Plugins, Hooks (category)
| activate_plugins() | Activates the specified plugins. |
| add_screen_option() | Registers an option for an admin page that will be shown in the special "Screen Options" tab (in the top right corner). |
| content_url() | Gets the URL to the content directory (folder wp_content) without a slash (/) at the end. Considers the protocol (https). Takes into account sub-sites if multisite is used. |
| deactivate_plugins() | Deactivates the specified plugins. You can specify deactivation parameters. |
| get_file_data() | Gets the file data specified in the PHP comments of the file. |
| get_plugin_data() | Gets plugin data (specified in the headers) from the given path to the main plugin file. |
| get_plugins() | Gets all plugins data (active and inactive): file, name, author, etc. Works with the plugins directory. |
| is_plugin_active() | Determines whether a plugin is active. Works in the dashboard only. Conditional tag. |
| plugin_basename() | Gets the relative path to the main plugin file (from the plugins or MU plugins directory) based on the provided file path. |
| plugin_dir_path() | Gets the full path to the folder where the specified file - __FILE__ is located. With a slash at the end. |
| plugin_dir_url() | Gets the URL of the folder (with a slash at the end) where the specified plugin file is located. |
| plugins_url() | Gets the URL of the plugins or mu (must use) plugins folder (without a trailing slash). |
| register_activation_hook() | Registers a function that will be triggered at the time of plugin activation. |
| register_deactivation_hook() | Registers a function that will be executed after the plugin is deactivated. |
| register_uninstall_hook() | Registers a function that is called when the plugin is deleted to clean up all traces of the plugin in the system. |
| validate_plugin_requirements() | Checks that the current plugin meets the necessary requirements for PHP version, WordPress, and active dependent plugins. |
| wp_get_active_and_valid_plugins() | Gets an array of paths to the main files of active plugins. |
Hooks (actions, filters)
| add_action() | Hooks a function on to a specific action. |
| add_filter() | Attaches the specified PHP function to the specified filter hook. Thus, when the filter is triggered, the value will be filtered by the specified PHP function. |
| apply_filters() | Applies the attached PHP function to the specified filter. |
| apply_filters_ref_array() | Executes the functions attached to the specified hook (filter). Parameters are passed in an array. Allows passing a parameter by reference. |
| current_filter() | Gets the name of the current filter. |
| did_action() | Retrieve the number of times an action (hook) is fired. |
| do_action() | Creates an event (a hook for a php function). For the function to work during the action, it should be added to this action with add_action(). |
| do_action_ref_array() | Creates an action (hook) on which PHP functions can then be attached. The arguments are passed as an array. |
| doing_action() | Checks whether the specified hook (filter, action) is currently being processed. |
| doing_filter() | Checks whether the specified hook (filter, action) is currently being processed. |
| has_action() | Checks if a function has been registered for the event hook. |
| has_filter() | Checks if any function is attached to the specified filter. You can specify the name of a specific function. |
| remove_action() | Removes a hook (event or filter). Removes the function attached to the specified hook. |
| remove_all_actions() | Removes all hooks for the specified event. |
| remove_all_filters() | Removes all hooks from the specified filter. |
| remove_filter() | Removes a function from a specified filter hook. |