PHP8在线教程文档

PHP超级全局变量综合示例

<?php
// 1. 输入验证和过滤示例

echo "<h4>1. 输入验证和过滤示例</h4>";

// 获取用户输入并过滤
$username = filter_input(INPUT_GET, 'username', FILTER_SANITIZE_STRING);
$email = filter_input(INPUT_GET, 'email', FILTER_VALIDATE_EMAIL);
$age = filter_input(INPUT_GET, 'age', FILTER_VALIDATE_INT, array('options' => array('min_range' => 18, 'max_range' => 120)));

// 输出过滤后的结果
echo "用户名: " . htmlspecialchars($username) . "<br>";

echo "电子邮件: ";
if ($email !== false) {
    echo $email . " (有效)<br>";
} else {
    echo "无效的电子邮件地址<br>";
}

echo "年龄: ";
if ($age !== false) {
    echo $age . " (有效)<br>";
} else {
    echo "无效的年龄（必须在18-120之间）<br>";
}

// 2. 使用$_SERVER构建URL示例

echo "<h4>2. 使用$_SERVER构建URL示例</h4>";

// 获取当前页面的完整URL
function get_current_url() {
    $protocol = isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] === 'on' ? 'https' : 'http';
    $host = $_SERVER['HTTP_HOST'];
    $uri = $_SERVER['REQUEST_URI'];
    return $protocol . '://' . $host . $uri;
}

echo "当前页面URL: " . get_current_url() . "<br>";

// 3. 简单的表单处理示例

echo "<h4>3. 简单的表单处理示例</h4>";

// 显示表单
if ($_SERVER['REQUEST_METHOD'] === 'GET') {
    echo '<form method="post" action="' . htmlspecialchars($_SERVER['PHP_SELF']) . '">
        姓名: <input type="text" name="name"><br>
        电子邮件: <input type="email" name="email"><br>
        留言: <textarea name="message" rows="4" cols="50"></textarea><br>
        <input type="submit" name="submit" value="提交">
    </form>';
} else if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // 处理表单提交
    $name = htmlspecialchars(trim($_POST['name']));
    $email = htmlspecialchars(trim($_POST['email']));
    $message = htmlspecialchars(trim($_POST['message']));
    
    // 简单验证
    if (empty($name) || empty($email) || empty($message)) {
        echo "所有字段都是必需的！<br>";
    } else {
        // 模拟保存数据
        echo "表单提交成功！<br>";
        echo "姓名: " . $name . "<br>";
        echo "电子邮件: " . $email . "<br>";
        echo "留言: " . $message . "<br>";
    }
}

// 4. 文件上传安全示例

echo "<h4>4. 文件上传安全示例</h4>";

// 显示文件上传表单
if ($_SERVER['REQUEST_METHOD'] === 'GET') {
    echo '<form method="post" enctype="multipart/form-data" action="' . htmlspecialchars($_SERVER['PHP_SELF']) . '">
        选择图片: <input type="file" name="image" accept="image/*"><br>
        <input type="submit" name="upload" value="上传图片">
    </form>';
} else if (isset($_POST['upload']) && isset($_FILES['image'])) {
    // 定义允许的文件类型
    $allowed_types = array('image/jpeg', 'image/png', 'image/gif');
    $max_size = 2 * 1024 * 1024; // 2MB
    
    $file_name = $_FILES['image']['name'];
    $file_tmp = $_FILES['image']['tmp_name'];
    $file_size = $_FILES['image']['size'];
    $file_error = $_FILES['image']['error'];
    $file_type = $_FILES['image']['type'];
    
    // 获取文件扩展名
    $file_ext = strtolower(pathinfo($file_name, PATHINFO_EXTENSION));
    
    // 生成唯一的文件名
    $new_file_name = uniqid('img_', true) . '.' . $file_ext;
    
    // 定义上传目录
    $upload_dir = 'uploads/';
    $upload_path = $upload_dir . $new_file_name;
    
