【 書摘 】Building Web Apps with WordPress – 使用 WordPress API、物件、與實用函式

<?php
/*
  shortcode callback for [msg] shortcode
  Example: [msg type="error"]This is an error message.[/msg]
  Output:
  <div class="message message-error">
      <p>This is an error message.</p>
  </div>
*/
function sp_msg_shortcode($atts, $content)
{
  // 屬性的預設值
  extract( shortcode_atts( array(
        'type' => 'information',
	), $atts ) );
  $content = do_shortcode($content);	//allow nested shortcodes
  $r = '<div class="message message-' .
    $type . '"><p>' . $content . '</p></div>';
  return $r;
}
add_shortcode('msg', 'sp_msg_shortcode');  // msg 為 Shortcode 名稱

<?php
global $post;
$sidebar_content = $post->sidebar_content;
?>
<div class="post">
  <?php the_content(); ?>
</div>
<div class="sidebar">
  <?php
    //echo do_shortcode($sidebar_content);
    echo apply_filters('the_content', $sidebar_content); // 通常用這個
  ?>
</div>

<?php 
// 製作 Shortcode 備份
global $shortcode_tags;
$original_shortcode_tags = $shortcode_tags;

// 移除 Shortcode msg 
unset($shortcode_tags['msg']);

// 輸出內容，這時候 msg 是無法使用的
$content = do_shortcode($content);
echo $content;

// 還原所有 Shortcode
$shortcode_tags = $original_shortcode_tags;

<?php
$atts = shortcode_parse_atts(
  '[soundcloud url="http://api.soundcloud.com/tracks/67658191" params="" width=" 100%" height="166" iframe="true" /]'
);

echo $atts['url']; // 輸出 http://api.soundcloud.com/tracks/67658191

<?php
/*
  Taken from the Widgets API Codex Page at:
  http://codex.wordpress.org/Widgets_API
*/
class My_Widget extends WP_Widget {

	public function __construct() {
		// widget actual processes
	}

	public function widget( $args, $instance ) {
		// outputs the content of the widget
	}

 	public function form( $instance ) {
		// outputs the options form on admin
	}

	public function update( $new_instance, $old_instance ) {
		// processes widget options to be saved
	}
}
add_action( 'widgets_init', function(){
     register_widget( 'My_Widget' );
});

<?php
/*
  Taken from the Widgets API Codex Page at:
  http://codex.wordpress.org/Widgets_API
*/
add_action('widgets_init',
     create_function('', 'return register_widget("My_Widget");')
);

<?php
/*
  Widget to show the current class note.
  Teachers (Group Admins) can change note for each group.
  Shows the global note set in the widget settings if non-empty.
*/
class SchoolPress_Note_Widget extends WP_Widget
{
  public function __construct() {
    parent::__construct(
    'schoolpress_note',
	'SchoolPress Note',
	array( 'description' => 'Note to Show on Group Pages' );
  }

  public function widget( $args, $instance ) {
	global $current_user;

	//saving a note edit?
	if ( !empty( $_POST['schoolpress_note_text'] )
		&& !empty( $_POST['class_id'] ) ) {
	  //make sure this is an admin
	  if(groups_is_user_admin($current_user->ID,intval($_POST['class_id']))){
		//should escape the text and possibly use a nonce
		update_option(
			'schoolpress_note_' . intval( $_POST['class_id'] ),
			$_POST['schoolpress_note_text']
		);
	  }
	}

	//look for a global note
	$note = $instance['note'];

	//get class id for this group
	$class_id = bp_get_current_group_id();

	//look for a class note
	if ( empty( $note ) && !empty( $class_id ) ) {
		$note = get_option( "schoolpress_note_" . $class_id );
	}

	//display note
	if ( !empty( $note ) ) {
		?>
		<div id="schoolpress_note">
			<?php echo wpautop( $note );?>
		</div>
		<?php

