LiveWhale Calendar Widget

livewhale-calendar-widget.php

<?php
/*
Plugin Name: LiveWhale Calendar Widget (TAMU)
Description: WordPress widget to display events from a LiveWhale calendar feed.
Author: Stephanie Leary
Version: 1.0
Author URI: http://stephanieleary.com
*/

// initialize all custom widgets
function scl_widgets_init() {
	register_widget( 'SCL_LiveWhale_Calendar_Widget' );
}

add_action( 'widgets_init', 'scl_widgets_init', 99 );

class SCL_LiveWhale_Calendar_Widget extends WP_Widget {

	public function __construct() {
		$widget_ops = array( 'description' => esc_html__( 'Add a calendar from LiveWhale.', 'tees' ) );
		parent::__construct( 'livewhale_calendar', esc_html__( 'Calendar (LiveWhale)', 'tees'), $widget_ops );
	}


	public function widget( $args, $instance ) {
		
		if ( empty( $instance['calendar_id'] ) )
			return;
		
		/** This filter is documented in wp-includes/widgets/class-wp-widget-pages.php */
		$instance['title'] = apply_filters( 'widget_title', empty( $instance['title'] ) ? '' : $instance['title'], $instance, $this->id_base );

		echo $args['before_widget'];

		if ( !empty( $instance['title'] ) )
			echo $args['before_title'] . $instance['title'] . $args['after_title'];

		$extra_args = '';
		$transient_name = 'lwc2'; // LWCal + widget ID, will add options to this name below. "lwc" for "LiveWhale Calendar" because the max length on these is 64 characters.
		$find = array( ' ',',','&' );
		$replace = array( '_','','_' );
		if ( !empty( $instance['groups'] ) ) {
			$extra_args .= '/group/' . rawurlencode( trim( $instance['groups'] ) );
			$transient_name .= '_group_'.str_replace( $find, $replace, strtolower( trim( $instance['groups'] ) ));
		} 
		else {
			$transient_name .= '_allgroups';
		}
		if ( $instance['max_events'] ) {
			$extra_args .= '/max/' . trim( $instance['max_events'] );
			$transient_name .= '_max' . trim( $instance['max_events'] );
		}
		if ( $instance['tags'] ) {
			$events_tags = explode( ',', $instance['tags'] );
			$transient_name .= '_tags';
			foreach( $events_tags as $tag ){
				$extra_args .= '/tag/' . rawurlencode( trim( $tag ) );
				$transient_name .= '_' . str_replace( $find, $replace, trim( $tag ) );
			}
		}
		$transient_name = substr( $transient_name, 0, 64 ); // transient names limited to 64 characters, so let's not go over.
		// Check the transient, and if it's expired/empty, refresh it:
		$events_transient = get_transient( $transient_name );
		if ( empty( $events_transient ) ) {
			$url = 'http://calendar.tamu.edu/live/widget/' . $instance['calendar_id'] . $extra_args . '?external_widget=1';
			$response = wp_remote_retrieve_body( wp_remote_get( $url ) );
			if ( !is_wp_error( $response ) ) {
				echo wp_kses( $response );
				set_transient( $transient_name, $response, HOUR_IN_SECONDS );
			}
		} 
		else {
			echo wp_kses( $events_transient );
		}

		echo $args['after_widget'];
	}


	public function update( $new_instance, $old_instance ) {
		$instance = array();
		if ( ! empty( $new_instance['calendar_id'] ) ) {
			$instance['calendar_id'] = absint( $new_instance['calendar_id'] );
		}
		if ( ! empty( $new_instance['title'] ) ) {
			$instance['title'] = sanitize_text_field( stripslashes( $new_instance['title'] ) );
		}
		if ( ! empty( $new_instance['groups'] ) ) {
			$instance['groups'] = sanitize_text_field( stripslashes( $new_instance['groups'] ) );
		}
		if ( ! empty( $new_instance['tags'] ) ) {
			$instance['tags'] = sanitize_text_field( stripslashes( $new_instance['tags'] ) );
		}
		$instance['max_events'] = absint( $new_instance['max_events'] );
		return $instance;
	}


	public function form( $instance ) {
		$id = isset( $instance['calendar_id'] ) ? $instance['calendar_id'] : '';
		$title = isset( $instance['title'] ) ? $instance['title'] : '';
		$tags = isset( $instance['tags'] ) ? $instance['tags'] : '';
		$groups = isset( $instance['groups'] ) ? $instance['groups'] : '';
		$max = isset( $instance['max_events'] ) ? $instance['max_events'] : '';
		?>

			<p>
				<label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php esc_html_e( 'Title:', 'tees' ) ?></label>
				<input type="text" class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" value="<?php echo esc_attr( $title ); ?>"/>
			</p>
			<p>
				<label for="<?php echo $this->get_field_id( 'calendar_id' ); ?>"><?php esc_html_e( 'Calendar ID:', 'tees' ) ?></label>
				<input type="text" class="widefat" id="<?php echo $this->get_field_id( 'calendar_id' ); ?>" name="<?php echo $this->get_field_name( 'calendar_id' ); ?>" value="<?php echo esc_attr( $id ); ?>"/>
			</p>
			<p>
				<label for="<?php echo $this->get_field_id( 'groups' ); ?>"><?php esc_html_e( 'Groups:', 'tees' ) ?></label>
				<input type="text" class="widefat" id="<?php echo $this->get_field_id( 'groups' ); ?>" name="<?php echo $this->get_field_name( 'groups' ); ?>" value="<?php echo esc_attr( $groups ); ?>"/>
			</p>
			<p>
				<label for="<?php echo $this->get_field_id( 'tags' ); ?>"><?php esc_html_e( 'Tags:', 'tees' ) ?></label>
				<input type="text" class="widefat" id="<?php echo $this->get_field_id( 'tags' ); ?>" name="<?php echo $this->get_field_name( 'tags' ); ?>" value="<?php echo esc_attr( $tags ); ?>"/>
			</p>
			<p>
				<label for="<?php echo $this->get_field_id( 'max_events' ); ?>"><?php esc_html_e( 'Number of Events to Display:', 'tees' ) ?></label>
				<input type="text" class="widefat" id="<?php echo $this->get_field_id( 'max_events' ); ?>" name="<?php echo $this->get_field_name( 'max_events' ); ?>" value="<?php echo esc_attr( $max ); ?>"/>
			</p>
		<?php
	}
}