    // 检查是否有错误
    if ($file_error !== UPLOAD_ERR_OK) {
        echo "上传错误！错误代码: " . $file_error . "<br>";
    } else if (!in_array($file_type, $allowed_types)) {
        echo "不允许的文件类型！只允许JPG, PNG和GIF格式。<br>";
    } else if ($file_size > $max_size) {
        echo "文件太大！最大允许2MB。<br>";
    } else {
        // 创建上传目录（如果不存在）
        if (!is_dir($upload_dir)) {
            mkdir($upload_dir, 0777, true);
        }
        
        // 移动文件到上传目录
        if (move_uploaded_file($file_tmp, $upload_path)) {
            echo "文件上传成功！<br>";
            echo "上传的文件: " . $new_file_name . "<br>";
            echo "文件大小: " . ($file_size / 1024) . " KB<br>";
            echo "文件类型: " . $file_type . "<br>";
        } else {
            echo "文件移动失败！<br>";
        }
    }
}

// 5. 简单的用户认证系统示例

echo "<h4>5. 简单的用户认证系统示例</h4>";

session_start();

// 模拟用户数据库
$users = array(
    'admin' => password_hash('admin123', PASSWORD_DEFAULT),
    'user1' => password_hash('user123', PASSWORD_DEFAULT)
);

// 注销功能
if (isset($_GET['logout'])) {
    session_destroy();
    echo "您已成功注销！<br>";
}

// 检查用户是否已登录
if (isset($_SESSION['username'])) {
    echo "欢迎，" . $_SESSION['username'] . "！<br>";
    echo "<a href='?logout'>注销</a>";
} else {
    // 显示登录表单
    if ($_SERVER['REQUEST_METHOD'] === 'GET') {
        echo '<form method="post" action="' . htmlspecialchars($_SERVER['PHP_SELF']) . '">
            用户名: <input type="text" name="username"><br>
            密码: <input type="password" name="password"><br>
            <input type="submit" name="login" value="登录">
        </form>';
    } else if (isset($_POST['login'])) {
        // 处理登录请求
        $username = trim($_POST['username']);
        $password = trim($_POST['password']);
        
        // 验证用户
        if (isset($users[$username]) && password_verify($password, $users[$username])) {
            // 设置会话变量
            $_SESSION['username'] = $username;
            echo "登录成功！欢迎，" . $username . "！<br>";
            echo "<a href='?logout'>注销</a>";
        } else {
            echo "用户名或密码错误！<br>";
        }
    }
}

// 6. 购物车功能示例

echo "<h4>6. 购物车功能示例</h4>";

session_start();

// 初始化购物车
if (!isset($_SESSION['cart'])) {
    $_SESSION['cart'] = array();
}

// 模拟产品数据库
$products = array(
    1 => array('name' => '产品1', 'price' => 100),
    2 => array('name' => '产品2', 'price' => 200),
    3 => array('name' => '产品3', 'price' => 300),
    4 => array('name' => '产品4', 'price' => 400),
    5 => array('name' => '产品5', 'price' => 500)
);

// 添加到购物车
if (isset($_GET['add_to_cart']) && isset($products[$_GET['add_to_cart']])) {
    $product_id = $_GET['add_to_cart'];
    if (isset($_SESSION['cart'][$product_id])) {
        $_SESSION['cart'][$product_id]++;
    } else {
        $_SESSION['cart'][$product_id] = 1;
    }
    echo "产品已添加到购物车！<br>";
}

// 从购物车中删除
if (isset($_GET['remove_from_cart']) && isset($_SESSION['cart'][$_GET['remove_from_cart']])) {
    unset($_SESSION['cart'][$_GET['remove_from_cart']]);
    echo "产品已从购物车中删除！<br>";
}

// 更新购物车数量
if (isset($_POST['update_cart'])) {
    foreach ($_POST['quantity'] as $product_id => $quantity) {
        if (isset($_SESSION['cart'][$product_id])) {
            $quantity = (int)$quantity;
            if ($quantity > 0) {
                $_SESSION['cart'][$product_id] = $quantity;
            } else {
                unset($_SESSION['cart'][$product_id]);
            }
        }
    }
    echo "购物车已更新！<br>";
}

