Understanding WordPress Filters and Actions

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W O R D P R E S S F I LT E R S & A C T I O N S

U N D E R S TA N D I N G

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H I .

Designer, developer, marketer, shit-talker, etc.

Owner build/create studios

@buildcreate @wilsonographybuildcreate.com

I ’ M I A N , N I C E T O M E E T Y O U .

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M Y S E L F I S H G O A L S F O R Y O U

I want you to walk away from this feeling a little less hacky, a little more informed, and most of all inspired.

I want you to have an “Ah ha!” moment, where suddenly your understanding of WordPress becomes that much clearer, and you can’t wait to get out of this room to try out your new knowledge.

Here goes nothing…

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A W O R L D W I T H O U T H O O K S

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I T ’ S P R E T T Y D A M N H A C K Y

• Including extra PHP files for ajax requests

• Hacking into plugins to change display/functionality

• Hacking *gasp* WP core files

• Hacking theme files (when you should be using a child theme)

• Hackity hack hack hack.

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L E T ’ S TA L K A B O U T H O O K S

“Hooks enable us to literally hook into parts of the WordPress page lifecycle to retrieve, insert, or modify data, or they allow us to take certain actions behind the scenes.”

- T O M M C FA R L I N @ T U T S P L U S

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Where does all of this fit into the WP loading process?

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S O T H E Y ’ R E B O T H H O O K S , T H E Y C A N K E E P M E F R O M H A C K I N G M Y W O R D P R E S S I N S TA L L T O S H R E D S W I T H M Y I N E P T I T U D E , I G E T T H AT, W H AT ’ S T H E D I F F E R E N C E ?

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F I LT E R S

• Applying changes to content/data

• Uses functions:

• apply_filters()

• add_filters()

A C T I O N S

• Hooks your functions into an action in WP

• Uses functions:

• do_action()

• add_action()

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F I LT E R S

• Change something you’re pulling out of WP

• Change something you’re putting into the WP database

A C T I O N S

• Using WP Ajax

• Tying into existing WP processes, like sending email

• Adding styles or js to the page

W H E N S H O U L D W E U S E T H E S E L O V E LY H O O K S ?

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A K A A L L T H E D A M N T I M E . I T ’ S F R E A K I N G M A G I C P E O P L E .

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S O , L E T S M A K E S O M E M A G I C …

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I N Y O U R T E M P L A T E F I L E

I N Y O U R F U N C T I O N S F I L E

L E T S M A K E A N A C T I O N !

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I N Y O U R F U N C T I O N S F I L E

L E T S F I LT E R T H E C O N T E N T !

( Y E A H I T ’ S T H AT S I M P L E , A N D T H I S I S L I K E 9 0 % O F W H AT I U S E F I LT E R S F O R )

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L E T S G E T D A N G E R O U S

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A D D I N G D A N C I N G O L D P E O P L E T O T H E PA G E I S F U N , B U T H O W A B O U T S O M E T H I N G Y O U C A N A C T U A L LY U S E …

Adding our JS to the footer with the wp_footer hook

Tying into the WP Ajax hooks and creating our callback

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L E T S M A K E O U R O W N F I LT E R , S T Y L E A N A R R AY, T H E N A P P LY A N O T H E R F I LT E R T O T H AT F I LT E R , T H E N S P I T I T A L L O U T O N T H E PA G E …

Filters, not just for strings any more. Let’s format the hell out of this array!

Take note of the priority difference between the filters!

Now in our page template we can feed some content into the filter and get the result back.

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W A N T T O A D D A S E A R C H F O R M T O Y O U R M A I N N AV ? T H E R E ’ S A H O O K F O R T H AT.

We get the menu HTML from WordPress, and simply append our search form and return the result.

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M E O W W E ’ R E TA L K I N !

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N O W Y O U ’ R E T H I N K I N G W I T H H O O K S

• Magical WP-friendly ajax requests!

• Work WITH plugins as the author intended instead of hacking them!

• GTFO WP core files!

• Build better themes and child themes!

• ????

• Profit!

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T H A N K S F O R C O M I N G !

• http://codex.wordpress.org/Plugin_API/Action_Reference

• http://code.tutsplus.com/articles/the-beginners-guide-to-wordpress-actions-and-filters--wp-27373

• http://www.zell-weekeat.com/wordpress-actions-and-filters/

• http://codex.wordpress.org/Plugin_API/Filter_Reference

R E S O U R C E S

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