php 关注实现

PHP 实现关注功能的方法

实现关注功能通常涉及用户之间的关系管理，以下是几种常见的实现方式：

数据库设计 创建用户表和关注关系表，关注关系表通常包含关注者ID和被关注者ID两个字段：

CREATE TABLE users (
    id INT PRIMARY KEY AUTO_INCREMENT,
    username VARCHAR(50) NOT NULL
);

CREATE TABLE follows (
    follower_id INT,
    followed_id INT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY (follower_id, followed_id),
    FOREIGN KEY (follower_id) REFERENCES users(id),
    FOREIGN KEY (followed_id) REFERENCES users(id)
);

关注操作实现 使用PHP处理关注请求，检查是否已关注并执行插入操作：

function followUser($followerId, $followedId) {
    $pdo = new PDO('mysql:host=localhost;dbname=your_db', 'username', 'password');
    $stmt = $pdo->prepare("INSERT IGNORE INTO follows (follower_id, followed_id) VALUES (?, ?)");
    $stmt->execute([$followerId, $followedId]);
    return $stmt->rowCount() > 0;
}

取消关注实现 从关注关系表中删除对应记录：

function unfollowUser($followerId, $followedId) {
    $pdo = new PDO('mysql:host=localhost;dbname=your_db', 'username', 'password');
    $stmt = $pdo->prepare("DELETE FROM follows WHERE follower_id = ? AND followed_id = ?");
    $stmt->execute([$followerId, $followedId]);
    return $stmt->rowCount() > 0;
}

检查关注状态 查询两个用户之间是否存在关注关系：

function isFollowing($followerId, $followedId) {
    $pdo = new PDO('mysql:host=localhost;dbname=your_db', 'username', 'password');
    $stmt = $pdo->prepare("SELECT COUNT(*) FROM follows WHERE follower_id = ? AND followed_id = ?");
    $stmt->execute([$followerId, $followedId]);
    return $stmt->fetchColumn() > 0;
}

获取关注列表 查询某个用户关注的所有用户：

function getFollowingList($userId) {
    $pdo = new PDO('mysql:host=localhost;dbname=your_db', 'username', 'password');
    $stmt = $pdo->prepare("SELECT u.id, u.username FROM follows f JOIN users u ON f.followed_id = u.id WHERE f.follower_id = ?");
    $stmt->execute([$userId]);
    return $stmt->fetchAll(PDO::FETCH_ASSOC);
}

获取粉丝列表 查询关注某个用户的所有用户：

function getFollowerList($userId) {
    $pdo = new PDO('mysql:host=localhost;dbname=your_db', 'username', 'password');
    $stmt = $pdo->prepare("SELECT u.id, u.username FROM follows f JOIN users u ON f.follower_id = u.id WHERE f.followed_id = ?");
    $stmt->execute([$userId]);
    return $stmt->fetchAll(PDO::FETCH_ASSOC);
}

性能优化建议

对于大型社交平台，关注系统可能需要考虑以下优化措施：

缓存策略 使用Redis缓存热门用户的关注关系，减少数据库查询压力：

function getCachedFollowingCount($userId) {
    $redis = new Redis();
    $redis->connect('127.0.0.1', 6379);
    $key = "user:{$userId}:following_count";

    if (!$redis->exists($key)) {
        $count = getFollowingCountFromDB($userId);
        $redis->set($key, $count, 3600); // 缓存1小时
        return $count;
    }

    return $redis->get($key);
}

批量处理 当需要处理大量关注关系时，使用批量插入提高效率：

function batchFollow($followerId, $followedIds) {
    $pdo = new PDO('mysql:host=localhost;dbname=your_db', 'username', 'password');
    $placeholders = implode(',', array_fill(0, count($followedIds), '?'));
    $values = array_merge([$followerId], $followedIds);

    $sql = "INSERT IGNORE INTO follows (follower_id, followed_id) 
            SELECT ? AS follower_id, id FROM users WHERE id IN ($placeholders)";

    $stmt = $pdo->prepare($sql);
    $stmt->execute($values);
    return $stmt->rowCount();
}

分页查询 对于关注/粉丝列表实现分页功能：

function getPaginatedFollowing($userId, $page = 1, $perPage = 20) {
    $offset = ($page - 1) * $perPage;
    $pdo = new PDO('mysql:host=localhost;dbname=your_db', 'username', 'password');

    $stmt = $pdo->prepare("SELECT u.id, u.username FROM follows f 
                          JOIN users u ON f.followed_id = u.id 
                          WHERE f.follower_id = ? 
                          LIMIT ? OFFSET ?");
    $stmt->bindValue(1, $userId, PDO::PARAM_INT);
    $stmt->bindValue(2, $perPage, PDO::PARAM_INT);
    $stmt->bindValue(3, $offset, PDO::PARAM_INT);
    $stmt->execute();

    return $stmt->fetchAll(PDO::FETCH_ASSOC);
}

安全考虑

实现关注功能时需要注意以下安全事项：

输入验证 对所有用户输入进行验证和过滤，防止SQL注入：

$followerId = filter_input(INPUT_POST, 'follower_id', FILTER_VALIDATE_INT);
$followedId = filter_input(INPUT_POST, 'followed_id', FILTER_VALIDATE_INT);

if (!$followerId || !$followedId) {
    http_response_code(400);
    echo json_encode(['error' => 'Invalid user IDs']);
    exit;
}

权限检查 确保用户只能操作自己的关注关系：

session_start();
if ($_SESSION['user_id'] != $followerId) {
    http_response_code(403);
    echo json_encode(['error' => 'Unauthorized operation']);
    exit;
}

防刷机制 限制用户频繁关注/取消关注操作：

function canPerformFollowAction($userId) {
    $redis = new Redis();
    $redis->connect('127.0.0.1', 6379);
    $key = "user:{$userId}:follow_actions";
    $count = $redis->incr($key);

    if ($count == 1) {
        $redis->expire($key, 60); // 60秒窗口
    }

    return $count <= 30; // 每分钟最多30次操作
}