Get html of https after logging in - php

Question

I would like to get the html of the page. After some google-ing, i found following code, which isn't working.
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_USERPWD, "$username:$passwd");
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
$output = curl_exec($ch);
$info = curl_getinfo($ch);
curl_close($ch);
echo $output;
edit: something like this then:
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, '');
curl_setopt($ch, CURLOPT_POSTFIELDS,'username='.urlencode($username).'&passwd='.urlencode($passwd));
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_COOKIEJAR, "/tmp/my_cookies.txt");
curl_setopt($ch, CURLOPT_COOKIEFILE, "/tmp/my_cookies.txt");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt( $ch, CURLOPT_SSL_VERIFYPEER, false );
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3");
curl_setopt($ch, CURLOPT_REFERER, "");
$output = curl_exec($ch);
echo $output
This just shows the target page, it doesn't log in, nor does it return the html code.
edit 2: now tried with $data = array('username' => $username, 'passwd' => $passwd); and curl_setopt($ch, CURLOPT_POSTFIELDS,$data);
This shows the same as above + an error: Request Entity Too Large

Answer 1

That page does not use HTTP Basic Authentication.
You need to make an HTTP request to match what submitting the form would sent, then you need to process the response (which will probably involve storing cookies).