使用PHP和XML实现表单数据处理和验证

<form method="POST" action="process.php">
    <label for="name">姓名：</label>
    <input type="text" name="name" id="name" required>
    <br>
    <label for="email">邮箱：</label>
    <input type="email" name="email" id="email" required>
    <br>
    <label for="phone">电话：</label>
    <input type="text" name="phone" id="phone" required>
    <br>
    <input type="submit" value="提交">
</form>

<?xml version="1.0" encoding="UTF-8"?>
<fields>
    <field name="name">
        <required>true</required>
        <min_length>2</min_length>
        <max_length>50</max_length>
    </field>
    <field name="email">
        <required>true</required>
        <pattern>^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+.[a-zA-Z]{2,4}$</pattern>
    </field>
    <field name="phone">
        <required>true</required>
        <pattern>^d{11}$</pattern>
    </field>
</fields>

<?php
// 读取XML配置文件
$xml = simplexml_load_file("config.xml");

// 处理表单数据
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $errors = [];

    foreach ($_POST as $key => $value) {
        // 根据字段名获取对应的验证规则
        $field = $xml->xpath("//field[@name='$key']")[0];
        
        // 验证是否必填
        if ((string)$field->required == "true" && empty($value)) {
            $errors[$key] = "必填字段";
        }
        
        // 验证长度
        $length = strlen($value);
        if ((string)$field->min_length && $length < (int)$field->min_length) {
            $errors[$key] = "长度太短";
        }
        if ((string)$field->max_length && $length > (int)$field->max_length) {
            $errors[$key] = "长度太长";
        }
        
        // 验证正则表达式
        if ((string)$field->pattern && !preg_match("/" . (string)$field->pattern . "/i", $value)) {
            $errors[$key] = "格式不正确";
        }
    }

    // 输出错误信息或成功提示
    if (count($errors) > 0) {
        echo "表单验证失败：";
        foreach ($errors as $key => $error) {
            echo $key . " " . $error . "<br>";
        }
    } else {
        echo "表单验证成功！";
    }
}
?>