How to send and receive headers via PHP

Question

I'd like to study how headers are sent and received.

I know about PHP's header function and think I can just look at an actual request header (e.g. using Firebug) and make identical requests to a server (including spoofing the User-Agent). Is this correct?

The other problem is how do I get the header responses back? I want to analyze the response.

Thanks.

EDIT:

@Tatu, here's the code I ran:

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, "http://www.google.com/"); curl_setopt($ch, CURLOPT_HEADER, 0); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (X11; U; Linux x86_64; en-US) AppleWebKit/540.0 (KHTML, like Gecko) Ubuntu/10.10 Chrome/8.1.0.0 Safari/540.0');

$result = curl_exec($ch); curl_close($ch);

header('Content-type: text/plain'); echo($result);

Answer 1

If you want to send headers yourself, without using cURL, check out sockets in PHP.

http://php.net/sockets