WordpressのSeriesプラグインのウィジェットをサムネイル画像が出力される様にカスタマイズした物

custom-series-list-related.php

<?php

class Custom_List_Related extends \WP_Widget {

    /**
     * Default arguments for the widget settings.
     *
     * @since  2.0.0
     * @access public
     * @var    array
     */
    public $defaults = array();

    /**
     * Set up the widget's unique name, ID, class, description, and other options.
     *
     * @since  2.0.0
     * @access public
     * @return void
     */
    public function __construct() {

        // Set up the widget options.
        $widget_options = array(
            'classname'   => 'custom-series-list-related',
            'description' => esc_html__( "Displays a list of posts within the current post's series.", 'series' )
        );

        // Create the widget.
        parent::__construct( 'custom-series-list-related', __( 'Series - Custom List Related', 'series' ), $widget_options );

        // Set up defaults.
        $this->defaults = array(
            'title'          => __( 'In Series', 'series' ),
            'order'          => 'ASC',
            'orderby'        => 'date',
            'posts_per_page' => -1
        );
    }

    /**
     * Outputs the widget based on the arguments input through the widget controls.
     *
     * @since  2.0.0
     * @access public
     * @return void
     */
    public function widget( $sidebar, $instance ) {

        if ( ! is_singular() )
            return;

        // Set the $args for wp_get_archives() to the $instance array.
        $args = wp_parse_args( $instance, $this->defaults );

        // Don't echo.
        $args['echo'] = false;

        // Get the series list.
        $list = $this->list_related_posts( get_queried_object_id(), $args );

        // Only display if we have a series.
        if ( empty( $list ) )
            return;

        // Output the theme's widget wrapper.
        echo $sidebar['before_widget'];

        // If a title was input by the user, display it.
        if ( ! empty( $instance['title'] ) )
            echo $sidebar['before_title'] . apply_filters( 'widget_title', $instance['title'], $instance, $this->id_base ) . $sidebar['after_title'];

        // Output the list.
        echo $list;

        // Close the theme's widget wrapper.
        echo $sidebar['after_widget'];
    }

    /**
     * Displays the widget control options in the Widgets admin screen.
     *
     * @since  2.0.0
     * @access public
     * @param  array  $instance
     * @param  void
     */
    public function form( $instance ) {

        // Merge the user-selected arguments with the defaults.
        $instance = wp_parse_args( (array) $instance, $this->defaults );

        // Orderby options.
        $orderby = array(
            'ID'            => __( 'ID',               'series' ),
            'author'        => __( 'Author',           'series' ),
            'none'          => __( 'None',             'series' ),
            'title'         => __( 'Title',            'series' ),
            'name'          => __( 'Slug',             'series' ),
            'date'          => __( 'Date (Published)', 'series' ),
            'modified'      => __( 'Date (Modified)',  'series' ),
            'random'        => __( 'Random',           'series' ),
            'comment_count' => __( 'Comment Count',    'series' )
        );

        // Order options.
        $order = array(
            'ASC'  => __( 'Ascending',  'series' ),
            'DESC' => __( 'Descending', 'series' )
        ); ?>

        <p>
            <label>
                <?php esc_html_e( 'Title:', 'series' ); ?>
                <input type="text" class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo esc_attr( $this->get_field_name( 'title' ) ); ?>" value="<?php echo esc_attr( $instance['title'] ); ?>" />
            </label>
        </p>

        <p>
            <label>
                <?php esc_html_e( 'Order By:', 'series' ); ?>

                <select class="widefat" name="<?php echo esc_attr( $this->get_field_name( 'orderby' ) ); ?>">
                    <?php foreach ( $orderby as $option_value => $option_label ) : ?>
                        <option value="<?php echo esc_attr( $option_value ); ?>" <?php selected( $instance['orderby'], $option_value ); ?>><?php echo esc_html( $option_label ); ?></option>
                    <?php endforeach; ?>
                </select>
            </label>
        </p>

        <p>
            <label>
                <?php esc_html_e( 'Order:', 'series' ); ?>

                <select class="widefat" name="<?php echo esc_attr( $this->get_field_name( 'order' ) ); ?>">
                    <?php foreach ( $order as $option_value => $option_label ) : ?>
                        <option value="<?php echo esc_attr( $option_value ); ?>" <?php selected( $instance['order'], $option_value ); ?>><?php echo esc_html( $option_label ); ?></option>
                    <?php endforeach; ?>
                </select>
            </label>
        </p>

        <p>
            <label>
                <?php esc_html_e( 'Limit:', 'series' ); ?>
                <input type="text" class="widefat" name="<?php echo esc_attr( $this->get_field_name( 'posts_per_page' ) ); ?>" value="<?php echo esc_attr( $instance['posts_per_page'] ); ?>" />
            </label>
        </p>
    <?php
    }

    /**
     * Displays a list of posts by series.
     *
     * @since  2.0.0
     * @param  array   $args
     * @return string
     */
    function list_posts( $args = array() ) {

        if ( empty( $args['series'] ) )
            return;

        $out     = '';
        $post_id = 0;

        if ( in_the_loop() )
            $post_id = get_the_ID();

        else if ( is_singular() )
            $post_id = get_queried_object_id();

        $defaults = array(
            'series'         => '', // term slug
            'order'          => 'ASC',
            'orderby'        => 'date',
            'posts_per_page' => -1,
            'echo'           => true
        );

        $args = wp_parse_args( $args, $defaults );

        $query_args = array(
            'order'          => $args['order'],
            'orderby'        => $args['orderby'],
            'posts_per_page' => $args['posts_per_page'],
            'tax_query'      => array(
                array(
                    'taxonomy' => \Series\get_series_taxonomy(),
                    'field'    => is_numeric( $args['series'] ) ? 'term_id' : 'slug',
                    'terms'    => array( $args['series'] )
                )
            )
        );

        $loop = new \WP_Query( $query_args );

        if ( $loop->have_posts() ) {

            $out .= '<ul class="series-list">';

            while ( $loop->have_posts() ) {

                $loop->the_post();

                $thumbnail = "";
                if ( has_post_thumbnail() ) {
                    $thumbnail = '<div>' . get_the_post_thumbnail() . '</div>';
                }

                $title = get_the_title() ? the_title( '', '', false ) : get_the_ID();

                $out .= $post_id === get_the_ID()
                    ? sprintf( '<li>%s%s</li>', $thumbnail, $title )
                    : sprintf( '<li><a href="%s">%s%s</a></li>', esc_url( get_permalink() ), $thumbnail, $title );
            }

            $out .= '</ul>';
        }

        wp_reset_postdata();

        if ( false === $args['echo'] )
            return $out;

        echo $out;
    }

    /**
     * Displays a list of posts related to the current post.
     *
     * @since  2.0.0
     * @param  int     $post_id
     * @param  array   $args
     * @return string
     */
    function list_related_posts( $post_id = 0, $args = array() ) {

        if ( ! $post_id )
            get_the_ID();

        if ( $post_id )
            $series = get_the_terms( $post_id, \Series\get_series_taxonomy() );

        if ( empty( $series ) )
            return;

        $series = reset( $series );

        $args['series'] = $series->slug;

        return $this->list_posts( $args );
    }
}