@propulso: Just saw your comments now.
Here is the full contents of my special-mail-tags.php:
<?php
/**
** Filters for Special Mail Tags
**/
add_filter( 'wpcf7_special_mail_tags', 'wpcf7_special_mail_tag', 10, 2 );
function wpcf7_special_mail_tag( $output, $name ) {
// For backwards compat.
$name = preg_replace( '/^wpcf7\./', '_', $name );
if ( '_remote_ip' == $name )
$output = preg_replace( '/[^0-9a-f.:, ]/', '', $_SERVER['REMOTE_ADDR'] );
elseif ( '_url' == $name )
$output = get_option( 'home' ) . wpcf7_get_request_uri();
elseif ( '_date' == $name )
$output = date_i18n( get_option( 'date_format' ) );
elseif ( '_time' == $name )
$output = date_i18n( get_option( 'time_format' ) );
return $output;
}
add_filter( 'wpcf7_special_mail_tags', 'wpcf7_special_mail_tag_for_post_data', 10, 2 );
function wpcf7_special_mail_tag_for_post_data( $output, $name ) {
if ( ! isset( $_POST['_wpcf7_unit_tag'] ) || empty( $_POST['_wpcf7_unit_tag'] ) )
return $output;
if ( ! preg_match( '/^wpcf7-f(\d+)-p(\d+)-o(\d+)$/', $_POST['_wpcf7_unit_tag'], $matches ) )
return $output;
$post_id = (int) $matches[2];
if ( ! $post = get_post( $post_id ) )
return $output;
$user = new WP_User( $post->post_author );
// For backwards compat.
$name = preg_replace( '/^wpcf7\./', '_', $name );
if ( '_post_id' == $name )
$output = (string) $post->ID;
elseif ( '_post_name' == $name )
$output = $post->post_name;
elseif ( '_post_title' == $name )
$output = $post->post_title;
elseif ( '_post_url' == $name )
$output = get_permalink( $post->ID );
elseif ( '_post_author' == $name )
$output = $user->display_name;
elseif ( '_post_author_email' == $name )
$output = $user->user_email;
return $output;
}
add_filter( 'wpcf7_special_mail_tags', 'wpcf7_special_mail_tag_userdata', 10, 2 );
function wpcf7_special_mail_tag_userdata( $output, $name ) {
// For backwards compat.
$name = preg_replace( '/^wpcf7\./', '_', $name );
global $current_user;
if ( 'user_login' == $name )
$output = $current_user->user_login;
return $output;
}
?>
I hope it helps; I haven’t encountered that error.
It seems that that kind of error can be related to spaces before and/or after PHP code in various files:
https://www.hongkiat.com/blog/wordpress-error-warning-cannot-modify-header-information/
