过滤器comment_form_field_comment 添加select 带有label. comment_post 保存值

过滤器comment_text 显示注释的值

示例代码：

add_filter( \'comment_form_field_comment\', function( $field ) {

    global $wp_roles;

    $user = wp_get_current_user();

    $select = \'<p><label for="roleselect">Your role:</label>
    <select name="prefix_role" id="roleselect">
    <option value="">Select a role</option>\';

    foreach ( $wp_roles->roles as $key => $role )
        $select .= sprintf(
            \'<option value="%1$s" %2$s>%3$s</option>\',
            esc_attr( $key ),
            ( in_array( $key, $user->roles) ? \'selected\' : \'\' ),
            esc_html( $role[\'name\'] )
        );

    $select .= \'</select></p>\';

    return $select . $field;
});

add_action( \'comment_post\', function( $comment_ID ) {

    $roles = new WP_Roles;
    $role_keys = array_keys( $roles->roles );

    if ( isset ( $_POST[\'prefix_role\'] ) and in_array( $_POST[\'prefix_role\'], $role_keys ) )
        update_comment_meta( $comment_ID, \'prefix_role\', $_POST[\'prefix_role\'] );
});

add_filter( \'comment_text\', function( $text, $comment ) {

    if ( $role = get_comment_meta( $comment->comment_ID, \'prefix_role\', TRUE ) )
        $text = "Role: $role<br> $text";

    return $text;
}, 10, 2 );

更新我已经重写了代码以使用真正的MVC模式。解释如下。

插件标题

<?php # -*- coding: utf-8 -*-
namespace WPSE;
/**
 * Plugin Name: Comment Meta Demo
 * Description: Create, save and display a comment meta field. Here, a commentator can select a role.
 * Plugin URI:  http://wordpress.stackexchange.com/q/101579/73
 * Version:     2013.06.06
 * Author:      Fuxia Scholz
 * Licence:     MIT
 * License URI: http://opensource.org/licenses/MIT
 */

\\add_action(
    \'wp_loaded\',
    array( __NAMESPACE__ . \'\\Comment_Meta_Controller\', \'init\' )
);

控制器

/**
 * Controller
 *
 * Assigns Views and models to actions and filters
 */
class Comment_Meta_Controller
{
    /**
     * Callback for add_action(). Creates a new instance.
     *
     * @wp-hook login_init
     */
    public function init()
    {
        return new self;
    }

    /**
     * Set up objects, register footer action callback.
     *
     * @wp-hook login_init
     */
    protected function __construct()
    {

        $data   = new Comment_Meta_Builtin_Roles( \'_comment_role\' );
        // Use this for custom roles instead
        //$data   = new Comment_Meta_Custom_Roles( \'_comment_role\' );
        $input  = new Comment_Meta_Role_Selector( $data );
        $output = new Comment_Meta_Role_Display( $data );

        // remove this if you want to show the select field with
        // do_action( \'comment_role_selector\' );
        \\add_filter( \'comment_form_field_comment\', array ( $input, \'show\' ), 10, 2 );

        \\add_action( \'comment_role_selector\', array ( $input, \'print_select\' ) );

        // remove this if you want to show the select field with
        // do_action( \'comment_role_selector\' );
        \\add_filter( \'comment_text\', array ( $output, \'show\' ), 10, 2 );

        \\add_action( \'comment_role_value\', array ( $output, \'show_action\' ), 10, 2 );

        if ( \'POST\' === $_SERVER[ \'REQUEST_METHOD\' ] )
            \\add_action( \'comment_post\', array ( $data, \'save\' ) );
    }
}

抽象元数据基类

/**
 * Base class for handling comment meta data.
 */
abstract class Comment_Meta_Data_Model
{
    /**
     * Meta key
     *
     * @type string
     */
    protected $key;

    /**
     * Constructor
     *
     * @param string $key
     */
    public function __construct( $key )
    {
        $this->key = $key;
    }

    /**
     * Get current key
     *
     * @return string
     */
    public function get_key()
    {
        return $this->key;
    }

    /**
     * Wrapper for the native get_comment_meta()
     *
     * @param  int    $comment_ID
     * @return string
     */
    public function get_comment_meta( $comment_ID )
    {
        $meta    = \\get_comment_meta( $comment_ID, $this->key, TRUE );
        $allowed = $this->get_allowed_values();

        // get real display value
        if ( isset ( $allowed[ $meta ] ) )
            return $allowed[ $meta ];

        return \'\';
    }

    /**
     * Save comment mate data.
     *
     * @param  int  $comment_ID
     * @return bool
     */
    public function save( $comment_ID )
    {
        $role_keys = array_keys( $this->get_allowed_values() );

        if ( ! isset ( $_POST[ $this->key ] ) )
            return;

        if ( ! in_array( $_POST[ $this->key ], $role_keys ) )
            return;

        return \\update_comment_meta( $comment_ID, $this->key, $_POST[ $this->key ] );
    }

    /**
     * Get user role.
     */
    public function get_current_value()
    {
        $user = \\wp_get_current_user();

        if ( empty ( $user->roles ) )
            return array ();

        return $user->roles;
    }

    /**
     * @return array
     */
    abstract public function get_allowed_values();
}

内置角色的扩展类

/**
 * User roles as comment meta.
 */
class Comment_Meta_Builtin_Roles extends Comment_Meta_Data_Model
{
    /**
     * (non-PHPdoc)
     * @see WPSE.Comment_Meta_Data_Model::get_allowed_values()
     */
    public function get_allowed_values()
    {
        global $wp_roles;

        if ( empty ( $wp_roles ) )
            $wp_roles = new \\WP_Roles;

