Using Actions and Filters in WordPress to Make a Plugin Your Own
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The document discusses how to customize WordPress plugins using actions and filters, providing key examples of both. It outlines methods for finding applicable hooks within a plugin and emphasizes the importance of documentation and community resources for support. The document encourages users to reach out to developers or utilize support forums when unable to locate specific actions or filters.
![Actions
do_action( $identifier, [ $arg1, $arg2, ... ] )
add_action( $identifier, $function_name, [ $priority, $arg_count ] )](https://image.slidesharecdn.com/wordcamptoronto2015actionsfilterswordpressplugins-151001183656-lva1-app6892/85/Using-Actions-and-Filters-in-WordPress-to-Make-a-Plugin-Your-Own-6-320.jpg)
![Filters
apply_filters( $identifier, $value, [ $arg1, $arg2, ... ] )
add_filter( $identifier, $function_name, [ $priority, $arg_count ] )](https://image.slidesharecdn.com/wordcamptoronto2015actionsfilterswordpressplugins-151001183656-lva1-app6892/85/Using-Actions-and-Filters-in-WordPress-to-Make-a-Plugin-Your-Own-8-320.jpg)
Using Actions and Filters in WordPress to Make a Plugin Your Own
- 1. Making a Plugin Your Own Using Actions and Filters in WordPress Brian Hogg brianhogg.com | @brianhogg WordCamp Toronto 2015
- 6. Actions do_action( $identifier, [ $arg1, $arg2, ... ] ) add_action( $identifier, $function_name, [ $priority, $arg_count ] )
- 7. Actions (Example) do_action( 'the_plugin_action' ); function handle_the_plugin_action() { echo 'The action is happening now!'; } add_action( 'the_plugin_action', 'handle_the_plugin_action' );
- 8. Filters apply_filters( $identifier, $value, [ $arg1, $arg2, ... ] ) add_filter( $identifier, $function_name, [ $priority, $arg_count ] )
- 9. Filters (Example) echo apply_filters( 'plugin_title', 'Title' ); function change_plugin_title( $title ) { return 'New Title'; } add_filter( 'plugin_title', 'change_plugin_title' );
- 10. Filters (Example) echo apply_filters( 'plugin_title', 'Title' ); function change_plugin_title( $title ) { return 'New ' . $title; } add_filter( 'plugin_title', 'change_plugin_title' );
- 11. How do you find what you can change in a plugin? Search for do_action and apply_filters
- 12. The Events Calendar Plugin •apply_filters •442 occurrences •do_action •190 occurrences
- 13. How to Find The One You Need? ▪ Look at the plugin documentation (if any) ▪ Look at the code ▪ Look at the HTML output and backtrack
- 14. DEMO
- 15. The Events Calendar ▪ Message to verify location ▪ Venue -> Location ▪ Cost formatting
- 16. Can’t find the one you need? ▪ (Nicely) ask the developer of the plugin ▪ Direct contact information / website ▪ wordpress.org support forums ▪ Look for a paid support or Pro version ▪ Submit a patch
- 17. Go make plugins your own!
Editor's Notes
- #6: ACTION An action is something that is fired at a specific point in time, and basically tells the WordPress world “hey! something's happening right now”. FILTER A filter allows you to modify some data or value the plugin is going to use. You can either change parts of a value, or replace it completely, before the plugin actually uses it.
- #7: Actions and filters are very similar in their usage. For an action, a plugin author would call do_action with a unique identifier, and optionally some extra arguments related to the action. In our code we can then create a call to add_action(), which would call a function we create when this action is fired. The first argument is the same unique identifier used in do_action, and the name of the function we want WordPress to call. Optionally we can specify the priority of our function being called relative to others who are hooking into the same action, and the number of arguments we want to pass into our function from the do_action call.
- #9: Filters work by the plugin calling apply_filters, with a unique identifier and the default value or data the plugin wants to use. Optionally extra information can be passed in to help us decide how to change the value, such as the current post ID. In our code,
- #15: Go forth and modify plugins using actions and filters
- #17: So what if, after looking for documentation, looking at the code and using the search for HTML technique, you still can’t find a filter or action you can use? You can (nicely) ask the developer either directly if they provide a website or contact information, or through the support forum on the wordpress.org plugin page, for what you’re looking for. They might add it for you if it doesn’t exist already, or let you know where to find what you’re looking for. Try to be succinct and specific in your request, and remember that often plugins are maintained for free, so you might not hear back anytime soon, if ever. They may have a paid support or Pro option, which you can find by reading their plugin description or searching the web Also if possible you can try to submit a patch, or a modification to the original plugin, adding in the action or filter you want to be able to use. It’s up to the author of the plugin to include your patch or not and release it for use.
- #18: Go forth and modify plugins using actions and filters