Slides: tollmanz.com/wcsea

There's a Function for That: Doing More for Less With Core Functions

Zack Tollman, 10up LLC
@tollmanz
10up.com
tollmanz.com

Gameplan

Propaganda

Functions

• Function Definition
• Real World Example

Propaganda

Use Core Functions

• Less Overhead
• More Stable
• Easier to Read/Extend/Contribute To

selected

Purpose

Add "selected" attribute to an option tag

Args

• $checked [mixed] value to match against $current
• $current [mixed] value to match against $checked; default = (bool) true
• $echo [bool] true to echo; false to return; default = (bool) true

Return

• [string] 'selected="selected"' or empty string

selected

Example

Aaron Campbell - Twitter Widget Pro

// $instance['items'] = 6
<select name="get_field_name( 'items' ); ?>">
<?php
    for ( $i = 1; $i <= 20; ++$i ) {
        echo "<option value='$i' ";
        selected( $instance['items'], $i );
        echo ">$i</option>";
    }
?>
</select>

<option value='5'>5</option>
<option value='6' selected="selected">6</option>
<option value='7'>7</option>

current_filter

Purpose

Determine the currently running filter within a callback function

Args

• none

Return

• [string] name of the currently executing filter

current_filter

Example

Alex Mills - Localtime

public function add_html( $string, $format ) {
    switch ( current_filter() ) {
        case 'get_the_date':
        case 'get_comment_date':
            $format = get_option( 'date_format' );
            break;

        case 'get_post_time':
        case 'get_comment_time':
            $format = get_option( 'time_format' );
            break;

        default;
            return $string;
    }
}

current_filter

Example

Michael Fields - Taxonomy Images

function taxim_get_terms( $default, $args = array() ) {
    $filter = 'taxim-get-terms';

    if ( $filter !== current_filter() ) {
        taxim_please_use_filter( __FUNCTION__, $filter );
    }
}

human_time_diff

Purpose

Display a human readable time difference

Args

• $from [int] start of interval
• $to [int] end of interval; default = time()

Return

• [string] human readable difference between $from and $to

human_time_diff

Example

Zack Tollman/Helen Hou-Sandí - Debug Bar Cron

$time_next_cron = date( 'Y-m-d H:i:s', $unix_time_next_cron );
$human_time_next_cron = human_time_diff( $unix_time_next_cron );

echo '<h2 class="times"><span>';
echo '__( 'Next Event', 'zt-debug-bar-cron' ) . ':</span>';
echo $time_next_cron . '<br />';
echo $unix_time_next_cron . '<br />';
echo $human_time_next_cron . '</h2>';

add_query_arg

Purpose

Append query variables and values to a URL

Args

• $args [array] query var/value pairs
• $url [string] URL to append query vars to

Return

• [string] URL with query vars appended

add_query_arg

Example

Pippin Williamson - Easy Digital Downloads

function edd_get_download_url( $key, $email, $filekey, $download ) {
    $params = array(
        'download_key' => $key,
        'email' => urlencode( $email ),
        'file' => $filekey,
        'download' => $download,
        'expire' => strtotime( '+1 day', time() )
    );

    $download_url = add_query_arg( $params, home_url() );
    return $download_url;
}

http://site.com/?download_key=key&email=tollmanz@gmail.com...

locate_template

Purpose

Requires a template from either a child or parent theme's folder

Args

• $template_names [array|string] Template file(s) to search for
• $load [bool] True to load template; false to just return path
• $require_once [bool] True for require_once; false for require

Return

• [string] path to file

locate_template

Example

Modern Tribe - The Events Calendar

public static function getTemplateHierarchy( $template ) {
    $tribe_ecp = TribeEvents::instance();

    $templates = array( 'events/' . $template );

    if ( $theme_file = locate_template( $templates ) )
        $file = $theme_file;
    else
        $file = $tribe_ecp->pluginPath . 'views/' . $template;

    return apply_filters( 'tribe_events_template_' . $template, $file );
}

require_if_theme_supports

Purpose

Requires a file if the theme supports a specified feature

Args

• $feature [string] name of theme feature
• $include [string] path to required file

Return

• void

require_if_theme_supports

Example

Justin Tadlock - Theme Hybrid Framework

// In Parent
function extensions() {
    /* Load the Cleaner Caption extension if supported. */
    require_if_theme_supports(
        'cleaner-caption',
        trailingslashit( HYBRID_EXTENSIONS ) . 'cleaner-caption.php'
    );

    /* Load the Entry Views extension if supported. */
    require_if_theme_supports(
        'entry-views',
        trailingslashit( HYBRID_EXTENSIONS ) . 'entry-views.php'
    );
}

