PHP文件上传至S3：避免本地存储的策略与考量

$_FILES = [
    'myFile' => [
        'name' => 'example.jpg',
        'type' => 'image/jpeg',
        'tmp_name' => '/tmp/phpXYZ123', // 临时文件路径
        'error' => 0,
        'size' => 123456
    ]
];

// 常见用法：传入文件路径
$s3Client->upload($bucket, $key, fopen('/tmp/phpXYZ123', 'r'));

// 或者直接使用文件路径
$s3Client->upload($bucket, $key, '/tmp/phpXYZ123');

<?php
require 'vendor/autoload.php';

use Aws\S3\S3Client;
use Aws\Exception\AwsException;

// 替换为你的AWS凭证和区域
$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',
    ],
]);

$bucketName = 'your-s3-bucket-name';
$objectKey = 'uploads/' . uniqid() . '-' . $_POST['filename']; // 生成唯一的S3对象键

try {
    // 创建一个命令对象，用于PUT操作
    $command = $s3Client->getCommand('PutObject', [
        'Bucket' => $bucketName,
        'Key'    => $objectKey,
        // 'ContentType' => 'image/jpeg', // 可选：指定文件类型，前端上传时需匹配
        // 'ACL' => 'public-read', // 可选：设置文件权限
    ]);

    // 生成预签名URL，有效期为1小时
    $request = $s3Client->createPresignedRequest($command, '+1 hour');
    $presignedUrl = (string) $request->getUri();

    echo json_encode([
        'status' => 'success',
        'presignedUrl' => $presignedUrl,
        'objectKey' => $objectKey // 返回对象键，以便后续在数据库中记录
    ]);

} catch (AwsException $e) {
    // 处理错误
    error_log("Error generating presigned URL: " . $e->getMessage());
    echo json_encode(['status' => 'error', 'message' => $e->getMessage()]);
}
?>

document.getElementById('uploadForm').addEventListener('submit', async function(event) {
    event.preventDefault();

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

    if (!file) {
        alert('请选择一个文件！');
        return;
    }

    try {
        // 1. 请求PHP后端获取预签名URL
        const response = await fetch('/generate-presigned-url.php', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({ filename: file.name })
        });
        const data = await response.json();

        if (data.status === 'error') {
            alert('获取预签名URL失败: ' + data.message);
            return;
        }

        const presignedUrl = data.presignedUrl;
        const objectKey = data.objectKey;

        // 2. 使用预签名URL直接上传文件到S3
        await fetch(presignedUrl, {
            method: 'PUT',
            headers: {
                'Content-Type': file.type // 必须与文件实际类型匹配
            },
            body: file
        });

        alert('文件上传到S3成功！S3路径: ' + objectKey);
        // 3. （可选）通知PHP服务器上传完成
        // await fetch('/file-uploaded-callback.php', {
        //     method: 'POST',
        //     headers: { 'Content-Type': 'application/json' },
        //     body: JSON.stringify({ objectKey: objectKey, originalFilename: file.name })
        // });

    } catch (error) {
        console.error('上传失败:', error);
        alert('文件上传失败: ' + error.message);
    }
});

<?php
// 仅适用于非常小的文件，且需确保服务器有足够内存
if (isset($_FILES['myFile']) && $_FILES['myFile']['error'] === UPLOAD_ERR_OK) {
    $tmpFilePath = $_FILES['myFile']['tmp_name'];
    $fileContent = file_get_contents($tmpFilePath); // 将整个文件读入内存

    // ... S3Client 初始化 ...

    try {
        $s3Client->putObject([
            'Bucket' => $bucketName,
            'Key'    => 'uploads/' . $_FILES['myFile']['name'],
            'Body'   => $fileContent, // 直接将内存中的文件内容作为Body
            'ContentType' => $_FILES['myFile']['type'],
        ]);
        // 删除临时文件，尽管S3 SDK不直接使用它，但PHP已创建
        unlink($tmpFilePath);
        echo "文件上传成功！";
    } catch (AwsException $e) {
        error_log("S3上传失败: " . $e->getMessage());
        echo "S3上传失败。";
    }
}
?>