		//show edit for group admins
		if ( groups_is_user_admin( $current_user->ID, $class_id ) ) {
		?>
		<a id="schoolpress_note_edit_trigger">Edit</a>
		<div id="schoolpress_note_edit" style="display: none;">
		<form action="" method="post">
		<input type="hidden"
			name="class_id"
			value="<?php echo intval($class_id);?>" />
		<textarea name="schoolpress_note_text" cols="30" rows="5">
		<?php echo esc_textarea(get_option('schoolpress_note_'.$class_id))
		;?>
		</textarea>
		<input type="submit" value="Save" />
		<a id="schoolpress_note_edit_cancel" href="javascript:void(0);">
			Cancel
		</a>
		</form>
		</div>
		<script>
		jQuery(document).ready(function() {
			jQuery('#schoolpress_note_edit_trigger').click(function(){
				jQuery('#schoolpress_note').hide();
				jQuery('#schoolpress_note_edit').show();
			});
			jQuery('#schoolpress_note_edit_cancel').click(function(){
				jQuery('#schoolpress_note').show();
				jQuery('#schoolpress_note_edit').hide();
			});
		});
		</script>
		<?php
		}
	}
  }

  public function form( $instance ) {
	if ( isset( $instance['note'] ) )
		$note = $instance['note'];
	else
		$note = "";
	?>
	<p>
		<label for="<?php echo $this->get_field_id( 'note' ); ?>">
			<?php _e( 'Note:' ); ?>
		</label>
		<textarea id="<?php echo $this->get_field_id( 'note' ); ?>"
			name="<?php echo $this->get_field_name( 'note' ); ?>">
			<?php echo esc_textarea( $note );?>
		</textarea>
	</p>
	<?php
  }

  public function update( $new_instance, $old_instance ) {
	$instance = array();
	$instance['note'] = $new_instance['note'];

	return $instance;
  }
}
add_action( 'widgets_init', function() {
  register_widget( 'SchoolPress_Note_Widget' );
} );

<?php
/**
 * Add a sidebar.
 */
function wpdocs_theme_slug_widgets_init() {
  register_sidebar( array(
    'name'          => __( 'Main Sidebar', 'textdomain' ),    // 區塊名稱，重複名字會+1
    'id'               => 'sidebar-1',                           // 區塊 ID
    'description'   => __( 'Description', 'textdomain' ),     // 區塊說明
    'before_widget' => '<li id="%1$s" class="widget %2$s">',  // 包住區塊的開頭 HTML
    'after_widget'  => '</li>',                               // 包住區塊的結尾 HTML
    'before_title'  => '<h2 class="widgettitle">',            // 包住區塊標題的開頭 HTML
    'after_title'   => '</h2>',                               // 包住區塊標題的結尾 HTML
  ) );
}
add_action( 'widgets_init', 'wpdocs_theme_slug_widgets_init' );

<?php
if(!dynamic_sidebar('schoolpress_student_status'))
{
  //fallback code in case my_widget_area sidebar was not found
}

<?php
//from twenty-thirteen/sidebar.php
if ( is_active_sidebar( 'sidebar-2' ) ) : ?>
	<div id="tertiary" class="sidebar-container" role="complementary">
		<div class="sidebar-inner">
			<div class="widget-area">
				<?php dynamic_sidebar( 'sidebar-2' ); ?>
			</div><!-- .widget-area -->
		</div><!-- .sidebar-inner -->
	</div><!-- #tertiary -->
<?php endif; ?>

<?php
//show note widget, overriding global note
the_widget('SchoolPress_Note_Widget',  //classname
    array('note'=>''), 	               //instance vars
    array(		                       //widget vars
    	'before_widget' => '',
        'after_widget' => '',
        'before_title' => '',
        'after_title' => ''
    )
);

