Question

我有一个html表单，用户需要选择数据库中不能存在的关键字。就像检查域是否存在一样。

如果关键字存在，我想在同一页面上（在输入字段的顶部）回显该关键字是否可用。

修改1

<?php
//Start session
session_start();

//Include database connection details
require_once('config.php');

//Array to store validation errors
$errmsg_arr = array();

//Validation error flag
$errflag = false;

//Connect to mysql server
$link = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD);
if(!$link) {
    die('Failed to connect to server: ' . mysql_error());
}

//Select database
$db = mysql_select_db(DB_DATABASE);
if(!$db) {
    die("Unable to select database");
}

//Function to sanitize values received from the form. Prevents SQL injection
function clean($str) {
    $str = @trim($str);
    if(get_magic_quotes_gpc()) {
        $str = stripslashes($str);
    }
    return mysql_real_escape_string($str);
}

//Sanitize the POST values
$email = clean($_POST['email']);

//Input Validations
if($email == '') {
    $errmsg_arr[] = 'Email missing';
    $errflag = true;
}

//Check for duplicate login ID
if($email != '') {
    $qry = "SELECT * FROM members WHERE email='$email'";
    $result = mysql_query($qry);
    if($result) {
        if(mysql_num_rows($result) > 0) {
            $errmsg_arr[] = 'Email already in use';
            $errflag = true;
        }
        @mysql_free_result($result);
    }
    else {
        die("Query failed");
    }
}

//If there are input validations, redirect back to the registration form
if($errflag) {
    $_SESSION['ERRMSG_ARR'] = $errmsg_arr;
    session_write_close();
    header("location: register-form.php");
    exit();
}

if() {
    header("location: samepage.php");
    exit();
}else {
    die("Query failed");
}
?>

这是html：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Login Form</title>
<link href="loginmodule.css" rel="stylesheet" type="text/css" />
</head>
<body>
<?php
if( isset($_SESSION['ERRMSG_ARR']) && is_array($_SESSION['ERRMSG_ARR']) && count($_SESSION['ERRMSG_ARR']) >0 ) {
    echo '<ul class="err">';
    foreach($_SESSION['ERRMSG_ARR'] as $msg) {
        echo '<li>',$msg,'</li>'; 
    }
    echo '</ul>';
    unset($_SESSION['ERRMSG_ARR']);
}
?>
<form id="loginForm" name="loginForm" method="post" action="register-exec.php">
<table width="300" border="0" align="center" cellpadding="2" cellspacing="0">
<tr>
  <th>First Name </th>
  <td><input name="email" type="text" class="textfield" id="email" /></td>
</tr>
  <td><input type="submit" name="Submit" value="Register" /></td>
</tr>
</table>
</form>
</body>
</html>

我不知道在php的最后一个if语句中该怎么做。任何人都可以帮我这个代码吗？

修改2

<?php
//Start session
session_start();

require_once('config.php');

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}

if(count($_POST) > 0){
//Array to store validation errors
$errmsg_arr = array();

//Validation error flag
$errflag = false;

$email = $conn->real_escape_string($_POST['email']);

if($email == '') {
    $errmsg_arr[] = 'Email missing';
    $errflag = true;
}

$sql = "SELECT * FROM members WHERE email = '$email'";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    $errmsg_arr[] = 'Email already in use';
    $errflag = true;
} 
else 
{
    $errflag = false; // if record not exist.
}

}

$conn->close();

?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Login Form</title>
<link href="loginmodule.css" rel="stylesheet" type="text/css" />
</head>
<body>
<?php
if($errflag){
echo implode(",", $errmsg_arr); // if any error found print error array and use your error stuff like redirection as you are using.
}
else{ 
echo "Available"; // else print Available message or use your stuff.
} 
?>
<form id="loginForm" name="loginForm" method="post" action="register-exec.php">
<table width="300" border="0" align="center" cellpadding="2" cellspacing="0">
<tr>
  <th>Email </th>
  <td><input name="email" type="text" class="textfield" id="email" /></td>
</tr>
  <td><input type="submit" name="Submit" value="Check" /></td>
</tr>
</table>
</form>
</body>
</html>

如何安全地检查sql和echo中的用户输入（如果可用或不在同一页面上）

0 个答案: