PHP文件上传至S3：策略、考量与避免本地存储的挑战

<?php

require vendor/autoload.php;

use Aws\S3\S3Client;

use Aws\Exception\AwsException;

// 1. S3 Client配置

$s3Client = new S3Client([

    version => latest,

    region  => your-region, // 例如 us-east-1

    credentials => [

        key    => YOUR_AWS_ACCESS_KEY_ID,

        secret => YOUR_AWS_SECRET_ACCESS_KEY,

    ],

]);

$bucketName = your-s3-bucket-name;

// 2. 处理文件上传表单提交

if ($_SERVER[REQUEST_METHOD] === POST && isset($_FILES[fileToUpload])) {

    $file = $_FILES[fileToUpload];

    // 检查文件上传错误

    if ($file[error] !== UPLOAD_ERR_OK) {

        echo "文件上传错误: " . $file[error];

        // 根据错误码进行更详细的错误处理

        exit;

    }

    $fileName = basename($file[name]);

    $tempFilePath = $file[tmp_name]; // 这是PHP自动创建的临时文件路径

    try {

        // 3. 将临时文件直接上传到S3

        $result = $s3Client->putObject([

            Bucket     => $bucketName,

            Key        => uploads/ . $fileName, // S3中的对象键

            SourceFile => $tempFilePath,           // 直接从临时文件上传

            ContentType => mime_content_type($tempFilePath), // 可选：设置内容类型

            ACL        => private,              // 或 public-read 根据需要设置

            // Metadata => [foo => bar], // 可选：添加元数据

        ]);

        echo "文件上传成功到S3: " . $result[ObjectURL] . "\n";

        // PHP脚本执行结束时通常会自动清理临时文件，

        // 但如果需要立即清理或在特定逻辑中处理，可以使用 unlink($tempFilePath);

    } catch (AwsException $e) {

        echo "上传文件到S3时发生错误: " . $e->getMessage() . "\n";

    }

}

?>

<!-- 对应的HTML表单 -->

<form action="" method="post" enctype="multipart/form-data">

    选择文件上传:

    <input type="file" name="fileToUpload" id="fileToUpload">

    <input type="submit" value="上传文件" name="submit">

</form>

<?php

// PHP后端生成预签名URL的简化示例

require vendor/autoload.php;

use Aws\S3\S3Client;

use Aws\S3\PostObjectV4; // 如果使用POST策略

// S3 Client配置 (同上)

$s3Client = new S3Client([/* ... */]);

$bucketName = your-s3-bucket-name;

// 假设前端请求一个上传凭证

if (isset($_GET[action]) && $_GET[action] === getUploadPresignedUrl) {

    $objectKey = uploads/ . uniqid() . - . $_GET[fileName]; // 生成一个唯一的文件名

    $command = $s3Client->getCommand(PutObject, [

        Bucket => $bucketName,

        Key    => $objectKey,

        ACL    => private, // 或 public-read

        ContentType => $_GET[fileType], // 从前端获取文件类型

    ]);

    $request = $s3Client->createPresignedRequest($command, +20 minutes); // 20分钟内有效

    header(Content-Type: application/json);

    echo json_encode([

        uploadUrl => (string) $request->getUri(),

        objectKey => $objectKey

    ]);

    exit;

}

?>

<!-- 对应的HTML和JavaScript概念 -->

<input type="file" id="fileInput">

<button onclick="uploadFile()">上传</button>

<script>

async function uploadFile() {

    const fileInput = document.getElementById(fileInput);

    const file = fileInput.files[0];

    if (!file) {

        alert(请选择一个文件);

        return;

    }

    // 1. 从PHP后端获取预签名URL

    const response = await fetch(`/your_php_endpoint.php?action=getUploadPresignedUrl&fileName=${file.name}&fileType=${file.type}`);

    const data = await response.json();

    const uploadUrl = data.uploadUrl;

    const objectKey = data.objectKey;

    // 2. 使用Fetch API直接上传到S3

    try {

        const s3Response = await fetch(uploadUrl, {

            method: PUT,

            headers: {

                Content-Type: file.type,

            },

            body: file,

        });

        if (s3Response.ok) {

            console.log(文件成功上传到S3:, objectKey);

            alert(文件上传成功！);

            // 可选：通知PHP后端上传完成，进行数据库记录等

        } else {

            console.error(S3上传失败:, s3Response.statusText);

            alert(文件上传失败！);

        }

    } catch (error) {

        console.error(上传过程中发生错误:, error);

        alert(上传过程中发生错误！);

    }

}

</script>