PHP 接收 HTTP POST 提交的 XML 資料並解析實作

當第三方系統或前端透過 HTTP POST 直接送出 XML 內容（Content-Type: text/xml 或 application/xml）時，PHP $_POST 無法自動解析，需從原始輸入流讀取並解析。

核心步驟

1. 讀取原始 POST 資料：file_get_contents('php://input')（推薦）或 $GLOBALS['HTTP_RAW_POST_DATA']（PHP 5.6+ 棄用、7.0+ 移除）
2. 解析 XML：simplexml_load_string()（簡單結構）或 DOMDocument（複雜、需命名空間、XPath）
3. 錯誤處理：關閉 libxml 錯誤報告，自行捕獲

完整實作範例

<?php
declare(strict_types=1);

// 僅允許 POST
if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(405);
    exit('Method Not Allowed');
}

// 1. 讀取原始 XML
$rawXml = file_get_contents('php://input');
if (empty($rawXml)) {
    http_response_code(400);
    exit('Empty XML body');
}

// 2. 解析（關閉 libxml 內部錯誤，改由程式碼處理）
libxml_use_internal_errors(true);
$xml = simplexml_load_string($rawXml);
$errors = libxml_get_errors();
libxml_clear_errors();

if ($xml === false) {
    $msg = 'XML 解析失敗: ' . implode('; ', array_map(fn($e) => $e->message, $errors));
    error_log($msg);
    http_response_code(400);
    exit($msg);
}

// 3. 取得資料（範例結構對應原文）
$namespace = ''; // 若有命名空間需註冊：$xml->registerXPathNamespace('ns', 'uri');
$iata = (string)($xml->Agency->Iata ?? '');
$agent = (string)($xml->Agency->Agent ?? '');
$password = (string)($xml->Agency->Password ?? '');
$brand = (string)($xml->Agency->Brand ?? '');

$adults = [];
foreach ($xml->Passengers->Adult ?? [] as $adult) {
    $adults[] = [
        'id' => (string)($adult['ID'] ?? ''),
        'age' => (string)($adult['AGE'] ?? ''),
    ];
}

$destCode = (string)($xml->HotelAvailReq1->DestCode ?? '');
$hotelCode = (string)($xml->HotelAvailReq1->HotelCode ?? '');
$checkIn = (string)($xml->HotelAvailReq1->CheckInDate ?? '');
$checkOut = (string)($xml->HotelAvailReq1->CheckOutDate ?? '');
$useField = (string)($xml->HotelAvailReq1->UseField ?? '');

// 4. 業務邏輯處理...
// $result = processBooking($iata, $agent, $adults, $destCode, $hotelCode, $checkIn, $checkOut);

// 5. 回應 XML
header('Content-Type: text/xml; charset=utf-8');
echo <<

$dom = new DOMDocument();
$dom->loadXML($rawXml, LIBXML_NOERROR | LIBXML_NOWARNING);
$xpath = new DOMXPath($dom);

// 註冊命名空間（若 XML 含 xmlns）
// $xpath->registerNamespace('ns', 'https://example.com/ns');

$iata = $xpath->evaluate('string(//Agency/Iata)');
$adultNodes = $xpath->query('//Passengers/Adult');
foreach ($adultNodes as $node) {
    $id = $node->getAttribute('ID');
    $age = $node->getAttribute('AGE');
    // ...
}

<?php
$xmlData = '<AATAvailReq1><Agency><Iata>1234567890</Iata>...</AATAvailReq1>';

$ch = curl_init('https://your-api.example.com/endpoint');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_POSTFIELDS => $xmlData,
    CURLOPT_HTTPHEADER => [
        'Content-Type: text/xml; charset=utf-8',
        'Content-Length: ' . strlen($xmlData),
    ],
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_SSL_VERIFYPEER => true, // 生產環境必須驗證
    CURLOPT_TIMEOUT => 30,
]);
$response = curl_exec($ch);
$httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

echo "HTTP $httpCode\n$response";