Wordpress - 致命错误:在非对象 $wpdb 上调用成员函数 get_var()

问题描述

我正在尝试根据在帖子设置中输入的密码将用户定向到某个帖子.我几乎有工作代码:

I'm trying to direct users to a certain post based on a password entered in post settings. I have almost working code:

页面上的表单:

<form method="post" action="">
  <input type="password" name="passwordfield">
  <input type="hidden" name="homepagepassword" value="1">
  <input type="submit" value="Submit">
</form>

functions.

Code in functions.

function doPasswordStuff(){
    if(isset($_POST['homepagepassword'])){
    $post_password = $_POST['passwordfield'];
    $post_id = $wpdb->get_var( $wpdb->prepare("SELECT ID FROM $wpdb->posts WHERE post_password = %s", $post_password) );
    $q = new WP_Query( 'p=$post_id' );
    if($q->have_posts()){
        while($q->have_posts()){
            $q->the_post();
            wp_redirect(get_permalink());
            die();
        }
    } else {
        // oh dear, there isnt a post with this 'password', put a redirect to a fallback here
        wp_redirect('http://www.google.com');
        die();
    }
    wp_reset_query();
    }
}
add_action('init','doPasswordStuff');

但是我在这一行遇到了致命错误(致命错误:在非对象上调用成员函数 get_var()):

However I'm getting fatal error (Fatal error: Call to a member function get_var() on a non-object) on this line:

$post_id = $wpdb->get_var( $wpdb->prepare("SELECT ID FROM $wpdb->postsWHERE post_password = %d", $post_password) );

如果有人能看一下，真的会很感激:)谢谢！

If would really appreciate if someone would take a look :) thanks!

推荐答案

在此之前全局化 $wpdb

globalize $wpdb before this

全局 $wpdb

$post_id = $wpdb->get_var( $wpdb->prepare("SELECT id FROM $wpdb->posts WHERE post_password = %s", $post_password) );$q = new WP_Query('p=$post_id');

此外，最好使用小写的表/列名称

Also it is a best practise to use lowercase table/column names

然后像这样重定向

have_posts() ) : $q->the_post();?>

wp_redirect( the_permalink() );

还使用 http 状态代码作为 wp_redirect() 的第二个参数这可能会有所帮助HTTP 状态代码

Also use a http status code as the second parameter to wp_redirect()This might be helpfulHTTP STATUS CODES

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