Simulate login with PHP_PHP tutorial

People often ask about simulated login. In fact, the principle is very simple. Just save the SessionID. I spent an hour today writing a function for your reference. The header information returned by the website , specific analysis of specific websites.

Source code:

/*
* Get web content
* Parameter: $host [in] string
* Host name (for example: www.etoow.com)
* Parameter: $method [in] string
* Submission method: POST, GET, HEAD... and add corresponding parameters (see RFC1945, RFC2068 for specific syntax)
* Parameter: $str [in] string
* Submitted content
* Parameter: $sessid [in] string
* PHP SESSIONID
*
* @return web page content string
*/
function GetWebContent($host, $method, $str, $sessid = '')
{
$ip = gethostbyname($host);
$fp = fsockopen($ip, 80);
if (!$fp) return;
fputs($fp, "$methodrn");
fputs($fp, "Host: $hostrn");
if (!empty($sessid))
{
fputs($fp, "Cookie: PHPSESSID=$sessid; path=/;rn");
}
if ( substr(trim($method),0, 4) == "POST")
{
fputs($fp, "Content-Length: ". strlen($str) . "rn"); // Don't forget to specify the length
}
fputs($fp, "Content-Type: application/x-www-form-urlencodedrnrn");
if ( substr(trim($method),0, 4) == "POST")
{
fputs($fp, $str."rn");
}
while(!feof($fp))
{
$response .= fgets($fp, 1024);
}
$hlen = strpos($response," "); // Under LINUX it is " "
$header = substr($response, 0, $hlen);
$entity = substr($response, $hlen 4);
if ( preg_match('/PHPSESSID=([0-9a-z] );/i', $header, $matches))
{
$a['sessid'] = $matches[1];
}
if ( preg_match('/Location: ([0-9a-z_?=&#.] )/i', $header, $matches))
{
$a['location'] = $matches[1];
}
$a['content'] = $entity;
fclose($fp);
return $a;
}

/* Construct username and password string */
$str = ("username=test&password=test");
$response = GetWebContent("localhost","POST /login.php HTTP/1.0", $str);
echo $response['location'].$response['content']."
";
echo $response['sessid']."
";
if ( preg_match('/error.php/i',$response['location']))
{
echo "Login failed
";
} else {
echo "Login successful
";
// User.php cannot be accessed because there is no sessid parameter
$response = GetWebContent("localhost","GET /user.php HTTP/1.0", '', '');
echo $response['location']."
"; // Result: error.php?errcode=2

// Can access user.php
$response = GetWebContent("localhost","GET /user.php HTTP/1.0", '', $response['sessid']);
echo $response['location']."
"; // Result: user.php
}
?>