php实现主动关注

实现用户主动关注功能的 PHP 方法

数据库设计 创建关注关系表（例如 user_follows），包含以下字段：

• follower_id：关注者用户ID
• followed_id：被关注者用户ID
• created_at：关注时间戳

CREATE TABLE user_follows (
    follower_id INT NOT NULL,
    followed_id INT NOT NULL,
    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)
);

关注操作处理 在PHP中处理关注请求的代码示例：

// 假设已获取当前用户ID和被关注用户ID
$followerId = $_SESSION['user_id'];
$followedId = $_POST['user_to_follow'];

// 检查是否已关注
$checkStmt = $pdo->prepare("SELECT COUNT(*) FROM user_follows WHERE follower_id = ? AND followed_id = ?");
$checkStmt->execute([$followerId, $followedId]);
$alreadyFollowing = $checkStmt->fetchColumn();

if (!$alreadyFollowing) {
    // 执行关注操作
    $insertStmt = $pdo->prepare("INSERT INTO user_follows (follower_id, followed_id) VALUES (?, ?)");
    $success = $insertStmt->execute([$followerId, $followedId]);

    if ($success) {
        // 关注成功处理
        echo json_encode(['status' => 'success']);
    } else {
        // 错误处理
        echo json_encode(['status' => 'error', 'message' => '关注失败']);
    }
} else {
    // 已关注处理
    echo json_encode(['status' => 'info', 'message' => '已关注该用户']);
}

取消关注实现 添加取消关注功能的PHP代码：

$deleteStmt = $pdo->prepare("DELETE FROM user_follows WHERE follower_id = ? AND followed_id = ?");
$success = $deleteStmt->execute([$followerId, $followedId]);

if ($success && $deleteStmt->rowCount() > 0) {
    echo json_encode(['status' => 'success']);
} else {
    echo json_encode(['status' => 'error', 'message' => '取消关注失败']);
}

前端交互实现 使用AJAX处理关注按钮点击：

$('.follow-btn').click(function() {
    const userId = $(this).data('user-id');
    const isFollowing = $(this).hasClass('following');

    $.post(isFollowing ? 'unfollow.php' : 'follow.php', 
        { user_to_follow: userId },
        function(response) {
            if (response.status === 'success') {
                $(this).toggleClass('following');
                $(this).text(isFollowing ? '关注' : '已关注');
            }
        }
    );
});

安全性考虑

• 验证用户登录状态
• 防止SQL注入（使用预处理语句）
• 检查用户是否存在
• 限制用户不能关注自己

// 验证示例
if ($followerId == $followedId) {
    http_response_code(400);
    echo json_encode(['status' => 'error', 'message' => '不能关注自己']);
    exit;
}

if (!isset($_SESSION['user_id'])) {
    http_response_code(401);
    echo json_encode(['status' => 'error', 'message' => '请先登录']);
    exit;
}

性能优化

• 为关注关系表创建适当的索引
• 考虑使用缓存存储关注关系
• 批量查询关注状态以减少数据库查询

CREATE INDEX idx_follower ON user_follows(follower_id);
CREATE INDEX idx_followed ON user_follows(followed_id);