PHP表单提交与服务器端函数调用机制解析

<form method="post">
    <!-- 其他表单元素 -->
    <input type="submit" name="submit" value="提交" onclick="submitData()" />
</form>

<?php
function submitData() {
    // 数据库更新逻辑
    echo "数据已提交！";
}
// ...
?>

<form method="post" action="">
    <h2>元数据</h2>
    <h3>描述</h3>
    <!-- 假设这里有描述的textarea -->
    <textarea id="services-description" name="services-description" rows="5"></textarea>

    <h3>标题</h3>
    <?php
    // getTitle() 函数用于从数据库获取数据并填充表单
    function getTitle() {
        // 实际应用中请替换为您的数据库连接信息
        $connection = new PDO('mysql:host=localhost;dbname=your_db;charset=utf8', 'user', 'password');
        $query      = $connection->query("SELECT `value` FROM `services` WHERE `type` = 'title';");
        $data       = $query->fetchAll(PDO::FETCH_COLUMN);
        echo '<textarea id="services-title" name="services-title" rows="1">' . htmlentities($data[0] ?? '') . '</textarea>';
    }
    getTitle();
    ?>
    <!-- 假设这里有其他表单元素，如meta_keywords和content -->
    <h3>关键词</h3>
    <textarea id="services-meta_keywords" name="services-meta_keywords" rows="1"></textarea>
    <h3>内容</h3>
    <textarea id="services-content" name="services-content" rows="10"></textarea>

    <div class="flex-row-right">
        <input type="submit" name="submit" value="提交" />
    </div>
</form>

<?php

// 数据库连接配置 (实际应用中应更安全地管理)
define('DB_HOST', 'localhost');
define('DB_NAME', 'your_db');
define('DB_USER', 'user');
define('DB_PASS', 'password');
define('DB_CHARSET', 'utf8');

/**
 * 获取标题数据并输出textarea
 */
function getTitle() {
    try {
        $connection = new PDO("mysql:host=" . DB_HOST . ";dbname=" . DB_NAME . ";charset=" . DB_CHARSET, DB_USER, DB_PASS);
        $connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); // 设置错误模式
        $query      = $connection->prepare("SELECT `value` FROM `services` WHERE `type` = 'title';");
        $query->execute();
        $data       = $query->fetchAll(PDO::FETCH_COLUMN);
        echo '<textarea id="services-title" name="services-title" rows="1">' . htmlentities($data[0] ?? '') . '</textarea>';
    } catch (PDOException $e) {
        error_log("数据库错误 (getTitle): " . $e->getMessage());
        echo '<textarea id="services-title" name="services-title" rows="1">加载失败</textarea>';
    }
}

/**
 * 提交数据到数据库
 */
function submitData() {
    // 检查是否是通过POST请求提交
    if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['submit'])) {
        try {
            $connection = new PDO("mysql:host=" . DB_HOST . ";dbname=" . DB_NAME . ";charset=" . DB_CHARSET, DB_USER, DB_PASS);
            $connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); // 设置错误模式

            // 使用预处理语句防止SQL注入是最佳实践
            $stmt = $connection->prepare("UPDATE `services` SET `value` = :value WHERE `type` = :type;");

            // 更新描述
            if (isset($_POST['services-description'])) {
                $stmt->execute([':value' => $_POST['services-description'], ':type' => 'description']);
            }

            // 更新关键词
            if (isset($_POST['services-meta_keywords'])) {
                $stmt->execute([':value' => $_POST['services-meta_keywords'], ':type' => 'meta_keywords']);
            }

            // 更新标题
            if (isset($_POST['services-title'])) {
                $stmt->execute([':value' => $_POST['services-title'], ':type' => 'title']);
            }

            // 更新内容 (注意对HTML内容的特殊处理，这里使用htmlspecialchars)
            if (isset($_POST['services-content'])) {
                $stmt->execute([':value' => htmlspecialchars($_POST['services-content']), ':type' => 'content']);
            }

            // 提交成功后通常会重定向或显示成功消息
            // header("Location: success.php"); // 示例重定向
            // exit();
            echo "<p style='color:green;'>数据更新成功！</p>";

        } catch (PDOException $e) {
            error_log("数据库错误 (submitData): " . $e->getMessage());
            echo "<p style='color:red;'>数据更新失败：" . $e->getMessage() . "</p>";
        }
    }
}

// 在脚本开始时检查并调用submitData函数
// 确保在任何HTML输出之前执行此逻辑，以便可以进行HTTP头重定向等操作
if (!empty($_POST['submit'])) {
    submitData();
}

?>

<!-- 以下是您的HTML表单部分 -->
<form method="post" action="">
    <h2>元数据</h2>
    <h3>描述</h3>
    <textarea id="services-description" name="services-description" rows="5"><?php echo isset($_POST['services-description']) ? htmlentities($_POST['services-description']) : ''; ?></textarea>

    <h3>标题</h3>
    <?php getTitle(); ?>

    <h3>关键词</h3>
    <textarea id="services-meta_keywords" name="services-meta_keywords" rows="1"><?php echo isset($_POST['services-meta_keywords']) ? htmlentities($_POST['services-meta_keywords']) : ''; ?></textarea>

    <h3>内容</h3>
    <textarea id="services-content" name="services-content" rows="10"><?php echo isset($_POST['services-content']) ? htmlentities($_POST['services-content']) : ''; ?></textarea>

    <div class="flex-row-right">
        <input type="submit" name="submit" value="提交" />
    </div>
</form>