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This is just a quick note for anyone who runs into the same issue. If you use wp.editor.initialize() to dynamically create an instance of the WordPress visual editor, the editor will be missing the “Add Media” button by default. To fix that, you need to do two things: 1. Add mediaButtons: true to the setting […]

I’ve made a site that shows actions and filters executed during different WordPress requests. Why? When I’m writing a plugin, I sometimes need to know not just what a hook does, but also when it runs in relation to other hooks. The official WordPress documentation has a list of common actions, but it’s out of […]

Ever since the release of the Plugin Update Checker library, one of the most common questions asked has been this: “How can I secure my download links so that only users who have purchased my plugin can download an update?” In this post I’ll try to answer that question in the context of using WP […]

It’s been a long time coming, but I’ve finally released an external update API server for WordPress plugins and themes. Check it out on GitHub. This is the server component to my plugin update checker and theme update checker client libraries. Features Provide updates for private or commercial plugins and themes. From the users’ perspective, the […]

Lets say you have a category called “X”, and you want to create a link which when clicked will take the user to the “Add New Post” screen with the “X” category already selected. This could be used to simplify posting for non-technical users, or even as a way to implement “poor-man’s custom post types” […]

One thing that many developers are not aware of is that WordPress automatically adds magic quotes to request variables. This means that all quotes, backslashes and null-byte characters will be escaped with a backslash. Even if you disable magic quotes in php.ini, WordPress will apply them to $_GET, $_POST, $_COOKIE and other superglobals anyway. If […]

JSONLint – Validate Your JSON JSONLint is an online JSON validator and formatter. It will check your JSON for syntax errors and format it with proper indentation and line breaks to make it more human-readable (this can be very handy when analysing complex JSON documents). You can either paste your JSON data in the form […]

After a long delay, a new version of my PluginUpdateChecker library is finally ready for release. Read on to find out what’s new, or go straight to the download page. For those of you not familiar with this library, here’s a short summary: You can use it to add automatic update support to any WordPress plugin. Especially […]

There’s one thing that always annoys me when installing new plugins: No matter how popular or obscure the plugin, the first few seconds (or minutes) are usually wasted on trying to figure out where it put its settings page. We’ve all been there. Trawling the admin menu, looking for that elusive link that will actually […]

As you may already know, WordPress stores top-level menus in a global $menu array. The array indexes correspond to menu positions, and each array item contains the properties of a single menu – the menu title, required capability, URL, and so on. Separator items are structured just like normal menus, except they also have a […]

You can use the undocumented all_plugins filter to control what plugins will show up on the “Plugins” page. WordPress applies this filter to the list of all installed plugins just before sorting it into “active”, “inactive”, “update available” and other categories and displaying it to the user. The list of plugins is an array indexed […]

WordPress Console Adds an interactive PHP console (REPL) to the WordPress admin. You can run arbitrary PHP code and access any function, class or variable defined by WordPress or active plugins. Amazing for debugging and exploration. Note: At the time of this writing, the plugin directory listing says this plugin is only “compatible up to […]

Add your hook before or after another hook Sometimes you need to ensure your function will get executed before or after another function that’s attached to the same hook (e.g. to fix a plugin conflict). The most reliable way to do this is to use has_action() to get the priority of the other hook and […]

I had some free time this weekend, so I built an automatically updated list of Top 100 WordPress plugin developers. The rankings are based on the number of times each developers’ plugins have been downloaded from the WordPress.org plugin directory. A short PHP script updates the list several times per day. Check it out. Bonus: Compare […]

If you’re at all familiar with WordPress development, you already know how to remove a normal hook: just call remove_action or remove_filter and pass it the hook name, the name of the hook callback you want to remove and the priority. But what if the callback has no fixed name because it’s an anonymous function […]

Today I bring you 20+ handy built-in WordPress functions. Some of them you may already know and use every day, while others you’ve probably never heard of as they’re usually not mentioned in WP tutorials or even the WordPress Codex. Being aware of these functions and knowing how to use them will save you time […]

tldextract.php is a PHP library that accurately extracts the effective top-level domain name, registered domain and subdomains from a URL. For example, you can use it to get the domain name “google” from “http://www.google.com”, or the TLD “co.uk” from “http://www.bbc.co.uk/”. Example: Introduction Most people try to do this by splitting the domain name on ‘.’ […]

Chances are, you’ve run into this WordPress error at one time or another: That’s a pretty unhelpful error message, isn’t it? Not only does it tell you nothing about what the exact problem is or how it occurred, but it’s also sometimes just plain wrong. Pretty often, it has nothing to do with insufficient permissions. […]

For all your theme testing and plugin development needs, here’s a huge list of WordPress sample content collections and dummy content generators. Export Files See How to import WordPress export files for instructions on how to import the files listed in this section on your site. Theme Unit Test Data from WordPress.org 22 Posts Sticky post […]

If you’re a WordPress developer, this will probably sound familiar: you make a change to  one of your scripts or style sheets, reload the page you’re working on to see the result, and… everything stays the same. Of course, after a moment of confusion, you realise that you didn’t update the $version argument in your […]

The built-in json_encode() function in PHP puts everything on one line. For development and debugging, it can often be more useful to have properly indented, human-readable JSON that makes it easier to manually inspect the encoded data and check it for problems. Here’s a function that lets you format/pretty-print any JSON string to be more […]

As you probably know, you can use the add_menu_page() function to create a top level admin menu for your WordPress plugin or theme. This function allows you to specify a menu icon by passing an image URL as the $icon_url argument. But what if you want to use one of the default admin icons – […]

For plugin developers desiring an easier way to perform common tasks, a little more structure in their code, or perhaps even a dash of MVC goodness, here is a list of WordPress plugin frameworks. This list is intended to be comprehensive. If you find an actively maintained plugin framework that’s not listed here, let me […]

It’s time for another WordPress plugin development tutorial 🙂 In this post, I will provide a step-by-step explanation of how to create a WordPress plugin that lets the user add an automatically generated table of contents (TOC) to their posts by using a simple shortcode. The completed plugin will support the following syntax: For example, […]

As of WordPress 3.1.3, it’s really easy to prevent unscrupulous web developers from displaying your site in a frame. Just add this one-liner to your functions.php file: Now any other site that tries to load your WP blog in a frame will get this instead: (The actual error message will vary depending on the browser. […]

I wanted to familiarize myself with the much-touted canvas element, so I used it to build an interactive celtic knot generator/editor. Give it a try. Launch the celtic knot generator. Note: Requires a fairly modern browser. Instructions When you first load up the knot generator, you will see a 10×10 grid filled with the default […]

You’ve probably seen the small notification bubble that shows up in the Dashboard menu when a new update is available. Here’s how you can add a menu bubble to your own custom menu: The resulting menu will look like this:

Plugins are usually loaded and executed along with the rest of WordPress. However, since each plugin is physically just set of .php, .css and .js files, it is also possible for someone to bypass the normal load order and execute the plugin files directly.  They just need to type the right URL in the address […]

WordPress transients are very similar to DB options but they also support expiration times. The Transients API documentation states: Our transient will die naturally of old age once $expiration seconds have passed since we last ran set_transient() What you might not know if you haven’t explored the source code of the transients API is that […]

Recently, I found this old question on WordPress StackExchange: I am starting a new WordPress blog, and no longer updating an old one. […] How can I lock the installation of WordPress down so I don’t need to maintain it? I have seen someone suggest making a static version, which sounds like a lot of […]