基於PHP的即時聊天系統的用戶頭像和個性裝扮設置

<?php
    $allowedExtensions = ['jpg', 'jpeg', 'png']; // 允许上传的图片格式
    $maxFileSize = 2 * 1024 * 1024; // 允许上传的最大文件大小（2MB）
    
    if($_SERVER['REQUEST_METHOD'] == 'POST' && isset($_FILES['avatar'])) {
        $filename = $_FILES['avatar']['name'];
        $fileTmp = $_FILES['avatar']['tmp_name'];
        $fileSize = $_FILES['avatar']['size'];
        $fileError = $_FILES['avatar']['error'];
        
        $fileExtension = strtolower(pathinfo($filename, PATHINFO_EXTENSION)); // 获取文件扩展名
        
        if(in_array($fileExtension, $allowedExtensions) && $fileSize <= $maxFileSize) {
            $newFilename = uniqid() . '.' . $fileExtension; // 生成唯一的文件名
            $destination = 'avatars/' . $newFilename;
            
            if(move_uploaded_file($fileTmp, $destination)) {
                // 头像上传成功，将文件名保存到数据库中的用户信息表中
                $userId = $_SESSION['userId']; // 假设当前登录用户的ID为userId
                $query = "UPDATE users SET avatar = '$newFilename' WHERE id = $userId";
                // 执行数据库查询
            } else {
                echo "头像上传失败";
            }
        } else {
            echo "请上传符合要求的图片文件";
        }
    }
?>

<?php
    $userId = $_SESSION['userId']; // 假设当前登录用户的ID为userId
    $query = "SELECT avatar FROM users WHERE id = $userId";
    
    // 执行数据库查询 $result = ...
    
    if($result && mysqli_num_rows($result) > 0) {
        $row = mysqli_fetch_assoc($result);
        $avatar = $row['avatar'];
        
        // 头像展示
        echo "<img src='avatars/$avatar' alt='用户头像'>";
    } else {
        // 默认头像展示
        echo "<img src='avatars/default.jpg' alt='默认头像'>";
    }
?>

<?php
    $userId = $_SESSION['userId']; // 假设当前登录用户的ID为userId
    $backgroundColor = $_POST['backgroundColor'];
    $backgroundImage = $_POST['backgroundImage'];
    
    $query = "UPDATE users SET background_color = '$backgroundColor', background_image = '$backgroundImage' WHERE id = $userId";
    // 执行数据库查询
    
    // 重定向到设置页面或其他页面
?>