The Fundamentals of Creating Sound Plugins

Thanks to WordPress core making plugins to add functionality is not that difficult. However for each plugin you make, there are some sound principles you should follow in order to make your plugin the best it can be.

This talk will teach you some of the principles to follow when making your plugins, which will make it easier for you to develop and upgrade your plugin, as well as allowing other developers to make changes in a safer way and keep things secure. Ideal for beginners and intermediate developers in plugin development.

Transcript

1. https://highrise.digital
   @wpmark
   The Fundamentals of
   Creating Sound Plugins
   Mark Wilkinson

   WordCamp Manchester 2017
   

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   @wpmark
   #1 Security
   

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   sanitize_*()
   sanitize_text_field() / sanitize_email()
   sanitize_option() / sanitize_title_with_dashes()
   sanitize_option()
   …
   

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   esc_*()
   esc_url() / esc_html()
   esc_attr() / esc_textarea()
   esc_js()
   …
   

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   Others
   wp_kses_post()
   absint() / intval()
   wp_redirect() / wp_safe_redirect()
   $wpdb->* / is_email()
   array_map( 'absint', $array )
   …
   

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   $title = sanitize_text_field( $_POST['title'] );
   update_post_meta( $post_id, 'title', $title );
   

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   $title = sanitize_text_field( $_POST['title'] );
   update_post_meta( $post_id, 'title', $title );
   $title = get_post_meta( $post_id, 'title', true );
   echo esc_html( $title );
   

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   #2
   Reliability / Scalability
   

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    Watch out for
    notices & warnings
    'WP_DEBUG' = true
    

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    Efficient Queries
    posts_per_page = -1
    

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    Efficient Queries
    posts_per_page = -1
    posts_per_page = 100
    

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    Efficient Queries
    posts_per_page = -1
    posts_per_page = 100
    meta_query = array( … )
    

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15. https://highrise.digital
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    Efficient Queries
    posts_per_page = -1
    posts_per_page = 100
    meta_query = array( … )
    tax_query = array( … )
    

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16. https://highrise.digital
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    Efficient Queries
    posts_per_page = -1
    posts_per_page = 100
    meta_query = array( … )
    tax_query = array( … )
    https://10up.github.io/Engineering-Best-Practices/php/
    

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    Complex Queries
    Cache ‘em
    get_transient()
    set_transient()
    wp_cache_set()
    wp_cache_get()
    

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    Don’t re-invent
    the wheel!
    Use WordPress functions
    

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    #3 Maintainability
    

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    Activation / De-activation
    register_activation_hook(
    __FILE__,
    ‘hd_function_to_run’
    );
    

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    Activation / De-activation
    register_deactivation_hook(
    __FILE__,
    ‘hd_function_to_run’
    );
    

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    uninstall.php
    Runs when a user deletes the plugin
    Clean up options, removing DB tables
    https://developer.wordpress.org/plugins/the-basics/uninstall-methods/
    

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    Use functions / methods
    get_option( 'hd_version' );
    

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    Use functions / methods
    get_option( 'hd_version' );
    hd_get_version();
    

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    #4 Compatibility
    

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    prefix_all
    get_version();
    

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    prefix_all
    get_version();
    hd_get_version();
    

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    Enqueue Scripts / Styles
    wp_enqueue_script();
    wp_enqueue_style();
    

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    #5 Extensibility
    https://wordpress.tv/2014/08/29/mark-wilkinson-easy-extensible-plugins/
    

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    Template Overrides
    if ( file_exists( STYLESHEETPATH . '/file.php' ) {
    // load template from theme.
    } else {
    // load template from plugin.
    }
    

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    Function Overrides
    if ( ! function_exists( 'hd_function' ) {
    function hd_function() {
    // some function stuff!
    }
    }
    

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    Actions & Filters
    do_action();
    apply_filters();
    

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    #6 Usability
    

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36. https://highrise.digital
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    Mark Wilkinson
    WordPress Developer & Co-founder @ Highrise Digital
    https://highrise.digital
    @wpmark
    

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