如何将 .zip 文件提取到 lambda 函数中的目录

Question

我遇到的问题是，当我针对 .zip 文件测试函数时，当函数到达 fs.createReadStream&Zip 时，函数没有运行或返回错误，我想了解什么我做错了，正确的解决方案看起来如何。

const AWS = require('aws-sdk');
const fs = require('fs');
const mkdirp = require('mkdirp');
const unzipper = require('unzipper');

exports.handler = async (event, context) => {

    // Variables for bucket init
    let sourceBucket = 'am-doc-mgmt-s3-dev-landing';
    let storageBucket = 'am-doc-mgmt-s3-dev';

    // Variables for folder init and Buffer config
    const localZippedFolder = '/tmp/ZippedStudentData/';
    const localUnzippedFolder = '/tmp/UnzippedStudentData/';

    const ZipBuffer = Buffer.from(localZippedFolder, 'base64');
    const UnzippedBuffer = Buffer.from(localUnzippedFolder, 'base64');

    // Inits AWS s3 Bucket and DynamoDB
    let s3 = new AWS.S3();
    let docClient = new AWS.DynamoDB.DocumentClient({ region: 'us-east-1' });

    // Gets the file bucket and file name of the s3 object from context
    let fileBucket = event.Records[0].s3.bucket.name;
    let fileName = event.Records[0].s3.object.key;
    let params = {
        Bucket: fileBucket,
        Key: fileName
    };

    // Creates temporary variables
    let tempFile = localZippedFolder + fileBucket;
    let tempUnzippedFile = localUnzippedFolder + fileBucket;

    // Make Directories for Zipped and Unzipped files
    try {
        const zipDirFolder = await mkdirp(localZippedFolder, { recursive: true })
        const unZipDirFolder = await mkdirp(localUnzippedFolder, { recursive: true });
        console.log('SUCCESS: unzipped directory created!');
        console.log('SUCCESS: zipped directory create!')

    // Download files from s3 Bucket
        let newFolder = await s3.getObject(params).promise()
        .then(data => {
            console.log(data);
            return data;
        });

    // Extract files from zipped folder and store them in a local directory
       fs.createReadStream(params.Key)
        .pipe(unzipper.Extract({path: unZipDirFolder}))
        .on('finish', () => {
             fs.readdir(unZipDirFolder);
        }).on('error', (err) => {
             // error handling here
             console.log(err);
    });

    }   
     catch (error) {
        console.log(error);
    }
};

错误：没有从 fs.createReadStream 函数返回任何内容。就好像它只是跳过了该功能。

Answer 1

说实话，很难弄清楚您真正想要解决的问题是什么，因为您对此并不是很具体。如果您希望包含 async 的函数在解压缩完成之前不解析它的承诺，您可以将流包装在这样的承诺中：

const AWS = require('aws-sdk');
const fs = require('fs');
const mkdirp = require('mkdirp');
const unzipper = require('unzipper');

exports.handler = async (event, context) => {

    // Variables for bucket init
    let sourceBucket = 'am-doc-mgmt-s3-dev-landing';
    let storageBucket = 'am-doc-mgmt-s3-dev';

    // Variables for folder init and Buffer config
    const localZippedFolder = '/tmp/ZippedStudentData/';
    const localUnzippedFolder = '/tmp/UnzippedStudentData/';

    const ZipBuffer = Buffer.from(localZippedFolder, 'base64');
    const UnzippedBuffer = Buffer.from(localUnzippedFolder, 'base64');

    // Inits AWS s3 Bucket and DynamoDB
    let s3 = new AWS.S3();
    let docClient = new AWS.DynamoDB.DocumentClient({ region: 'us-east-1' });

    // Gets the file bucket and file name of the s3 object from context
    let fileBucket = event.Records[0].s3.bucket.name;
    let fileName = event.Records[0].s3.object.key;
    let params = {
        Bucket: fileBucket,
        Key: fileName
    };

    // Creates temporary variables
    let tempFile = localZippedFolder + fileBucket;
    let tempUnzippedFile = localUnzippedFolder + fileBucket;

    // Make Directories for Zipped and Unzipped files
    try {
        const zipDirFolder = await mkdirp(localZippedFolder, { recursive: true })
        const unZipDirFolder = await mkdirp(localUnzippedFolder, { recursive: true });
        console.log('SUCCESS: unzipped directory created!');
        console.log('SUCCESS: zipped directory create!')

        // Download files from s3 Bucket
        let newFolder = await s3.getObject(params).promise();

        await new Promise((resolve, reject) => {
            // Extract files from zipped folder and store them in a local directory
           fs.createReadStream(params.Key)
                .pipe(unzipper.Extract({path: unZipDirFolder}))
                .on('finish', resolve);
                .on('error', reject);
        });

    } catch (error) {
        console.log(error);
        // rethrow error so caller sees the error
        throw error;
    }
};

而且，使用此导出函数的调用者必须在返回的承诺上使用 .then() 或 await 才能知道何时完成。并且，在await 周围使用.catch() 或try/catch 来捕获错误。