        $output = array();

        foreach ( $wp_roles->roles as $identifier => $role )
            $output[ $identifier ] = $role[\'name\'];

        return $output;
    }
}

用于自定义选择允许角色的扩展类

/**
 * Custom roles for comment meta.
 */
class Comment_Meta_Custom_Roles extends Comment_Meta_Data_Model
{
    /**
     * (non-PHPdoc)
     * @see WPSE.Comment_Meta_Data_Model::get_allowed_values()
     */
    public function get_allowed_values()
    {
        return array (
            \'teacher\' => \'Teacher\',
            \'student\' => \'Student\'
        );
    }
}

基本评论元视图

/**
 * Base class to show comment meta data.
 */
class Comment_Meta_View
{
    /**
     * Model
     *
     * @type Comment_Meta_Data_Model
     */
    protected $data;

    /**
     * Constructor.
     *
     * @param Comment_Meta_Data_Model $data
     */
    public function __construct( Comment_Meta_Data_Model $data )
    {
        $this->data = $data;
    }
}

使用选择字段作为视图

/**
 * Show role selector from comment meta
 */
class Comment_Meta_Role_Selector extends Comment_Meta_View
{
    /**
     * Add \'select\' field before textarea.
     *
     * @param  string $text_field
     * @return string
     */
    public function show( $text_field )
    {
        return $this->get_select() . $text_field;
    }

    /**
     * Select element.
     *
     * @return string
     */
    public function get_select()
    {
        $allowed = $this->data->get_allowed_values();
        $current = $this->data->get_current_value();
        $key     = $this->data->get_key();

        // is the current value part of the allowed values?
        if ( ! empty ( $current ) && array() !== array_intersect( $allowed, $current ) )
            return $this->get_hidden_field( $key, $current[0] );

        $select = \'<p>\';
        $select .= sprintf( \'<label for="%1$s_id">Your role:</label>
            <select name="%1$s" id="%1$s_id">\',
            $key
        );
        $select .= \'<option value="">Select a role</option>\';

        foreach ( $allowed as $internal => $display )
            $select .= sprintf(
                \'<option value="%1$s">%2$s</option>\',
                \\esc_attr( $internal ),
                \\esc_html( $display )
            );

        return $select . \'</select></p>\';
    }

    /**
     * Print preselcted role as hidden input field.
     *
     * @param  string $name Field name
     * @param  string $role Internal role name
     * @return string
     */
    protected function get_hidden_field( $name, $role )
    {
        return sprintf(
            \'<input type="hidden" name="%1$s" value="%2$s">\',
            $name,
            esc_attr( $role )
        );
    }

    /**
     * Callback for do_action.
     *
     * @wp-hook comment_role_selector
     * @return  void
     */
    public function print_select()
    {
        print $this->get_select();
    }
}

将当前角色显示为视图

/**
 * Show current comment role.
 */
class Comment_Meta_Role_Display extends Comment_Meta_View
{
    /**
     * Add role to comment text.
     *
     * @wp-hook comment_text
     * @param   string $text
     * @param   object $comment
     * @return  string
     */
    public function show( $text, $comment )
    {
        $role = $this->data->get_comment_meta( $comment->comment_ID );

        if ( \'\' !== $role )
            $text = "Role: $role<br> $text";

        return $text;
    }

    /**
     * Print the comment meta value into a template.
     *
     * Usage: <code>do_action( \'comment_role_value\', \'Role: %s<br>\', $comment );
     *
     * @wp-hook comment_role_value
     * @param   string $template
     * @param   object $comment
     * @return  void
     */
    public function show_action( $template, $comment )
    {
        $role = $this->data->get_comment_meta( $comment->comment_ID );

        if ( \'\' !== $role )
            printf( $template, $role );
    }
}

如你所见，我们现在有七节课：

1. Comment_Meta_Controller
   在这里，其他类被结合起来做一些有用的事情
2. Comment_Meta_Data_Model处理注释数据的基类。不能按原样使用，必须扩展
3. Comment_Meta_Builtin_Roles
   扩展Comment_Meta_Data_Model 并使用所有内置角色。我已经在测试中使用了它；您可能应该使用下一个类。更改控制器以执行此操作
4. Comment_Meta_Custom_Roles
   扩展Comment_Meta_Data_Model. 替代方案Comment_Meta_Builtin_Roles.
   如您所见，只需更改一个方法（函数）即可返回自定义角色数组
5. Comment_Meta_View
   输出的基类。不能按原样使用，必须扩展
6. Comment_Meta_Role_Selector
   扩展Comment_Meta_View. 创建select 要素它不知道数据源的任何信息，只从视图中获取其值
7. Comment_Meta_Role_Display
   扩展Comment_Meta_View. 显示注释的当前值

用法show the select field 要么…

什么都不做，让我的默认值来完成工作。然后，选择字段将设置在注释文本字段的正上方

\\add_filter( \'comment_form_field_comment\', array ( $input, \'show\' ), 10, 2 );

…并在评论表单中使用以下代码：

do_action( \'comment_role_selector\' );

至set custom values 对于允许的角色，请删除该行…

    $data   = new Comment_Meta_Builtin_Roles( \'_comment_role\' );

…并取消对以下行的注释。然后编辑Comment_Meta_Custom_Roles.

到change the meta key, 只需更改值\'_comment_role\'. 确保不要使用WordPress的内置键。

仅此而已。