<?php
// Main column (left): 
// 更新瀏覽器通知
$wp_meta_boxes['dashboard']['normal']['high']['dashboard_browser_nag']; 
// 更新 PHP 版本通知
$wp_meta_boxes['dashboard']['normal']['high']['dashboard_php_nag']; 
 
// 網站概況
$wp_meta_boxes['dashboard']['normal']['core']['dashboard_right_now'];
// 多站網站概況
$wp_meta_boxes['dashboard']['normal']['core']['network_dashboard_right_now'];
// 網站活動
$wp_meta_boxes['dashboard']['normal']['core']['dashboard_activity'];
// 網站狀態
$wp_meta_boxes['dashboard']['normal']['core']['health_check_status'];
 
// Side Column (right): 
// WordPress 活動及新聞
$wp_meta_boxes['dashboard']['side']['core']['dashboard_primary'];
// 快速草稿
$wp_meta_boxes['dashboard']['side']['core']['dashboard_quick_press']; 

function wporg_remove_all_dashboard_metaboxes() {
    // Remove Welcome panel
    remove_action( 'welcome_panel', 'wp_welcome_panel' );
    // Remove the rest of the dashboard widgets
    remove_meta_box( 'dashboard_primary', 'dashboard', 'side' );
    remove_meta_box( 'dashboard_quick_press', 'dashboard', 'side' );
    remove_meta_box( 'health_check_status', 'dashboard', 'normal' );
    remove_meta_box( 'dashboard_right_now', 'dashboard', 'normal' );
    remove_meta_box( 'dashboard_activity', 'dashboard', 'normal');
}
add_action( 'wp_dashboard_setup', 'wporg_remove_all_dashboard_metaboxes' );

<?php
//Remove network dashboard widgets
function sp_remove_network_dashboard_widgets()
{
  remove_meta_box('network_dashboard_right_now', 'dashboard-network', 'normal');
  remove_meta_box('dashboard_plugins', 'dashboard-network', 'normal');
  remove_meta_box('dashboard_primary', 'dashboard-network', 'side');
  remove_meta_box('dashboard_secondary', 'dashboard-network', 'side');
}
add_action('wp_network_dashboard_setup', 'sp_remove_network_dashboard_widgets');

<?php
/*
    Add dashboard widgets
*/
function sp_add_dashboard_widgets() {
	wp_add_dashboard_widget(
		'schoolpress_assignments',
		'Assignments',
		'sp_assignments_dashboard_widget',
		'sp_assignments_dashboard_widget_configuration'
	);
}
add_action( 'wp_dashboard_setup', 'sp_add_dashboard_widgets' );

/*
	Assignments dashboard widget
*/
//widget
function sp_assignments_dashboard_widget() {
	$options = get_option( "assignments_dashboard_widget_options", array() );

	if ( !empty( $options['course_id'] ) ) {
		$group = groups_get_group( array(
			'group_id'=>$options['course_id']
			) );
	}

	if ( !empty( $group ) ) {
		echo "Showing assignments for class " .
			$group->name . ".<br />...";
		/*
			get assignments for this group and list their status
		*/
	}
	else {
		echo "Showing all assignments.<br />...";
		/*
			get all assignments and list their status
		*/
	}
}
//configuration
function sp_assignments_dashboard_widget_configuration() {
	//get old settings or default to empty array
	$options = get_option( "assignments_dashboard_widget_options", array() );

	//saving options?
	if ( isset( $_POST['assignments_dashboard_options_save'] ) ) {
		//get course_id
		$options['course_id'] = intval(
			$_POST['assignments_dashboard_course_id']
			);

		//save it
		update_option( "assignments_dashboard_widget_options", $options );
	}