// 清空购物车
if (isset($_GET['clear_cart'])) {
    $_SESSION['cart'] = array();
    echo "购物车已清空！<br>";
}

// 显示产品列表
if ($_SERVER['REQUEST_METHOD'] === 'GET') {
    echo "<h5>产品列表</h5>";
    echo "<table border='1' cellspacing='0' cellpadding='5'>";
    echo "<tr><th>产品名称</th><th>价格</th><th>操作</th></tr>";
    foreach ($products as $id => $product) {
        echo "<tr>";
        echo "<td>" . $product['name'] . "</td>";
        echo "<td>￥" . $product['price'] . "</td>";
        echo "<td><a href='?add_to_cart=" . $id . "'>添加到购物车</a></td>";
        echo "</tr>";
    }
    echo "</table>";
    
    // 显示购物车
    if (!empty($_SESSION['cart'])) {
        $total = 0;
        echo "<h5>您的购物车</h5>";
        echo "<form method='post' action='" . htmlspecialchars($_SERVER['PHP_SELF']) . "'>";
        echo "<table border='1' cellspacing='0' cellpadding='5'>";
        echo "<tr><th>产品名称</th><th>单价</th><th>数量</th><th>小计</th><th>操作</th></tr>";
        foreach ($_SESSION['cart'] as $product_id => $quantity) {
            $product = $products[$product_id];
            $subtotal = $product['price'] * $quantity;
            $total += $subtotal;
            echo "<tr>";
            echo "<td>" . $product['name'] . "</td>";
            echo "<td>￥" . $product['price'] . "</td>";
            echo "<td><input type='number' name='quantity[" . $product_id . "]' value='" . $quantity . "' min='1'></td>";
            echo "<td>￥" . $subtotal . "</td>";
            echo "<td><a href='?remove_from_cart=" . $product_id . "'>删除</a></td>";
            echo "</tr>";
        }
        echo "<tr><td colspan='3' align='right'>总计</td><td colspan='2'>￥" . $total . "</td></tr>";
        echo "</table>";
        echo "<br>";
        echo "<input type='submit' name='update_cart' value='更新购物车'>";
        echo "<a href='?clear_cart'>清空购物车</a>";
        echo "</form>";
    } else {
        echo "您的购物车是空的！<br>";
    }
}

// 7. 语言切换示例

echo "<h4>7. 语言切换示例</h4>";

// 语言选项
$languages = array(
    'en' => 'English',
    'zh' => '中文',
    'es' => 'Español',
    'fr' => 'Français'
);

// 设置默认语言
$default_language = 'en';

// 检查用户选择的语言
if (isset($_GET['lang']) && isset($languages[$_GET['lang']])) {
    $selected_language = $_GET['lang'];
    // 设置Cookie（有效期为30天）
    setcookie('language', $selected_language, time() + (86400 * 30), '/');
} else if (isset($_COOKIE['language']) && isset($languages[$_COOKIE['language']])) {
    // 使用Cookie中保存的语言
    $selected_language = $_COOKIE['language'];
} else {
    // 使用默认语言
    $selected_language = $default_language;
}

// 显示语言选择器
echo "选择语言: ";
foreach ($languages as $code => $name) {
    if ($code === $selected_language) {
        echo $name . ' ';
    } else {
        echo "<a href='?lang=" . $code . "'>" . $name . "</a> <br>";
    }
}

echo "<br>";

// 显示当前语言的文本
$translations = array(
    'welcome' => array(
        'en' => 'Welcome to our website!',
        'zh' => '欢迎访问我们的网站！',
        'es' => '¡Bienvenido a nuestro sitio web!',
        'fr' => 'Bienvenue sur notre site web!'
    ),
    'greeting' => array(
        'en' => 'Hello, visitor!',
        'zh' => '您好，访客！',
        'es' => '¡Hola, visitante!',
        'fr' => 'Bonjour, visiteur!'
    )
);

echo $translations['welcome'][$selected_language] . "<br>";
echo $translations['greeting'][$selected_language] . "<br>";

// 8. 错误日志记录示例

echo "<h4>8. 错误日志记录示例</h4>";

