Passing search query and custom filter to wp_list_table grid

Question

I'm using extended WP_List_Table class to output my custom DB data. Facing with a problem - if I search or filter my data, everything works fine, but if I go to the next page or click any sorted header, my data will reset. This happened, because paging and sorting not included search string or filter params ($_REQUEST['s']) and I don't understand, how to include it. If I switch my global table <form> method from POST to GET, it will solve the problem, but because action is empty, whole query string including to action and after 3-4 iteration I will get 414 error (uri too large).

<?php

if ( !class_exists( 'WP_List_Table' ) ) {
    require_once( ABSPATH . 'wp-admin/includes/class-wp-list-table.php' );
}

class BWCU_List_Table extends WP_List_Table {

    private $_user_fields_mapping = [];

    function __construct( $user_fields_mapping ) {

        $this->_user_fields_mapping = $user_fields_mapping;

        parent::__construct(
            [
                'singular' => 'blacklist',
                'plural'   => 'blacklists',
                'ajax'     => false,
            ]
        );

        add_screen_option(
            'per_page',
            [
                'label'   => __( 'Items per page', 'textdomain' ),
                'default' => 10,
                'option'  => 'per_page',
            ]
        );

    }

    function get_columns() {
        $columns = [
            'cb'        => '<input type="checkbox" />', //Render a checkbox instead of text
            'value'     => __('Name', 'textdomain'),
            'type'      => __('Type', 'textdomain'),
            'reason'    => __('Reason', 'textdomain'),
            'user_id'   => __('User', 'textdomain'),
            'order_id'  => __('Order', 'textdomain'),
            'date'      => __('Date', 'textdomain'),
        ];

        return $columns;
    }

    function column_default( $item, $column_name ) {
        return $item[ $column_name ];
    }

    function column_cb( $item ) {
        return sprintf(
            '<input type="checkbox" name="id[]" value="%s" />',
            $item['ID']
        );
    }

    function column_value( $item ) {
        return $item['value'];
    }

    function column_type( $item ) {
        return $this->_user_fields_mapping[ $item['type'] ]['name'];
    }

    function column_reason( $item ) {
        return $item['reason'];
    }

    function column_user( $item ) {
        $user_data = get_userdata( $item['user_id'] );
        return !empty( $item['user_id'] ) ? sprintf('<a href="%s" target="_blank">%s</a>', get_edit_user_link( $item['user_id'] ), $user_data->user_login ) : '&mdash;';
    }

    function column_order( $item ) {
        return !empty( $item['order_id'] ) ? sprintf('<a href="/wp-admin/post.php?post=%d&action=edit" target="_blank">%s%d</a>', $item['order_id'] , __('Order ', 'textdomain' ), $item['order_id'] ) : '&mdash;';
    }

    function column_date( $item ) {
        return $item['created_at'];
    }

    function process_bulk_action() {
        global $wpdb;

        if ( 'delete' === $this->current_action() ) {
            $ids = isset( $_REQUEST['id'] ) ? $_REQUEST['id'] : [];

            if ( !empty( $ids ) ) {
                $placeholders = array_fill(0, count( $ids ), '%d');
                $wpdb->query(
                    $wpdb->prepare(
                        'DELETE FROM ' . $wpdb->prefix . 'bl_data WHERE id IN(' . implode(', ', $placeholders ) . ')',
                        $ids
                    )
                );
            }
        }
    }

    function prepare_items() {
        global $wpdb;

        $per_page = get_user_meta( get_current_user_id(), get_current_screen()->get_option( 'per_page', 'option' ), true ) ? : 10;
        $columns = $this->get_columns();
        $hidden = [];
        $sortable = $this->get_sortable_columns();

        // here we configure table headers, defined in our methods
        $this->_column_headers = [ $columns, $hidden, $sortable ];

        // [OPTIONAL] process bulk action if any
        $this->process_bulk_action();

        // prepare query params, as usual current page, order by and order direction
        $paged = isset($_REQUEST['paged']) ? max(0, intval($_REQUEST['paged'] - 1) * $per_page) : 0;
        $orderby = (isset($_REQUEST['orderby']) && in_array($_REQUEST['orderby'], array_keys($this->get_sortable_columns()))) ? $_REQUEST['orderby'] : 'value';
        $order = (isset($_REQUEST['order']) && in_array($_REQUEST['order'], array('asc', 'desc'))) ? $_REQUEST['order'] : 'asc';

        $where = $args = [];
        if ( isset( $_REQUEST['s'] ) && !empty( $_REQUEST['s'] ) ) {
            $where[] =  'value LIKE "%%%s%%"';
            $args[] =  $_REQUEST['s'];
        }

        if ( isset( $_REQUEST['filter-type'] ) && !empty( $_REQUEST['filter-type'] ) && ( $_REQUEST['filter-type'] != '0' ) ) {
            $where[] = 'type="%s"';
            $args[] = $_REQUEST['filter-type'];
        }

        $where = !empty( $where ) ? ' WHERE ' . implode(' AND ', $where) : '';
        $total_query = 'SELECT COUNT(*) FROM ' . $wpdb->prefix . 'bl_data' . $where;
        $total_items = $wpdb->get_var( $wpdb->prepare( $total_query, $args ) );

        array_push( $args, $per_page, $paged );

        $query = 'SELECT ID, value, type, reason, order_id, user_id, created_at FROM ' . $wpdb->prefix . 'bl_data' . $where . ' ORDER BY ' . $orderby . ' ' . $order . ' LIMIT %d OFFSET %d';

        $this->items = $wpdb->get_results(
            $wpdb->prepare( $query, $args ),
            ARRAY_A
        );

        $this->set_pagination_args(
            [
                'total_items' => $total_items,
                'per_page' => $per_page,
                'total_pages' => ceil( $total_items / $per_page )
            ]
        );
    }

    function no_items() {
        _e( 'No records found.', 'textdomain' );
    }

    function get_sortable_columns() {
        $sortable_columns = [
            'value' => ['value', true],
            'type' => ['type', false],
            'user_id' => ['user_id', false],
            'order_id' => ['order_id', false],
            'date' => ['date', false],
        ];
        return $sortable_columns;
    }

    function get_bulk_actions() {
        $actions = [
            'delete' => __('Delete', 'textdomain')
        ];
        return $actions;
    }

    function extra_tablenav( $which ) {
        if ( $which == "top" ){
            ?>
            <div class="alignleft actions bulkactions">
                <select name="filter-type" id="filter-by-type">
                    <option value="0">All types</option>
                    <?php foreach ( $this->_user_fields_mapping as $field_id => $field_data ): ?>
                    <?php $selected = ( $_REQUEST['filter-type'] == $field_id ) ? ' selected' : ''; ?>
                    <option value="<?php echo $field_id; ?>"<?php echo $selected; ?>><?php echo $field_data['name']; ?></option>
                    <?php endforeach; ?>
                </select>
                <input type="submit" class="button">
                </div>
                <?php
        }
    }

    function search_box( $text, $input_id ) {
        if ( empty( $_REQUEST['s'] ) && !$this->has_items() ) {
            return;
        }

        $input_id = $input_id . '-search-input';

        if ( ! empty( $_REQUEST['orderby'] ) ) {
            echo '<input type="hidden" name="orderby" value="' . esc_attr( $_REQUEST['orderby'] ) . '" />';
        }

        if ( ! empty( $_REQUEST['order'] ) ) {
            echo '<input type="hidden" name="order" value="' . esc_attr( $_REQUEST['order'] ) . '" />';
        }

        if ( ! empty( $_REQUEST['post_mime_type'] ) ) {
            echo '<input type="hidden" name="post_mime_type" value="' . esc_attr( $_REQUEST['post_mime_type'] ) . '" />';
        }

        if ( ! empty( $_REQUEST['detached'] ) ) {
            echo '<input type="hidden" name="detached" value="' . esc_attr( $_REQUEST['detached'] ) . '" />';
        }
        ?>
        <p class="search-box">
            <label class="screen-reader-text" for="<?php echo $input_id ?>"><?php echo $text; ?>:</label>
            <input type="search" id="<?php echo $input_id ?>" name="s" value="<?php _admin_search_query(); ?>" />
            <?php submit_button( $text, 'button', false, false, ['id' => 'search-submit'] ); ?>
        </p>
        <?php
    }
}

Answer 1

At this moment, the only solution for me is to switch form method to GET and remove _wp_http_referer from $_SERVER['REQUEST_URI'] with remove_query_arg() in prepare_items() function.

More detailed info in this answer.

Answer 2

Add the following code just above the prepare_items() function

if ( ! empty( $_REQUEST['_wp_http_referer'] && ! empty( $_SERVER['REQUEST_URI'] ) ) ) {
    $url = esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ) );
    $url = remove_query_arg( array( '_wp_http_referer', '_wpnonce' ), $url );

    wp_safe_redirect( $url );

    exit;
}