我正在尝试写一个插件。我已经使用插件成功地在注册表中添加了一个额外字段。我想检查额外字段中的值是否与任何已注册的用户名匹配。

当我尝试使用预定义的usermeta函数进行验证时。我发现以下错误：

require( \'C:\\wamp\\www\\cpa\\wp-load.php\' )
require_once( \'C:\\wamp\\www\\cpa\\wp-config.php\' )
require_once( \'C:\\wamp\\www\\cpa\\wp-settings.php\' )

我可以在主题模板中完成这项工作。但我想知道如何像在主题文件中一样，在插件中访问WordPress的所有预定义功能。

代码：

//1. Add a new form element...

$referral_username = $_REQUEST[\'referral\'];

add_action(\'register_form\',\'myplugin_register_form\');
function myplugin_register_form (){
    $referral_username = ( isset( $_POST[\'referral_username\'] ) ) ? $_POST[\'referral_username\']: \'\';
    ?>
    <p>
        <label for="referral_username"><?php _e(\'Referral Username\',\'mydomain\') ?><br />
            <input type="text" name="referral_username" id="referral_username" class="input" size="20"value="<?php echo $referral_username = $_REQUEST[\'referral\']; ?>" size="25" />



            </label>
    </p>
    <?php
}

//2. Add validation. In this case, we make sure referral_username is required.
add_filter(\'registration_errors\', \'myplugin_registration_errors\', 10, 3);
function myplugin_registration_errors ($errors, $sanitized_user_login, $user_email) {

    if ( empty( $_POST[\'referral_username\'] ) )
        $errors->add( \'referral_username_error\', __(\'<strong>ERROR</strong>: You must include a Valid Referral User Name. Else leave it blank.\',\'mydomain\') );

    return $errors;
}

//3. Finally, save our extra registration user meta.
add_action(\'user_register\', \'myplugin_user_register\');
function myplugin_user_register ($user_id) {
    if ( isset( $_POST[\'referral_username\'] ) )
        update_user_meta($user_id, \'referral_username\', $_POST[\'referral_username\']);
}


//Test Usermeta

$user = get_userdatabylogin(\'vijay\');
echo $user->ID; // prints the id of the user;

//Test Usermeta

$user = get_userdatabylogin(\'vijay\');
echo $user->ID; // prints the id of the user;

add_action( \'after_setup_theme\', \'test_user_meta\' );
/**
 * Test User meta.
 */
function test_user_meta() {
    $user = get_userdatabylogin(\'vijay\');
    echo $user->ID; // prints the id of the user;
}

require (ABSPATH . WPINC . \'/pluggable.php\');