A comprehensive test of the validity of an email

We often hope that friends who visit your website can leave an email.
But a lot of people are going to fight, causing the manager to bother,
The following class can be used to check whether email is valid or not.

?
Class Cemail {
var $email _regular_expression= "^" ([a-z0-9_]|\-|\.) +@ (([a-z0-9_]|\-) +\.) +[a-z]{2,4}$ ";
var $timeout = 0;
var $localhost = "";
var $localuser = "";

Function getline ($connection)
{
for ($line = "";;)
{
if (feof ($connection))
return (0);
$line. =fgets ($connection, 100);
$length =strlen ($line);
if ($length >=2
&& substr ($line, $length -2,2) = = "RN")
Return (substr ($line, 0, $length-2));
}
}

Function putline ($connection, $line)
{
Return (Fputs ($connection, "$linern"));
}

Function Verifyrule ($email)
{
Return (eregi ($this->email_regular_expression, $email)!=0);
}

Function validateemailhost ($email, $hosts =0)
{
if (! $this->verifyrule ($email))
return (0);
$user =strtok ($email, "@");
$domain =strtok ("");
if (GETMXRR ($domain,& $hosts,& $weights))
{
$mxhosts =array ();
for ($host =0; $host <count ($hosts); $host + +)
$mxhosts [$weights [$host]]= $hosts [$host];
Ksort ($mxhosts);
For (Reset ($mxhosts), $host =0 $host <count ($mxhosts); Next ($mxhosts), $host + +)
$hosts [$host]= $mxhosts [Key ($mxhosts)];
}
Else
{
$hosts =array ();
if (strcmp (@gethostbyname ($domain), $domain)!=0)
$hosts []= $domain;
}
Return (count ($hosts)!=0);
}

Function verifyresultlines ($connection, $code)
{
while (($line = $this->getline ($connection)))
{
if (!strcmp (Strtok ($line, ""), $code))
return (1);
if (strcmp (Strtok ($line, "-"), $code))
return (0);
}
Return (-1);
}

Function Verifyonline ($email)
{
if (! $this->validateemailhost ($email,& $hosts))
return (0);
if (!strcmp ($localhost = $this->localhost, "")
&&!strcmp ($localhost =getenv ("SERVER_NAME"), "")
&&!strcmp ($localhost =getenv ("HOST"), "")
$localhost = "localhost";
if (!strcmp ($localuser = $this->localuser, "")
&&!strcmp ($localuser =getenv ("USERNAME"), "")
&&!strcmp ($localuser =getenv ("USER"), "")
$localuser = "root";
for ($host =0; $host <count ($hosts); $host + +)
{
if ($connection = ($this->timeout fsockopen ($hosts [$host],25,& $errno,& $error, $this->timeout): Fsockopen ($hosts [$host],25)))
{
if ($this->verifyresultlines ($connection, ">0")
&& $this->putline ($connection, "HELO $localhost")
&& $this->verifyresultlines ($connection, ">0")
&& $this->putline ($connection, "MAIL from: < $localuser @ $localhost >")
&& $this->verifyresultlines ($connection, ">0")
&& $this->putline ($connection, "RCPT to: < $email >")
&& ($result = $this->verifyresultlines ($connection, ">=0"))
{
Fclose ($connection);
return ($result);
}
Fclose ($connection);
}
}
Return (-1);
}

function Verify ($email, $type =0) {
if ($type ==0) return $this->verifyrule ($email);
else return $this->verifyonline ($email);

}

};


?>


Usage:
$m =new Cemail;
Just check the language method
if ($m->verify ("jerry@mail.jerry.com.tw", 0)) echo "valid";
else echo "ineffective";

Check to see if there's a real email.
if ($m->verify ("jerry@mail.jerry.com.tw", 1)) echo "valid";
else echo "ineffective";