php 站内消息 实现

站内消息系统设计要点

数据库表设计需要包含消息表（messages），通常包含字段：id、sender_id、receiver_id、content、created_at、is_read等。用户表（users）用于关联发送者和接收者。

消息表建议结构：

CREATE TABLE `messages` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `sender_id` int(11) NOT NULL,
  `receiver_id` int(11) NOT NULL,
  `subject` varchar(255) DEFAULT NULL,
  `content` text NOT NULL,
  `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `is_read` tinyint(1) DEFAULT '0',
  PRIMARY KEY (`id`),
  KEY `sender_id` (`sender_id`),
  KEY `receiver_id` (`receiver_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

消息发送功能实现

创建消息发送表单（send_message.php）：

<form action="send_message_process.php" method="post">
    <input type="hidden" name="sender_id" value="<?php echo $_SESSION['user_id']; ?>">
    <div>
        <label>接收者ID：</label>
        <input type="text" name="receiver_id" required>
    </div>
    <div>
        <label>主题：</label>
        <input type="text" name="subject">
    </div>
    <div>
        <label>内容：</label>
        <textarea name="content" required></textarea>
    </div>
    <button type="submit">发送</button>
</form>

处理发送逻辑（send_message_process.php）：

<?php
session_start();
require 'db_connect.php';

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $senderId = $_POST['sender_id'];
    $receiverId = $_POST['receiver_id'];
    $subject = htmlspecialchars($_POST['subject']);
    $content = htmlspecialchars($_POST['content']);

    $stmt = $pdo->prepare("INSERT INTO messages (sender_id, receiver_id, subject, content) VALUES (?, ?, ?, ?)");
    $stmt->execute([$senderId, $receiverId, $subject, $content]);

    header("Location: messages.php?status=sent");
    exit;
}
?>

消息接收与展示

获取用户收件箱（inbox.php）：

<?php
session_start();
require 'db_connect.php';

$userId = $_SESSION['user_id'];
$stmt = $pdo->prepare("SELECT m.*, u.username as sender_name 
                      FROM messages m 
                      JOIN users u ON m.sender_id = u.id 
                      WHERE m.receiver_id = ? 
                      ORDER BY m.created_at DESC");
$stmt->execute([$userId]);
$messages = $stmt->fetchAll(PDO::FETCH_ASSOC);
?>

<ul>
<?php foreach ($messages as $message): ?>
    <li class="<?php echo $message['is_read'] ? 'read' : 'unread'; ?>">
        <strong><?php echo $message['sender_name']; ?></strong>
        <span><?php echo $message['subject']; ?></span>
        <p><?php echo $message['content']; ?></p>
        <small><?php echo $message['created_at']; ?></small>
    </li>
<?php endforeach; ?>
</ul>

消息状态更新

标记消息为已读（mark_as_read.php）：

<?php
session_start();
require 'db_connect.php';

if (isset($_GET['message_id'])) {
    $messageId = $_GET['message_id'];
    $userId = $_SESSION['user_id'];

    // 验证消息属于当前用户
    $stmt = $pdo->prepare("UPDATE messages SET is_read = 1 WHERE id = ? AND receiver_id = ?");
    $stmt->execute([$messageId, $userId]);

    header("Location: inbox.php");
    exit;
}
?>

实时消息提醒

使用AJAX轮询检查新消息：

setInterval(function() {
    $.ajax({
        url: 'check_new_messages.php',
        type: 'GET',
        success: function(response) {
            if (response.count > 0) {
                $('#message-notification').text(response.count).show();
            } else {
                $('#message-notification').hide();
            }
        }
    });
}, 30000); // 每30秒检查一次

后端检查新消息（check_new_messages.php）：

<?php
session_start();
require 'db_connect.php';

$userId = $_SESSION['user_id'];
$stmt = $pdo->prepare("SELECT COUNT(*) as count FROM messages WHERE receiver_id = ? AND is_read = 0");
$stmt->execute([$userId]);
$result = $stmt->fetch(PDO::FETCH_ASSOC);

header('Content-Type: application/json');
echo json_encode($result);
?>

安全与优化建议

对用户输入进行严格过滤和验证，防止SQL注入和XSS攻击。使用预处理语句处理数据库查询。

添加分页功能处理大量消息：

$page = isset($_GET['page']) ? (int)$_GET['page'] : 1;
$limit = 10;
$offset = ($page - 1) * $limit;

$stmt = $pdo->prepare("SELECT m.*, u.username as sender_name 
                      FROM messages m 
                      JOIN users u ON m.sender_id = u.id 
                      WHERE m.receiver_id = ? 
                      ORDER BY m.created_at DESC
                      LIMIT ? OFFSET ?");
$stmt->execute([$userId, $limit, $offset]);

考虑添加消息删除功能：

$stmt = $pdo->prepare("DELETE FROM messages WHERE id = ? AND (sender_id = ? OR receiver_id = ?)");
$stmt->execute([$messageId, $userId, $userId]);