| public getHeaderLine ( $header ) : string | null | ||
| 리턴 | string | null | A string of values as provided for the given header concatenated together using a comma. If the header does not appear in the message, this method MUST return a null value. |
public function getHeaderLine($header)
{
$value = $this->getHeader($header);
if (empty($value)) {
return null;
}
return implode(',', $value);
}