// 自定义错误日志函数
function log_error($message, $level = 'error') {
    // 定义日志文件路径
    $log_file = 'error_log.txt';
    
    // 获取当前时间
    $timestamp = date('Y-m-d H:i:s');
    
    // 获取客户端IP地址
    $ip_address = $_SERVER['REMOTE_ADDR'];
    
    // 构建日志消息
    $log_message = "[$timestamp] [$level] [$ip_address] $message\n";
    
    // 写入日志文件
    error_log($log_message, 3, $log_file);
    
    // 显示日志消息（实际应用中可能不需要显示）
    echo "已记录日志: " . nl2br(htmlspecialchars($log_message)) . "<br>";
}

// 测试日志记录
log_error("这是一个测试错误日志");
log_error("这是一个警告日志", 'warning');
log_error("用户 ".htmlspecialchars($_SERVER['PHP_AUTH_USER'] ?? '匿名')." 访问了受保护页面", 'info');

// 9. 用户跟踪示例

echo "<h4>9. 用户跟踪示例</h4>";

// 检查用户是否有跟踪ID
if (!isset($_COOKIE['visitor_id'])) {
    // 生成唯一的跟踪ID
    $visitor_id = uniqid('visitor_', true);
    // 设置Cookie（有效期为1年）
    setcookie('visitor_id', $visitor_id, time() + (86400 * 365), '/');
} else {
    $visitor_id = $_COOKIE['visitor_id'];
}

echo "您的访问ID: " . $visitor_id . "<br>";

// 记录用户访问信息
function log_visit() {
    global $visitor_id;
    
    // 定义访问日志文件路径
    $visit_log_file = 'visit_log.txt';
    
    // 获取访问信息
    $timestamp = date('Y-m-d H:i:s');
    $ip_address = $_SERVER['REMOTE_ADDR'];
    $user_agent = $_SERVER['HTTP_USER_AGENT'];
    $page_url = get_current_url();
    
    // 构建访问日志消息
    $visit_log_message = "[$timestamp] [$visitor_id] [$ip_address] [$user_agent] $page_url\n";
    
    // 写入访问日志文件
    error_log($visit_log_message, 3, $visit_log_file);
    
    // 显示访问日志消息（实际应用中可能不需要显示）
    echo "已记录访问: " . nl2br(htmlspecialchars($visit_log_message)) . "<br>";
}

// 测试访问记录
log_visit();

// 10. 简单的内容分页示例

echo "<h4>10. 简单的内容分页示例</h4>";

// 模拟内容数据
$items_per_page = 10;
$total_items = 57;
$total_pages = ceil($total_items / $items_per_page);

// 获取当前页码
$current_page = isset($_GET['page']) ? (int)$_GET['page'] : 1;
$current_page = max(1, min($current_page, $total_pages));

// 计算偏移量
$offset = ($current_page - 1) * $items_per_page;

// 模拟获取数据
$start_item = $offset + 1;
$end_item = min($offset + $items_per_page, $total_items);

echo "显示第 $start_item 到 $end_item 条，共 $total_items 条记录<br><br>";

// 显示分页链接
function display_pagination($total_pages, $current_page, $url) {
    echo "<div class='pagination'>";
    
    // 上一页
    if ($current_page > 1) {
        echo "<a href='?page=" . ($current_page - 1) . "'>上一页</a> ";
    }
    
    // 显示页码
    for ($i = 1; $i <= $total_pages; $i++) {
        if ($i == $current_page) {
            echo "<span class='current-page'>$i</span> ";
        } else {
            echo "<a href='?page=$i'>$i</a> ";
        }
    }
    
    // 下一页
    if ($current_page < $total_pages) {
        echo "<a href='?page=" . ($current_page + 1) . "'>下一页</a>";
    }
    
    echo "</div>";
}

display_pagination($total_pages, $current_page, $_SERVER['PHP_SELF']);

// 显示当前页的内容（模拟）
echo "<h5>第 $current_page 页的内容</h5>";
echo "<ul>";
for ($i = $start_item; $i <= $end_item; $i++) {
    echo "<li>内容项 $i</li>";
}
echo "</ul>";
?>