plugin-development - Read For Learn

Any examples of adding custom fields to the category editor?

No. You have to use wp_options, because you can’t create new fields in the wp_term_taxonomy table (If you do, in the next WP update you’ll loose them). So: // the option name define(‘MY_CATEGORY_FIELDS’, ‘my_category_fields_option’); // your fields (the form) add_filter(‘edit_category_form’, ‘my_category_fields’); function my_category_fields($tag) { $tag_extra_fields = get_option(MY_CATEGORY_FIELDS); ?> <table class=”form-table”> <tr class=”form-field”> <th scope=”row” valign=”top”><label … Read more

Does a plugin’s “main” file need to be named the same as the folder containing it?

Simple answer, NO. The plugin file can be named anything you want as long as at the very top of it you include the plugin Meta (name, description. …)

How to provide translations for a WordPress TinyMCE plugin?

Use the filter ‘mce_external_languages’. From wp-includes/class-wp-editor.php: The following filter loads external language files for TinyMCE plugins. It takes an associative array ‘plugin_name’ => ‘path’, where path is the include path to the file. The language file should follow the same format as /tinymce/langs/wp-langs.php and should define a variable $strings that holds all translated strings. When … Read more

How to create a WordPress plugin for another wordpress plugin?

I think best way to do this is via actions and filters, like we extend WordPress core itself. Other options is like @helgatheviking pointed, if plugin is class you can extend it. Unfortunately not all plugin developers provide useful filters and actions with their code, most often plugin isn’t written in OOP manner. Only way … Read more

What is wrong with using add_option with Multisite instead of add_blog_option in a plugin

add_blog_option ultimately calls add_option itself to add the option after switching the context to the supplied blog ID. the difference is that add_option will only work in the context of the current blog where add_blog_option lets you specify a blog ID that may be different than the current context.

Using composer for dependency management in plugindevelopment

There are still very few WP plugins/themes that are being developed Composer-first. You can take a look at Laps case study (one of mine) for practical example. Essentially if you plan for plugin to be publicly distributed you need to take care of both cases – running it as part of whole-site Composer stack and … Read more

Overwrite theme file from plugin

WordPress way (recommended): In your plugin, use the WordPress theme_file_path filter hook to change the file from the plugin. Use the following CODE in your plugin: add_filter( ‘theme_file_path’, ‘wpse_258026_modify_theme_include_file’, 20, 2 ); function wpse_258026_modify_theme_include_file( $path, $file=”” ) { if( ‘includes/example-file.php’ === $file ) { // change path here as required return plugin_dir_path( __FILE__ ) . … Read more

How to implement add_image_size in a plugin

Just call this function in the init action. This action is fired for both frontend and backend. So it should look like this: add_action( ‘init’, ‘wpse4378_add_new_image_size’ ); function wpse4378_add_new_image_size() { add_image_size( ‘wp_small’, 60, 75, true ); //mobile }

Which action for triggering cron “wp”or “init”?

Neither. register_activation_hook( __FILE__, ‘trigger_me’ ); function trigger_me() { if ( !wp_next_scheduled( ‘my_plugin_cron’ ) ) { wp_schedule_event(time(), ‘hourly’, ‘my_plugin_cron’); } } Why parse code on every request when you don’t need to?

Checking if an attribute exists in a shortcode

Okay, I’ve re-written the function so that it does the following: checks that your array values are set before using them. You can’t always be sure they’ll be there. if the image is empty, it returns with an error message. Not sure if this is what you want, but you can just remove it. first … Read more

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