PHP Setting custom header starting with ':'

Question

I need to setup some custom headers start with ":".

$option['headers'][] = ":authority: example.com"; //<-- Here is the problem
$option['headers'][] = "accept-encoding: gzip, deflate, br";
$option['post'] = json_encode(array("Domain"=>"example.com"));
$url = "https://www.google.com";
$ch = curl_init($url);
curl_setopt($ch,CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.62 Safari/537.36");
curl_setopt($ch,CURLOPT_FOLLOWLOCATION,1);
curl_setopt($ch,CURLOPT_COOKIEFILE,"file.cookie");
curl_setopt($ch,CURLOPT_COOKIEJAR,"file.cookie");
curl_setopt($ch,CURLOPT_SSL_VERIFYHOST, 0);
curl_setopt($ch,CURLOPT_SSL_VERIFYPEER, 0);
curl_setopt($ch,CURLOPT_HEADER,0);
curl_setopt($ch,CURLOPT_VERBOSE, true);
curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $option['post']);
curl_setopt($ch, CURLOPT_HTTPHEADER, $option['headers']);
$getdata = curl_exec($ch);

I try to replace the ":" with chr(58) but same problem. I get error 55 and from log "* Failed sending HTTP POST request". If I comment first line is working, but I really need that header. I'm stuck here. Any solutions?

Answer 1

:authority: looks like an HTTP/2 psuedo header, and you can't set them like this with curl. curl will however pass it on itself and it will use the same content as it would set for Host: to make it work the same way, independently of which HTTP version that is eventually used (it will also work with HTTP/3).