php - 验证数据库中是否存在输入的用于请求密码的电子邮件

Question

我有以下代码来从数据库中检索用户的密码并通过电子邮件发送给他。如果数据库中存在用户的电子邮件，我就可以成功地向用户发送他的密码。但如果电子邮件不存在，我希望代码能够回显数据库中不存在特定用户的电子邮件。如果在表单中输入无效的电子邮件，我的代码会给出以下结果:

无法添加收件人:@localhost [SMTP:从服务器收到的响应代码无效(代码:555，响应:5.5.2 语法错误。v9sm2318990paz.6)]

我已尝试使用 if-else 语句来实现此目的。这是我写的代码:

<?php

//Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect to server");
mysql_select_db("$db_name")or die("cannot select DB");

// email value sent from HTML form
$email_to=$_POST['email'];

// table name
$tbl_name="registration";

if($mysql1 = "SELECT ID,Email,Password FROM $tbl_name WHERE Email='$email_to' ORDER BY ID DESC ")
{
$selectemail = mysql_query($mysql1);

$shah       =   mysql_fetch_array($selectemail);
$EMAIL      =   $shah['Email'];
$UID        =   $shah['ID'];
$password           =       $shah['Password'];

require_once "/home/computat/php/Mail.php";

$from = "abhishekagrawal.988@gmail.com";
$to = $EMAIL;  

$subject = "Your password for www.computationalphotography.in";
$body    = "Your password for logging on to our website www.computationalphotography.in is:\n$password\r\nIf you have any additional queries, kindly write to us at abhishekagrawal.988@gmail.com\r\n\nThanks & Regards\nThe Computational Photography Team\n";   

    $host = "ssl://smtp.gmail.com";
    $port = "465";
    $username = "abhishekagrawal.988@gmail.com";  //
    $password = "*********";

    $headers = array ('From' => $from,
      'To' => $to,
      'Subject' => $subject);
    $smtp = Mail::factory('smtp',
      array ('host' => $host,
        'port' => $port,
        'auth' => true,
        'username' => $username,
        'password' => $password));

    $mail = $smtp->send($to, $headers, $body);

    if (PEAR::isError($mail)) {
      echo("<p>" . $mail->getMessage() . "</p>");
     } else {
      echo("<p></p>");
     }
}
else{
echo "<b><center>Email not found in the database</center></b>";
}
/*    

Answer 1

使用这个

$mysql1 = mysql_query("SELECT ID,Email,Password FROM $tbl_name WHERE Email='$email_to' ORDER BY ID DESC ");
if(mysql_num_rows($mysql1)){
      //exists in db
}
else{//does not exist}

避免使用mysql_*函数使用mysqli_*或PDO，因为mysql_*正在贬值