PHP实现HTML表单文件直接上传至S3：避免本地存储的策略与实践

<?php
require 'vendor/autoload.php'; // 假设你使用Composer管理依赖

use Aws\S3\S3Client;
use Aws\CommandPool;
use Aws\S3\PostObjectV4;

// 配置AWS S3客户端
$s3Client = new S3Client([
    'version'     => 'latest',
    'region'      => 'your-aws-region', // 例如 'us-east-1'
    'credentials' => [
        'key'    => 'your-aws-access-key-id',
        'secret' => 'your-aws-secret-access-key',
    ],
]);

// 假设前端通过AJAX请求发送了文件名和文件类型
if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['fileName'], $_POST['fileType'])) {
    $fileName = $_POST['fileName'];
    $fileType = $_POST['fileType'];
    $bucketName = 'your-s3-bucket-name';
    $key = 'uploads/' . uniqid() . '-' . basename($fileName); // S3中的文件路径

    try {
        // 创建一个PUT命令
        $command = $s3Client->getCommand('PutObject', [
            'Bucket'      => $bucketName,
            'Key'         => $key,
            'ContentType' => $fileType,
            // 'ACL'         => 'public-read', // 如果需要文件公开访问
        ]);

        // 生成预签名URL，有效期为10分钟
        $presignedRequest = $s3Client->createPresignedRequest($command, '+10 minutes');
        $presignedUrl = (string) $presignedRequest->getUri();

        header('Content-Type: application/json');
        echo json_encode([
            'status' => 'success',
            'uploadUrl' => $presignedUrl,
            's3Key' => $key,
            'message' => 'Presigned URL generated successfully.'
        ]);
    } catch (Exception $e) {
        header('Content-Type: application/json', true, 500);
        echo json_encode([
            'status' => 'error',
            'message' => 'Failed to generate presigned URL: ' . $e->getMessage()
        ]);
    }
} else {
    header('Content-Type: application/json', true, 400);
    echo json_encode([
        'status' => 'error',
        'message' => 'Invalid request.'
    ]);
}
?>

// 假设你有一个文件输入框和一个提交按钮
document.getElementById('uploadForm').addEventListener('submit', async function(event) {
    event.preventDefault();

    const fileInput = document.getElementById('fileInput');
    const file = fileInput.files[0];

    if (!file) {
        alert('Please select a file.');
        return;
    }

    try {
        // 1. 请求PHP后端生成预签名URL
        const response = await fetch('/generate-presigned-url.php', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/x-www-form-urlencoded',
            },
            body: `fileName=${encodeURIComponent(file.name)}&fileType=${encodeURIComponent(file.type)}`
        });

        if (!response.ok) {
            throw new Error(`HTTP error! status: ${response.status}`);
        }

        const data = await response.json();
        if (data.status === 'error') {
            throw new Error(data.message);
        }

        const uploadUrl = data.uploadUrl;
        const s3Key = data.s3Key;

        // 2. 使用生成的URL直接上传文件到S3
        const uploadResponse = await fetch(uploadUrl, {
            method: 'PUT',
            headers: {
                'Content-Type': file.type, // 必须设置正确的Content-Type
            },
            body: file // 直接将File对象作为body
        });

        if (!uploadResponse.ok) {
            throw new Error(`S3 upload failed! status: ${uploadResponse.status}`);
        }

        alert('File uploaded to S3 successfully! S3 Key: ' + s3Key);
        // 可以在这里向PHP后端发送一个通知，告知文件已成功上传
        // fetch('/file-upload-complete.php', { method: 'POST', body: JSON.stringify({ s3Key: s3Key }) });

    } catch (error) {
        console.error('Upload error:', error);
        alert('File upload failed: ' + error.message);
    }
});