Adding Random Posts to Your WordPress Site: 3 Effective Methods

/**
 * Random_Posts widget class
 *
 * Author: haoxian_zeng <http://cnzhx.net/ >
 * Date: 2013.05.14, cnzhx2011 1.0
 */
//--------------- Register the custom widget
class WP_Widget_myRandom_Posts extends WP_Widget {

    function __construct() {
        $widget_ops = array(
            'classname' => 'widget_my_random_posts',
            'description' => __( 'A customized random posts widget for Shuijing Yiye. The cnzhx customized random posts widget.' )
        );
        parent::__construct( 'random-posts', __( 'Random Posts' ), $widget_ops );
        $this->alt_option_name = 'widget_my_random_posts';
    }

    function widget( $args, $instance ) {
        global $randomposts, $post;

        extract( $args, EXTR_SKIP );
        $output = '';
        // Set the widget title
        $title = apply_filters(
            'widget_title',
            empty( $instance['title'] ) ? __( 'Random Posts' ) : $instance['title']
        );

        // Set the number of posts to display
        if ( ! $number = absint( $instance['number'] ) ) {
            $number = 5;
        }

        // WordPress database query: fetch random published posts using the 'rand' orderby parameter
        $randomposts = get_posts( array(
            'number' => $number,
            'orderby' => 'rand',
            'post_status' => 'publish'
        ) );

        // Begin constructing the output markup
        // Output standard widget wrapper opening
        $output .= $before_widget;
        // Output widget title
        if ( $title ) {
            $output .= $before_title . $title . $after_title;
        }

        // Start random posts list
        $output .= '<ul id="randomposts">';
        if ( $randomposts ) {
            foreach ( (array) $randomposts as $post ) {
                $output .= '<li><a href="' . get_permalink() . '">' . esc_html( $post->post_title ) . '</a></li>';
            }
        }
        $output .= '</ul>';
        // Output standard widget wrapper closing
        $output .= $after_widget;

        // Render the final output to the page
        echo $output;
    }

    function update( $new_instance, $old_instance ) {
        $instance = $old_instance;
        $instance['title'] = strip_tags( $new_instance['title'] );
        $instance['number'] = absint( $new_instance['number'] );

        $alloptions = wp_cache_get( 'alloptions', 'options' );
        if ( isset( $alloptions['widget_my_random_posts'] ) ) {
            delete_option( 'widget_my_random_posts' );
        }

        return $instance;
    }

    // Render the widget settings form in the WordPress dashboard
    function form( $instance ) {
        $title = isset( $instance['title'] ) ? esc_attr( $instance['title'] ) : '';
        $number = isset( $instance['number'] ) ? absint( $instance['number'] ) : 5;
        ?>
        <p>
            <label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Title:' ); ?></label>
            <input
                class="widefat"
                id="<?php echo $this->get_field_id( 'title' ); ?>"
                name="<?php echo $this->get_field_name( 'title' ); ?>"
                type="text"
                value="<?php echo $title; ?>"
            />
        </p>

        <p>
            <label for="<?php echo $this->get_field_id( 'number' ); ?>"><?php _e( 'Number of posts to show:' ); ?></label>
            <input
                id="<?php echo $this->get_field_id( 'number' ); ?>"
                name="<?php echo $this->get_field_name( 'number' ); ?>"
                type="number"
                value="<?php echo $number; ?>"
                size="3"
            />
        </p>
        <?php
    }
}

// Register the custom random posts widget
add_action( 'widgets_init', function() {
    return register_widget( 'WP_Widget_myRandom_Posts' );
} );