如何將 Zip 文件從 s3 存儲桶下載到 node.js lambda 函數中的本地目錄

Question

我正在嘗試從 s3 獲取一個 zip 文件並將其存儲在本地目錄中，然后讀取該目錄以確保 zip.file 存在。 有沒有可靠的方法來做到這一點。 當我閱讀以查看文件是否位於 tmp 目錄中時，它不存在。

// MAKE DIRECTORIES FOR ZIPPED AND UNZIPPED FOLDER
const zipDirFolder = await mkdirp(localZippedFolder, { recursive: true });
const unZipDirFolder = await mkdirp(localUnzippedFolder, { recursive: true });

// VERIFY THAT DIRECTORIES ARE CREATED
const zipFolderChecker = fs.statSync(zipDirFolder);
const unZipFolderChecker = fs.statSync(unZipDirFolder);
console.log('SUCCESS: 2 DIRECTORIES CREATED');

// CREATE STREAMS FOR S3 BUCKET OBJECTS
const tempFileName = path.join(zipDirFolder, 'downloaded.zip');
const tempFileDownload = fs.createWriteStream(tempFileName);

// DOWNLOAD ZIP FILE FROM S3 BUCKET TO TEMP FOLDER
const getS3Object = await s3.getObject(params).createReadStream().pipe(tempFileDownload);
console.log('SUCCESS: ZIP FILE DOWNLOADED');

// LIST FILES IN ZIP FOLDER DIRECTORY
await new Promise((resolve, reject) => {
    fs.readdir(zipDirFolder, (error, files) => {
        error ? reject(error) : resolve(files);
        console.log(files)

任何有關如何修復的示例將不勝感激。

Answer 1

基於 AWS 文檔： https : //docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/requests-using-stream-objects.html 。

您的代碼幾乎是正確的，等待下載過程結束的問題。 您能否在代碼中添加調試信息：

const s3Stream = s3.getObject(params).createReadStream();
    s3Stream.on('error', function(err) {
        // NoSuchKey: The specified key does not exist
        console.error(err);
    });
    // there is the main debugging point
    s3Stream.pipe(tempFileDownload).on('error', function(err) {
        // capture any errors that occur when writing data to the file
        console.error('File Stream:', err);
    }).on('close', function() {
        console.log('Done.');
    });

此外，您的流不是在await語句之后關閉，而是on('close', () => {})事件之后on('close', () => {}) 。 您需要將其轉換為承諾：

async getObjectToFile(bucket, key):Promise<void> {     
        return new Promise<void>((res, rej) => {
            // *
            // *
           //your code
s3Stream.pipe(tempFileDownload).on('error', function(err) {
            // capture any errors that occur when writing data to the file
            console.error('File Stream:', err);
            rej(err) ;
        }).on('close', function() {
            console.log('Done.');
            res()
        });

        });
    };