php站内发信

<?php
try {
    // 数据库连接
    $conn = new PDO("mysql:host=localhost;dbname=test", "username", "password");
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 消息内容过滤
    $message = htmlspecialchars(trim($_POST['message']), ENT_QUOTES);

    // 插入消息到数据库
    $stmt = $conn->prepare("INSERT INTO messages (sender_id, receiver_id, content) VALUES (?, ?, ?)");
    $stmt->execute([$sender_id, $receiver_id, $message]);

    echo "消息发送成功";
} catch (PDOException $e) {
    echo "消息发送失败: " . $e->getMessage();
}
?>

<?php
// 使用缓存机制
$cacheKey = 'messages_' . $user_id;
$messages = cache_get($cacheKey);

if (!$messages) {
    $stmt = $conn->prepare("SELECT * FROM messages WHERE receiver_id = ?");
    $stmt->execute([$user_id]);
    $messages = $stmt->fetchAll(PDO::FETCH_ASSOC);
    cache_set($cacheKey, $messages, 3600); // 缓存1小时
}
?>

<?php
// 检查消息是否已发送
$stmt = $conn->prepare("SELECT COUNT(*) FROM messages WHERE sender_id = ? AND receiver_id = ? AND content = ?");
$stmt->execute([$sender_id, $receiver_id, $message]);
$count = $stmt->fetchColumn();

if ($count == 0) {
    // 插入消息到数据库
    $stmt = $conn->prepare("INSERT INTO messages (sender_id, receiver_id, content) VALUES (?, ?, ?)");
    $stmt->execute([$sender_id, $receiver_id, $message]);
    echo "消息发送成功";
} else {
    echo "消息已发送";
}
?>