public function getHeader($field)
    {
       if (!isset($this->headers[$field])) {
           return null;
       }
       
       return is_array($this->headers[$field]) ? implode(',', $this->headers[$field]) : $this->headers[$field];
    }
public function getHeader($field)
    {
       if (!isset($this->headers[$field])) {
           return null;
       }
       
       return is_array($this->headers[$field]) ? implode(',', $this->headers[$field]) : $this->headers[$field];
    }
public function getHeader ( $ field ) { if ( ! isset ( $ this -> headers [ $ field ] ) ) { return null ; } return is_array ( $ this -> headers [ $ field ] ) ? implode ( ',' , $ this -> headers [ $ field ] ) : $ this -> headers [ $ field ] ; }
Return one field from header

@param string $field Header field name

@return null|string
Return one field from header