// In Child
add_theme_support( 'entry-views' );

get_queried_object_id

Purpose

Gets the ID for the current page's main object

Args

• none

Return

• [integer] ID of the current $wp_the_query object

Related

• get_queried_object

get_queried_object_id

Example

Thorsten Ott - Nav Menu Cache

function hh_cached_nav_menu( $args = array(), $prime = false ) {
    if ( get_queried_object_id() )
        $qoi = get_queried_object_id();
    else
        $qoi = 0;

    $nav_menu_key = md5( serialize( $args ) . '-' . $qoi );

    if ( ! $nav_menu = get_transient( $nav_menu_key ) ) {
        ob_start();
        wp_nav_menu( $args );
        $nav_menu = ob_get_clean();
        set_transient( $nav_menu_key, $nav_menu );
    }

    return $nav_menu;
}

wp_localize_script

Purpose

Writes a JSON encoded object for use with JS

Args

• $handle [string] name of script in which data is used
• $object_name [string] name of resulting JS object
• $l10n [array] array of data

Return

• void

wp_localize_script

Mo Jangda - Zone Manager

function admin_enqueue_scripts() {
    wp_enqueue_script( 'zon-js', URL . 'js/zoninator.js', ... );

    $options = array(
        'baseUrl' => $this->_get_zone_page_url(),
        'adminUrl' => admin_url(),
        ...
        'zoneLockPeriod' => $this->zone_lock_period,
        'zoneLockPeriodMax' => $this->zone_max_lock_period,
    );
    wp_localize_script( 'zon-js', 'zoninatorOptions', $options );
}

wp_localize_script

<script type='text/javascript'>
/* <![CDATA[ */
var zoninatorOptions = {
    "baseUrl":"http:\/\/site.com\/wp-admin\/admin.php?page=zoninator",
    "adminUrl":"http:\/\/site.com\/wp-admin\/",
    "ajaxNonceAction":"zone-nonce-ajax-action",
    "errorGeneral":"Sorry, something went wrong! Please try again?",
    "errorZoneLock":"Sorry, this zone is in use by another user and is currently locked. Please try again later.",
    "errorZoneLockMax":"Sorry, you have reached the maximum idle limit and will now be redirected to the Dashboard.",
    "zoneLockPeriod":"30",
    "zoneLockPeriodMax":"600"
};
/* ]]> */
</script>
<script type='text/javascript'
src='http://site.com/wp-content/plugins/zoninator/js/zoninator.js?ver=0.2'></script>

wp_list_pluck

Purpose

Select a single index's value from a collection of similar objects/arrays

Args

• $list [object|array] A list of objects or arrays
• $field [string|int] A field from $list to obtain

Return

• [array] Single dimension array containing only the $field values from the child array|object within $list

wp_list_pluck

Example

$posts = get_posts();
var_dump( $posts );

wp_list_pluck

Example

array
  0 =>
    object(stdClass)[81]
      public 'ID' => int 801
      public 'post_author' => string '1' (length=1)
      public 'post_date' => string '2012-05-04 17:40:12' (length=19)
        ...
  1 =>
    object(stdClass)[82]
      public 'ID' => int 797
      public 'post_author' => string '2' (length=1)
      public 'post_date' => string '2012-05-04 17:39:30' (length=19)
        ...
  2 =>
    object(stdClass)[83]
      public 'ID' => int 784
      public 'post_author' => string '1' (length=1)
      public 'post_date' => string '2012-04-29 01:22:08' (length=19)
        ...

wp_list_pluck

Example

$posts = get_posts();
$ids = wp_list_pluck( $posts, 'ID' );
var_dump( $ids );

array
  0 => int 801
  1 => int 797
  2 => int 784

wp_list_pluck

Example

Kailey Lampert - Add New Default Avatar

function upgrade() {
    //upgrade option, we can now save multiple avatar options
    $opts = get_option( 'kl_addnewdefaultavatar', false );

    //get current default option
    $current = get_option( 'avatar_default' );

    //get any custom created avatars
    $unavailable = wp_list_pluck( $opts, 'url' );

    //if the current wasn't created by this plugin, update the backup
    if ( ! in_array( $current, $unavailable ) )
        update_option( 'pre_anda_avatar_default', $current );
}

query_posts()

When to Use WP_Query(), query_posts(), and pre_get_posts

Querying Posts Without query_posts()

In Conclusion

Use more Core functions

Read more Core

Me

Zack Tollman

@tollmanz

10up.com

tollmanz.com