HttpResponse::getHeader — Get header
Get header(s) about to be sent.
This may not work as expected with the following SAPI(s): Apache2 w/PHP < 5.1.3.
specifies the name of the header to read;
if empty or omitted, an associative array with all headers will be returned
Returns either a string containing the value of the header matching name,
FALSE on failure, or an associative array with all headers.