WordPress插件在使用wp_redirect时抛出警告

Question

I am developing a plugin where user will submit a form. The form submits to the same page. Form data handling code is implemented by checking the condition-

if ( !empty( $_POST['action'] ) && $_POST['action'] == 'customer_add_new')

Then the data is validated and entered to database using $wpdb->insert.

After that, I want to pass a variable to the URL, so that success message can be displayed and user can be stopped from re-submitting the form by refreshing the page. For that, I used-

$url = add_query_arg( array(
    'customer_add_new' => 'success'
    ) );
wp_redirect( $url );
exit();

But this code is throwing the following error-

Warning: Cannot modify header information - headers already sent by (output started at E:\wamp\www\cp_plugin\wp-includes\class.wp-scripts.php:343) in E:\wamp\www\cp_plugin\wp-includes\pluggable.php on line 1216

I have successfully used the same code in the theme for this very same project. But the functionality was better suited for a plugin, than for a theme.

Answer 1

hook admin_post will help you. Works the same as admin-ajax.php.

Change form action to <?php echo admin_url('admin-post.php'); ?> and create hooks:

add_action( 'admin_post_{action}', 'funct' );
add_action( 'admin_post_nopriv_{action}', 'funct' );

function funct() {
    if ( wp_verify_nonce( 'some_nonce', 'some_action' ) ) {
        // Your code using $_POST
        // And create wp_redirect();
    }
}

This might help you.