	//show options form
	$groups = groups_get_groups( array( 'orderby'=>'name', 'order'=>'ASC' ) );
	?>
	<p>Choose a class/group to show assignments from.</p>
	<div class="feature_post_class_wrap">
		<label>Class</label>
		<select name="assignments_dashboard_course_id">
		<option value="" <?php selected( $options['course_id'], "" );?>>
			All Classes
		</option>
		<?php
		$groups = groups_get_groups( array( 'orderby'=>'name',
						'order'=>'ASC' ) );

		if ( !empty( $groups ) && !empty( $groups['groups'] ) ) {
			foreach ( $groups['groups'] as $group ) {
			?>
			<option value="<?php echo intval( $group->id );?>"
			<?php selected( $options['course_id'], $group->id );?>>
			<?php echo $group->name;?>
			</option>
			<?php
			}
		}
		?>
		</select>
	</div>
	<input type="hidden" name="assignments_dashboard_options_save" value="1" />
	<?php
}

<?php
global $schoolpress_settings;
$schoolpress_settings = array(
  'info_email' => 'info@schoolpress.me',
  'info_email_name' => 'SchoolPress'
);

<?php
//don't require any caps by default, but allow developers to add checks
$caps = apply_filters('wpdoc_caps', array());

if(!empty($caps))
{
  //guilty until proven innocent
  $hascap = false;

  //must be logged in to have any caps at all
  if(is_user_logged_in())
  {
    //make sure the current user has one of the caps
    foreach($caps as $cap)
    {
      if(current_user_can($cap))
      {
        $hascap = true;
        break;  //stop checking
      }
    }
  }

  if(!$hascap)
  {
    //don't show them the file
    header('HTTP/1.1 503 Service Unavailable', true, 503);
    echo "HTTP/1.1 503 Service Unavailable";
    exit;
  }
}

<?php
 //require any user account
add_filter('wpdoc_caps', function($caps) { return array('read'); });

//require admin account
add_filter('wpdoc_caps', function($caps) { return array('manage_options'); });

//authors only or users with a custom capability (doc)
add_filter('wpdoc_caps', function($caps) { return array('edit_post', 'doc'); });

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

<?php
add_rewrite_rule(
	  '/contact/([^/]+)/?',
	  'index.php?name=contact&subject=' . $matches[1],
	  'top'
	);
add_rewrite_rule(
flush_rewrite_rules();

<?php
//Add rule and flush on activation.
function sp_activation()
{
	add_rewrite_rule(
	  '/contact/([^/]+)/?',
	  'index.php?name=contact&subject=' . $matches[1],
	  'top'
	);
	flush_rewrite_rules();
}
register_activation_hook(__FILE__, 'sp_activation');

/*
  Add rule on init in case another plugin flushes,
  but don't flush cause it's expensive
*/
function sp_init()
{
	add_rewrite_rule(
	  '/contact/([^/]+)/?',
	  'index.php?name=contact&subject=' . $matches[1],
	  'top'
	);
}
add_action('init', 'sp_init');

//Flush rewrite rules on deactivation to remove our rule.
function sp_deactivation()
{
	flush_rewrite_rules();
}
register_deactivation_hook(__FILE__, 'sp_deactivation');

<?php
// 當外掛啟用時建立定時器
function sp_activation()
{
	//do_action('sp_daily_cron'); 定時器名稱叫做 sp_daily_cron
   if ( ! wp_next_scheduled( 'sp_daily_cron' ) ) {
      wp_schedule_event( strtotime( '12:00:00' ), 'daily', 'sp_daily_cron' );
   }
}
register_activation_hook(__FILE__, 'sp_activation');

// 停用外掛時移除定時器
function sp_deactivation()
{
	wp_clear_scheduled_hook('sp_daily_cron');
}
register_deactivation_hook(__FILE__, 'sp_deactivation');

// 要執行的任務
function sp_daily_cron()
{
	//do this daily
}
add_action("sp_daily_cron", "sp_daily_cron");  // 把任務放到定時器裡面

<?php
//add a monthly interval to use in cron jobs
function sp_cron_schedules($schedules)
{
	$schedules['monthly'] = array(
		'interval' => 60*60*24*30, //really 30 days
		'display' => 'Once a Month'
	);
}
add_filter( 'cron_schedules', 'sp_cron_schedules' );

