actual code. That’s open for thought though
jeremyclarke 4:56 pm on July 23, 2010

This looks great!

It’s a small detail, but It seems to me that the “Actions/Filters” section should come before “Adding Styles and Scripts”. As far as I know, adding styles/scripts is done through the APIAPI An API or Application Programming Interface is a software intermediary that allows programs to interact with each other and share data in limited, clearly defined ways. so knowing how the API works first is probably a good investment 😉

I’m pretty sure you would have changed it during the writing but figured I’d mention it as an excuse to tell you the list looks great and I’m excited for the result 🙂
- Aaron Jorbin 3:55 am on July 26, 2010
  
  The order above was in no way meant to imply the order the chapter would actually come in. It’s more so the order I brainstormed them in.
Jacob Santos 8:35 pm on July 23, 2010
It would be better to organize it in two or three sections.
- PluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party System
- How to Develop
- WordPress Library Guides
The Plugin System should include the introduction, what filters and actions are, how they work, how to add action and filters. Why and how they might be added to your themes and plugins.

How to develop section should include WordPress coding standardsWordPress Coding Standards The Accessibility, PHP, JavaScript, CSS, HTML, etc. coding standards as published in the WordPress Coding Standards Handbook.
May also refer to The collection of PHP_CodeSniffer rules (sniffs) used to format and validate PHP code developed for WordPress according to the PHP coding standards., Subversion, WordPress Extend, adding plugins, checking out, how to work with the support and TracTrac An open source project by Edgewall Software that serves as a bug tracker and project management tool for WordPress. Ticketing. Could also include notes on PHPPHP The web scripting language in which WordPress is primarily architected. WordPress requires PHP 5.6.20 or higher docblocks, unit testing, and general ui testing.

The WordPress Library Guides will include the large portion of the guide which would include every individual APIAPI An API or Application Programming Interface is a software intermediary that allows programs to interact with each other and share data in limited, clearly defined ways. section in WordPress and WordPress Adminadmin (and super admin).
- Aaron Jorbin 3:59 am on July 26, 2010
  
  My next step is actually to synthesize all this feedback and try to come up with a more coherent outline. What you’re proposing is pretty similiar to what I have in mind. Thanks Jacob!
bentrem 2:08 am on July 24, 2010

Are you setting up to co-author? Cuz I’ve been following DAV since *blush* a long time (see MozDawg on DAV and Docs, notes for which I started shortly after Netscape “released the code”.) Reason I ask: however slow the progress, progress there’s been. Now my first instinct was to shout out “This is a good start on a wiki page!” but I choked it back with something like, “Yaaa … yet.another dusty bit-rotted wiki page”.
Social dynamics.
Too bad GWave and GBuzz suck so completely when operationalized.
p.s. I got started Analogous Techniques next month but my “army of 1” batteries are flat / dead.
Stephen R 3:10 am on July 25, 2010

I think this is a really excellent idea. Part of the problem is making sure it will be updated over time and not grow stale == a problem oftentimes in Codex.

Something you might add: a section on “final polish” — little things like adding the “Setup” link from the Manage Plugins page straight to your settings page. There are lots of little useful touches that aren’t purely coreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress. function of the pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party, but just make it a lot nicer in the details.
- Aaron Jorbin 4:01 am on July 26, 2010
  
  That tip is one that I think would be perfect for the General Tips / Tricks / Notes section. At a later date and time I’ll solicit those.
Ramon Fincken 1:30 am on July 26, 2010

Nice!

Perhaps handy:
Scheduled events (pseudo-cron) + Ajax frontend > http://www.ramonfincken.com/permalink/topic187.html
Mike Schinkel 3:42 am on July 27, 2010

I see you have transients (Transients APIAPI An API or Application Programming Interface is a software intermediary that allows programs to interact with each other and share data in limited, clearly defined ways.?[1]) but I don’t see any reference to the Settings API[2]?

[1] https://codex.wordpress.org/Transients_API
[2] https://codex.wordpress.org/Settings_API
- jeremyclarke 3:01 pm on July 28, 2010
  
  I think he just didn’t refer to it as the Settings APIAPI An API or Application Programming Interface is a software intermediary that allows programs to interact with each other and share data in limited, clearly defined ways. but he has:
  
  Options
  * Adding options to existing adminadmin (and super admin) pages
  * Adding your own pages
  
  I think the first one would be the Settings API. Though its a good point that the section about adding settings pages should refer to the Settings API by name so that its brand is strengthened.
Byron 3:34 am on July 28, 2010

This Handbook is badly needed. It could seriously raise the average quality of WordPress plugins (my own could have benefitted tremendously when I start out a year-and-a-half ago). If it wasn’t for Vladimir Prelovac’s pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party book, I’d still be trying to start fire with sticks. Will this be open to contributors?
Jeff Sayre 3:04 pm on July 28, 2010

Aaron –

Have you seen my article on WordPress action and filter events (hooks)? It could be useful for part of the information in the section on this subject. I have also created a pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party developers’ tool called the WordPress Hook Sniffer plugin. I just released an updated version this morning.
Marjorie Roswell 1:03 pm on September 17, 2010

Some questions that come to mind: Where should we look for the handbook? Online? In print? When? Will the handbook be available in draft form as its being developed?

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