Extensible WordPress Plugins

Some hints and tips about how to make your plugins and themes more extensible to other developers so they can build on them or modify them safely.

Transcript

1. markwilkinson.me | @wpmark
   Extensible WordPress
   Plugins
   WordPress Cumbria – 14th October 2014
   #wpcumbria
   

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2. mark wilkinson?
   

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3. markwilkinson.me | @wpmark
   father
   

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4. markwilkinson.me | @wpmark
   teacher
   

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5. markwilkinson.me | @wpmark
   WordPress developer
   

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6. markwilkinson.me | @wpmark
   

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7. markwilkinson.me | @wpmark
   this talk will cover
   what is extensibility?
   why should you be making extensible plugins?
   how to make your plugin extensible?
   examples of good practice
   

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8. markwilkinson.me | @wpmark
   this talk will cover
   what is extensibility?
   why should you be making extensible plugins?
   how to make your plugin extensible?
   examples of good practice
   

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9. markwilkinson.me | @wpmark
   this talk will cover
   what is extensibility?
   why should you be making extensible plugins?
   how to make your plugin extensible?
   examples of good practice
   

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10. markwilkinson.me | @wpmark
    this talk will cover
    what is extensibility?
    why should you be making extensible plugins?
    how to make your plugin extensible?
    examples of good practice
    

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11. markwilkinson.me | @wpmark
    Plugin and / or Theme
    

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12. markwilkinson.me | @wpmark
    Extensible Plugins
    

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13. markwilkinson.me | @wpmark
    “one that can be
    modified or extended
    without changing the
    plugin code itself ”
    

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14. markwilkinson.me | @wpmark
    why?
    

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15. markwilkinson.me | @wpmark
    https://www.flickr.com/photos/damndirty/10166197684
    

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16. markwilkinson.me | @wpmark
    preserve future
    updatability
    

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17. markwilkinson.me | @wpmark
    how?
    

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18. markwilkinson.me | @wpmark
    actions & filters
    

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19. markwilkinson.me | @wpmark
    do_action()
    

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20. markwilkinson.me | @wpmark
    do_action(
    $tag,
    $args
    );
    

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21. markwilkinson.me | @wpmark
    add_action()
    

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22. markwilkinson.me | @wpmark
    add_action(
    $hook,
    $function,
    $priority,
    $accepted_args
    );
    

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23. markwilkinson.me | @wpmark
    example
    

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24. markwilkinson.me | @wpmark
    $q = new WP_Query( $q_args );
    while( $q->have_posts() ) : $->the_post();
    ?>
    
    endwhile;
    

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25. markwilkinson.me | @wpmark
    $q = new WP_Query( $q_args );
    while( $q->have_posts() ) : $->the_post();
    do_action( ‘wpmark_before_post’, get_the_ID() );
    ?>
    
    endwhile;
    

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26. markwilkinson.me | @wpmark
    $q = new WP_Query( $q_args );
    while( $q->have_posts() ) : $->the_post();
    do_action( ‘wpmark_before_post’, get_the_ID() );
    ?>
    
    do_action( ‘wpmark_after_post’, get_the_ID() );
    endwhile;
    

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27. markwilkinson.me | @wpmark
    function wpmark_add_before_post( $post_id ) {
    $meta = get_post_meta( $post_id, ‘key’, true );
    /* do something with $meta */
    }
    add_action(
    ‘wpmark_before_post’,
    ‘wpmark_add_before_post’,
    10,
    1
    );
    

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28. markwilkinson.me | @wpmark
    apply_filters()
    

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29. markwilkinson.me | @wpmark
    apply_filters(
    $tag,
    $value,
    $var
    );
    

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30. markwilkinson.me | @wpmark
    add_filter()
    

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31. markwilkinson.me | @wpmark
    add_filter(
    $hook,
    $function,
    $priority,
    $accepted_args
    );
    

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32. markwilkinson.me | @wpmark
    example
    

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33. markwilkinson.me | @wpmark
    $q_args = array(
    'post_type' => ’post',
    'cat' => 1
    );
    

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34. markwilkinson.me | @wpmark
    $q_args = apply_filters(
    ‘wpmark_q_args’,
    array(
    ‘post_type’ => ‘post’,
    ‘cat’ => 1
    )
    );
    

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35. markwilkinson.me | @wpmark
    function wpmark_edit_q_args( $args ) {
    $args[ ‘year’ ] = ‘2014’;
    return $args;
    }
    add_filter(
    ‘wpmark_q_args’,
    ‘wpmark_edit_q_args’
    10,
    1
    );
    

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36. markwilkinson.me | @wpmark
    conclusion
    

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37. markwilkinson.me | @wpmark
    when making plugins &
    themes, remember to…
    

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38. markwilkinson.me | @wpmark
    do_action()
    &
    apply_filters()
    

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39. markwilkinson.me | @wpmark
    Thank you!
    Questions: @wpmark (or now!)
    Slides: markwilkinson.me (soon!)
    

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