<?php
//run on Mondays
function sp_monday_cron()
{
	//get day of the week, 0-6, starting with Sunday
	$weekday = date("w");

	//is it Monday?
	if($weekday == "1")
	{
		//execute this code on Mondays
	}
}
add_action("sp_daily_cron", "sp_monday_cron");

<?php
 function do_this_in_an_hour() {
 
    // do something
}
add_action( 'my_new_event','do_this_in_an_hour' );
 
// put this line inside a function, 
// presumably in response to something the user does
// otherwise it will schedule a new event on every page visit
 
wp_schedule_single_event( time() + 3600, 'my_new_event' );
 
// time() + 3600 = one hour from now.

disable( "DISABLE_WP_CRON", true );

0 0 * * * wget -O - -q -t 1 https://yoursite.com/wp-cron.php?doing_wp_cron=1

<?php
//run on Mondays
function sp_monday_cron()
{
	//check that cron param was passed in
	if(empty($_REQUEST['sp_cron_monday']))
		return false;

	//execute this code on Mondays
}
add_action("init", "sp_monday_cron");

0 0 * * 1 wget -O  - q -t 1 https://yoursite.com?sp_cron_monday=1

<?php
// 修改寄件人電子郵件與名稱
function sp_wp_mail_from($from_email)
{
  return 'info@schoolpress.me';
}
function sp_wp_mail_from_name($from_name)
{
  return 'SchoolPress';
}
add_filter('wp_mail_from', 'sp_wp_mail_from');
add_filter('wp_mail_from_name', 'sp_wp_mail_from_name');

// 修改電子郵件格式
function sp_wp_mail_content_type( $content_type )
{
  if( $content_type == 'text/plain')
  {
    $content_type = 'text/html';
  }
  return $content_type;
}
add_filter('wp_mail_content_type', 'sp_wp_mail_content_type');

// 自訂頁首與頁尾
function sp_wp_mail_header_footer($email)
{
  //get header
  $headerfile = get_stylesheet_directory() . "email_header.html";
  if(file_exists($headerfile))
    $header = file_get_contents($headerfile);
  else
    $header = "";

  //get footer
  $footerfile = get_stylesheet_directory() . "email_footer.html";
  if(file_exists($footerfile))
    $footer = file_get_contents($footerfile);
  else
    $footer = "";

  //update message
  $email['message'] = $header . $email['message'] . $footer;

  return $email;
}
add_filter('wp_mail', 'sp_wp_mail_header_footer');

/**
 * Plugin Name: Paid Memberships Pro
 * Plugin URI: https://www.paidmembershipspro.com
 * Description: The most complete member management and membership subscriptions plugin for WordPress.
 * Version: 2.3.4
 * Author: Stranger Studios
 * Author URI: https://www.strangerstudios.com
 * Text Domain: paid-memberships-pro
 * Domain Path: /languages
 */

<?php
//must include this file
require_once(ABSPATH . "wp-admin/includes/plugin.php");

//remember current directory
$cwd = getcwd();

//switch to plugin directory
$plugins_dir = ABSPATH . "wp-content/plugins";
chdir($plugins_dir);

echo "<pre>";

//loop through plugin directories and print plugin info
foreach(glob("*", GLOB_ONLYDIR) as $dir)
{
	$plugin = get_plugin_data($plugins_dir .
        "/" . $dir . "/" . $dir . ".php", false, false);
	print_r($plugin);
}

echo "</pre>";

//switch back to current directory just in case
chdir($cwd);

<?php
//remember current directory
$cwd = getcwd();

//switch to themes directory
$themes_dir = dirname(get_template_directory());
chdir($themes_dir);

echo "<pre>";

//loop through theme directories and print theme info
foreach(glob("*", GLOB_ONLYDIR) as $dir)
{
	$theme = wp_get_theme($dir);
	print_r($theme);
}

echo "</pre>";

