php - 如何使用 mysqli_fetch_array 从 MySQL 列中获取数组

Question

我正在尝试编写 IP 禁令。用户IP存储在数据库中。我可以手动将该用户 IP 添加到黑名单。不幸的是，下面的代码不起作用。我认为问题在于从数据库中获取数组。

$ip = $_SERVER['REMOTE_ADDR'];
$bannedips = array();
$notBanned = true; //later used to check, if ip is banned

$sql = "SELECT ip FROM ipban";
$result = mysqli_query($conn, $result);
while($row = mysql_fetch_array($result, MYSQL_NUM)){
    $bannedips[] = $row;
}
if (in_array($ip, $bannedips)) {
    $notBanned = false;
}

Answer 1

出于性能原因，您应该只搜索 ip 而不是查询所有条目

$ip = $_SERVER['REMOTE_ADDR'];
$notBanned = true; //later used to check, if ip is banned

$sql = "SELECT ip FROM ipban WHERE ip = ?";
if ($stmt = mysqli_prepare($conn, $sql)) {
    /* bind parameters for markers */
    mysqli_stmt_bind_param($stmt, "s", $ip);

    if($result = mysqli_query($conn, $sql)){
        $notBanned = false;
        mysqli_free_result($result);
    }
}

面向对象的风格应该是:

$mysqli = new mysqli(/* Whatever needed to establish connection */);
$ip = $_SERVER['REMOTE_ADDR'];
$notBanned = true; //later used to check, if ip is banned

$sql = "SELECT ip FROM ipban WHERE ip = ?";

if ($stmt = $mysqli->prepare($sql)){
    $stmt->bind_param("s", $ip);
    $stmt->execute();
    if($stmt && $stmt->num_rows > 0){
        $notBanned = false;
    }
}