我想出了一个解决方案，在搜索表单上使用一个隐藏字段，稍后我们将在过滤器中检查该字段，以修改WP的默认搜索/重定向行为。

这是我使用的搜索表单。注意添加了隐藏字段barcode-reader 值为1. 为了测试和演示，我将搜索表单添加到页面模板中。

<form role="search" method="get" class="search-form" action="<?php echo esc_attr( home_url( \'/\' ) ); ?>">
    <label>
    <span class="screen-reader-text"><?php echo _x( \'Search for:\', \'screen reader search label\', \'textdomain\' ); ?></span>
    <div class="input-group">
        <input type="search" class="search-field input-group-field" placeholder="<?php echo esc_attr_x( \'Search...\', \'search placeholder\', \'textdomain\' ); ?>" value="<?php echo get_search_query(); ?>" name="s" title="<?php echo esc_attr_x( \'Search for:\', \'textdomain\' ); ?>" />

        <input type="hidden" value="1" name="barcode-reader" />

        <div class="input-group-button">
            <button type="submit" class="search-submit button" value="<?php echo esc_attr_x( \'Search\', \'search button\', \'textdomain\' ); ?>">Search</button>
        </div>
    </div>
    </label>
</form>

这里，我们将检查条形码扫描仪是否正在使用帮助器功能执行此搜索wpse_is_barcode_search(). 使用helper函数，这样我们就不必在这个实现中使用的多个挂钩之间复制逻辑。

如果我们使用扫描仪进行搜索，我们会将posts_search 筛选并对WP_Query 执行查询之前的实例。

/**
 * Wire up our posts_search filter and change the $query.
 * 
 * @param WP_Query $query The WP_Query instance (passed by reference).
 */
add_action( \'pre_get_posts\', \'wpse_barcode_search_pre_get_posts\' );
function wpse_barcode_search_pre_get_posts( $query ) {
    // Bail if this search is not performed by the barcode scanner.
    if ( ! wpse_is_barcode_search( $query ) ) {
        return;
    }

    // Wire up the filter to modify the search SQL.
    add_filter( \'posts_search\', \'wpse_barcode_posts_search\', 10, 2 );

    // Set posts_per_page to one since we\'re only looking for an exact match anyway.
    $query->set( \'posts_per_page\', 1 );

    // (suggestion) Limit search to a particular post type.
    // $query->set( \'post_type\', array( \'product\', ) );
}

/**
 * Modify search query so that the search term looks for an exact
 * match with the post title.
 *
 * @param string   $search Search SQL for WHERE clause.
 * @param WP_Query $wp_query   The current WP_Query object.
 */
function wpse_barcode_posts_search( $search,  $wp_query ) {
    // We only want the search filter to fire once, so unhook it.
    remove_filter( \'posts_search\', \'wpse_barcode_posts_search\', 10, 2 );

    // Change the search SQL so that it checks if the search is equal to the post title.
    $search = " AND (wp_posts.post_title = \'" . esc_sql( $wp_query->query_vars[\'s\'] ) . "\')";

    return $search;
}

/**
 * Redirect to the permalink of the searched item if it was found using
 * the barcode search.
 *
 * @link https://wordpress.stackexchange.com/a/128578/2807
 */
add_action( \'template_redirect\', \'wpse_barcode_search_success_redirect\' );
function wpse_barcode_search_success_redirect() {
    global $wp_query;
    if ( ! wpse_is_barcode_search( $wp_query ) ) {
        return;
    }

    // If we have a post, redirect to it.
    if ( \'1\' === $wp_query->found_posts ) {
        wp_redirect( get_permalink( $wp_query->posts[\'0\']->ID ) );
        exit;
    }
}

/**
 * Helper function used to determine if a search is performed using
 * the barcode scanner.
 *
 * @uses array $_REQUEST
 * @param object $query
 * @return bool
 */
function wpse_is_barcode_search( $query ) {
    // Bail if $query is not an instance of WP_Query.
    if ( ! ( $query instanceof WP_Query ) ) {
        return false;
    }

    // Bail if this is the admin area.  
    if ( $query->is_admin() ) {
        return false;
    }

    // Bail if this is not the search page or main query.
    if ( ! $query->is_search() || ! $query->is_main_query() ) {
        return false;
    }

    // Bail if this is not our special barcode search.
    if ( ! isset( $_REQUEST[\'barcode-reader\'] ) || \'1\' !== $_REQUEST[\'barcode-reader\'] ) {
        return false;
    }

    return true;
}

风俗template 你有自定义的地方query. 这query 仅搜索一个post 和template 仅显示此post.