//switch back to current directory just in case
chdir($cwd);

<?php
//set headers for our files
$default_headers = array(
	"Title" => "Title",
	"Slug" => "Slug",
	"Version" => "Version"
);

//remember current directory
$cwd = getcwd();

//change to reports directory
$reports_dir = dirname(__FILE__) . "/reports";
chdir($reports_dir);

echo "<pre>";

//loop through .php files in reports directory
foreach (glob("*.php") as $filename)
{
	$data = get_file_data($filename, $default_headers, "report");
	print_r($data);
}

echo "</pre>";

//change back to the current directory in case someone expects the default
chdir($cwd);

<?php
/*
Plugin Name: Stop Plugin Updates
Plugin URI: http://bwawwp.com/plugins/stop-plugin-updates/
Description: "Allow Updates: No" i a plugin's header keeps it from updating.
Version: .1
Author: Stranger Studios
Author URI: http://www.strangerstudios.com
*/

//add AllowUpdates header to plugin
function spu_extra_plugin_headers( $headers ) {
    $headers['AllowUpdates'] = "Allow Updates";
	return $headers;
}
add_filter( "extra_plugin_headers", "spu_extra_plugin_headers" );

<?php
/**
* Plugin Name: The Teacher Life Saver
* Plugin URI:  https://schoolpress.me/
* Description: Alert teachers of parent arrivals
* Version:     0.0.1
*/

// 在後台首頁加入家長位置訊息
function ttls_dashboard_widget() {
	global $wp_meta_boxes;

// widget ID, widget name, callback function
wp_add_dashboard_widget('ttls_widget', 'Student Pick Ups', 'ttls_dashboard');
}
add_action('wp_dashboard_setup', 'ttls_dashboard_widget');

// Markup for the dashboard widget
function ttls_dashboard() {
	echo "<div id='ttls_message'></div>";
}

// 修改觸發頻率
function ttls_heartbeat_settings( $settings ) {
    $settings['interval'] = 15; // Anything between 15-60 seconds
    return $settings;
}
add_filter( 'heartbeat_settings', 'ttls_heartbeat_settings', 1 );

// Enqueue heartbeat.js and our JavaScript functions
function ttls_heartbeat_init()
{
	  // Only run this on the dashboard page (index.php)
	  global $pagenow;
	  if( $pagenow != 'index.php' )
		  return;

  // Enqueue the Heartbeat API
  wp_enqueue_script('heartbeat');

  // Load our JavaScript functions in the footer
  add_action("admin_footer", "ttls_js_wp_footer");
}
add_action("admin_init", "ttls_heartbeat_init");

// JavaScript functions ran in the footer
function ttls_js_wp_footer()
{
?>
<script>
jQuery(document).ready(function() {

// 送資料給 server
	jQuery(document).on('heartbeat-send', function(e, data) {
		data['client'] = 'check-for-parents';
});

// 接收從 server 回傳的資料
jQuery(document).on('heartbeat-tick', function(e, data) {
if(data['server'])
	document.getElementById("ttls_message").innerHTML = data['server'] 
	+ document.getElementById("ttls_message").innerHTML;
	});
});
</script>
<?php
}

// 處理從 hearbeat-send 接收到的資料然後傳給 hearbeat-tick
function ttls_heartbeat_received($response, $data)
{
// Look for whatever data was passed from JS heartbeat-send function
if($data['client'] == 'check-for-parents')
{
  // Build whatever response you want
  $r = '<p>';
  $r .= date( 'm/j/y g:i a', current_time( 'timestamp', 0 ) );
  $r .= " - Nina Messenlehner's father Brian Messenlehner ";
  $r .= "has arrived in a 2007 White Hummer H2.";
  $r .= '</p>';

  return $r;
}
add_filter('heartbeat_received', 'ttls_heartbeat_received', 10, 2);